I was given two popular antennas to use for a decent amount of time. I figured to try them both out and share my feelings about each one. I was given the Arrow Satellite II from Arrow antennas and a dual band Log Periodic from Elk Antennas. We’ll look at each antenna individually and then compare them to each other.
Arrow Satellite II
Whenever someone mentions working amateur radio satellites (reapeaters in the sky), the Arrow Satellite II is almost always mentioned. It’s been mentioned so many times that I wanted one. However like most hams, I’m cheap! If I feel that I can make the exact same antenna, I will try my best to do so. I tried looking for the plans for that antenna but couldn’t find them. I was bummed out until someone I knew (N1KXR) purchased a used one from another ham. This was the perfect time to take the antenna and dissect it.
The first thing I did when I got the antenna was to assemble it and PLAY! The actual assembly of the antenna was OK. The reason it’s called an ARROW antenna is because the elements are made from aluminum arrow shafts that are used in archery. The great thing about using arrows is that they are light and built to some strict specs.
I like that it’s light weight and that I can setup the antenna to either VHF or UHF or Both. The duplexer inside the handle is a big plus. I don’t have a spectrum/network analyzer or lab equipment to give you the in-depth specs of the antenna (I just wish I knew) but it shows good SWR on my bridge (meter) and it performs. The only thing I would do if this was mine is to use different color electrical tape (or paint markers) to identify the correct pairs of elements. I lined them up by height. I would also drill a hole in the handle (away from the duplexer) so I could mount the antenna to a tripod better. As I found with the PVC Tape measure yagi, It gets heavy after holding it for awhile.
Let’s Reverse It!
I wanted to make this antenna almost exactly the same way it was purchased. From using arrows shafts all the way down to the micro-duplexer that is in the handle. I didn’t want to drift far away from the original design so out came the 5ft vernier calipers and went to town remaking the entire antenna in CAD.
After putting all the dimensions back into CAD this is what I got. I would like to say it’s within .005″ and the antenna is possible to reproduce if you have access to a drill press, arbor press (can’t tell if the BNCs are pressed) and lathe (Or a good fixture for the drill press) as most of the work would be focused on the driven element/gamma match.
Is it worth making your own?
Even though I have access to some of the material, I wanted to look at as if I had nothing and had to go out and buy all the material. So I started calling around for quotes on material. The more and more I got into it, the price kept climbing and climbing.
Let’s start off with the Arrows. I wanted to use the same aluminum arrows just like the ones that are used on this antenna. I went looking for the Arrows they used based on the dimensions I got from reverse engineering. While trying to find these arrows I learned a lot about all the different types of arrows used in archery. When it comes to aluminum arrows, they use a 4 digit number system. The first two digits are the diameter of the shaft in 1/64″ increments and the last two digits are the wall thickness in 1/1000″. I found out that they are using 1716 arrow and the only ones I can find are by Easton (Easton Blues/Jazz) and they are not cheap. Just the shafts would end up being $60-$70. That doesn’t include the 8-32 Inserts.
The tubing, square stock and bar stock for the boom and gamma match would add up to approx $30.
BNC connectors, Coax, plastic tubing, wire, screws and threaded rod would add up to approx $20.
So far we’re looking at least $100-$120 for the material and that doesn’t even include the micro duplexer. You can purchase the duplexer ready to go from Arrow Antennas for around $60 or you can make it yourself using the plans found on KI0AG’s Site that appears Arrow Antennas used as well. If you don’t have the means or equipment to make/etch your own boards then it will still cost a decent amount of money.
For me, It’s not worth building.
The price of material would meet or exceed the cost of the antenna if you were to buy it from Arrow. This doesn’t include the splitboom, duplexer and labor involved. As much pride as I take in building my own, it’s not worth it. I can buy the antenna already made for less then it would take to manufacture. I tried things like using 1/4″ solid aluminum rod to reduce the materials costs but now you are spending more time in labor in drilling and tapping for a 8-32 screw. A lathe would really help in this situation.
How does it perform?
I can’t get too technical because I don’t have any of the testing gear or the know how to give you exact figures. The following evaluation is just from my personal observations.
The way I received the antenna was in a tube with what appears to be the original plastic bag that separates the UHF and VHF Elements. Since this antenna is used, I am not sure how it comes from the factory. Assembling the Antenna is quite a challenge. The elements are NOT labeled! What I had to do was line up the elements by height and pair them together for both the VHF and UHF side of the beam. For me, most of the time assembling this antenna is spent finding out which element is which. This would be my only complaint about the antenna. However it can be fixed by doing a couple things. Buying multicolored electrical tape and put some tape on the elements and boom. You can also purchase or make your “Antenna” bag with pockets for each pair of elements.
Assembly is pretty much straight forward once you know what goes where, Just screw them together through the boom, hook up the BNC connector and you’re ready to go. I’d suggest the first time you put it together to check SWR and adjust the gamma match for optimal SWR.
I spent some time tracking Sats, hitting repeaters that I can’t normally hit with a rubber duck and some back yard RDF. The antenna performs, I was able to pickup some satellites like the NOAA and some Ham Sats and it performs just like you would expect. There is nothing much more I can say performance wise other than it works.
- Uses aluminum
- Tuneable (Gamma Match)
- Built in duplexor
- Use either 144 or 440 or both.
- Breaks down into a small area
- Elements not marked
- Arrows can break
- Built in duplexor
- Very bulky when assembled
- Hard to transport
If you noticed I put duplexor in both the pros and cons. The reason is because it’s great that you just one connection to the radio but you will have loss at the duplexor. I would assume the loss isn’t much at all so I wouldn’t be to concerned.
When you assemble both the VHF and UHF side of the beam, it turns into quite a bulky object and would be harder to transport inside your car. Not saying it’s impossible but you would most likely have to break down one band of the antenna.
Overall a great antenna and would recommend it to anyone that is serious about portable sat work, RDF and low power operations (<10W)
Elk Log Periodic
Whenever the Arrow antenna is mentioned, the Log Periodic by Elk Antennas is also mentioned and vice verse. The antenna is known as a log periodic which is a little bit similar to a Yagi. Instead of one boom, It uses two booms which the elements that are attached to each boom are 180 degrees from the elements on the other boom. In a simple way I can put it is that it’s a bunch of dipoles of different lengths. When the signal enters the antenna, it will find the best pair of “Dipoles” for that frequency and the other pairs help direct the signal.
Lets reverse it!
Well I didn’t. I didn’t think it was worth it.
The antenna is made with some quality parts. The Booms are thick walled aluminum tubing. They are spaced part using plastic spacers and plastic bolts and it has tapped holes along the boom with #10 screws to hold the elements. The boom is mounted/supported by two different grades of PVC tubing. The PVC used for mounting is schedual 40 and the other appears to be electrical conduit. The elements are also aluminum tubing that appears to have been either wet or powder coated with vinyl caps to protect the ends. They also have pressed in threads (10-32). They are high end tent poles. Included is a Handle made from PVC tubing that has a foam grip fitted to one side. This handle allows for portable ops.
Is it worth making your own?
I priced everything out as if you didn’t have any of this material laying around the house and you started from scratch.
- 4Ft Aluminum tubing for the boom – $25
- 12ft Aluminum tubing for the elements – $35
- PVC for mounting – $10
- Vinyl caps – $5
- Stainless Screws/Nuts (Nylock) – $15
- Plastic Screws/spacers – $10
- SO-239 Chassis mount – $5
Total Materials cost – Approx $105
Just based on materials alone, It’s cheaper than if you were to purchase one.
For Me, It’s not worth building
Even though the materials are cheaper than what it’s being sold for, there is quite a bit of work that has to go into this antenna. One of the booms will have to be machined for a notch to allow the SO-239 connector to sit flush. There is also a LOT of drilling and tapping going on. That means you need a drillpress that is almost perfectly 90 degrees and fixtures/jigs available to drill nicely through round stock. If you don’t have the time or you highly value your time, I can see 4 or so hours in manufacturing and assembly. If you wanted to go all out and powder/wet paint the elements, then you are add more time and costs.
How does it perform?
Once again, I don’t have the equipment to give you a proper assessment of the antenna. The following evaluation is just from my personal observations.
I got the antenna mostly un-assembled in a bag. I am not sure how it comes from the factory as this is also a used antenna. Assembly is easy with this antenna. The elements and boom are marked with different colors. All you have to do is match up the colors and screw them to the booms (Yep, still calling it that), connect the coax and away you go!
I was able to receive some Sats, and hit some distant repeaters with my HT. I also mounted this to my simple TV rotor in my attic and used it with my FT-1900R.
I even did a night time SOTA activation with it. Worked quite well.
- Easy to assemble
- East to transport when assembled
- Dual band
- No duplexor
- Easy to break down
- Can be semi permanent install
- Can accept up to 200w VHF and 100W UHF
- Uses PVC
- Coax has to be positioned correctly to avoid SWR issues
Even though the antenna works and does a great job, The use of PVC just makes me feel that the build quality is… meh. It has a home-brew feel to it, that’s all. When hooking up the coax, you have to keep at least 8″ of the coax 90 degrees from the boom as suggested on their website. In order to get the most out of this antenna, you would have to make some sort of fixture to mount the coax correctly which could be a hassle depending on how you’re looking at it.
Cue the banjos and setup the octagon because we have a fight on our hands. Well… Not really. There is no winner and there is nothing that would make one WAY BETTER than the other. They both have their unique features and they both pretty much perform equally in my book. I like the Elk because it’s not as bulky and can handle more power but I like the Arrow because it doesn’t use Plumbers\Electrical PVC and it’s easy to adjust. If push came to shove and I had to make a choice, I would lean toward the Elk. If they redesigned the boom holder/mount using something other than PVC tubing then I would prefer the Elk over the Arrow.
I decided to make a carrying case for the elk. I used outdoor canvas and my sewing skills are absolutely horrible. But it’s better than the nylon tent bag that was being ripped up by the screws that are sticking out of the boom. Now all the elements are organized and I have a pocket to put coax or a small handheld radio. The green tube in the background is what holds the arrow that was created by the owner of the Arrow. It appears to be a pool stick bag with a PVC pipe. It’s long because at the time, it was one solid length of boom
Here is a photo of both the antennas un-assembled. At the point of taking this photo, the Arrow still has a one piece boom. They both pretty much take up the space if the boom was split on the arrow.
Here is the duplexor that is located within the handle of the Arrow. Wasn’t going to cut the shrink wrap to show the circuit but it’s no secret. the plans are out on the internet.
Here are both antennas assembled. You can see that the Arrow is bulkier due to it’s cross polarization and it’s a bit longer than the Elk. But I will say that the arrow “Feels” lighter. I wouldn’t be holding either antenna for an extended amount of time.
Here is the “Split Boom” modification I did to the arrow antenna. This is available as an option from Arrow Antennas and I would suggest spending the extra money to have it done for you. What’s great is even though arrow sells a split boom model, they published the modification to make your one piece boom into a split. I followed the directions on the site except for the angle. I used a piece of 1/2″ plumbing copper pipe. I should have turned it down in the lathe as it was a really tight fit. Once I got the copper pipe a couple inches in the boom, I drilled a hole through the boom and tube and used aluminum pop rivets to secure the copper tube. Once I got the other end of the boom to slide on the copper pipe and meet the angle, I drilled a hole through copper tube using the hole for the first director element for the UHF side of the antenna. This way when you thread the arrows through the boom and tube, it will “Lock” the booms together. Nice move on arrows part.
Overall there is no clear winner. They both have their strengths and weeknesses. My personal preferance would be the elk even though I wouldn’t mind the arrow at all. Tasters choice I guess.
Thanks for reading!
Even though I have yet to participate in any type of Radio Direction Finding (RDF) event, I find myself buying and building stuff for it. This time I decided to build an offset (active) attenuator as I think it’s a must need for RDF. When I was testing out my 3EL tape measure Yagi, I placed a transmitter on my property and tried to find it with a Yagi and found that it was near impossible to pinpoint the source as my radio was showing full scale and dead full quieting no matter where I went.
Since I’ve been reading a lot about fox hunting, I knew I needed an attenuator. However there are different kinds of attenuators that you can make or buy commercially. I wasn’t sure what to get at the time. I narrowed it down to the offset attenuator and the step attenuator. I went with the offset attenuator because it appears to be cheaper, easy to make and better than a step attenuator.
The attenuator that I went with was found on HomingIn.com’s Website. The article was writen by Joel Moell (K0OV) and explained in detail about the attenuator. What the offset attenuator does is “Offset” the received signal by 4MHz using a diode, oscillator and some other passive components. You are now listening to the signal away from it’s transmitting frequency. Your antenna and radio is no longer being overloaded and you’ll be able to get even closer to the signal.
It appears to be quite easy to build, even for me! So I went with it. The parts that are listen in the article are a little outdated
Here is an updated list of parts that I purchased. I usually use Mouser for components but I wasn’t satisfied with their shipping to the North East so I used Digi-Key with better results
|1X||CAP CER 470PF 2KV 10% RADIAL||$0.23 ea||1286PH-ND||Digi-Key|
|2X||CAP CER 4700PF 50V 10% RADIAL||$0.30 ea||BC2683CT-ND||Digi-Key|
|2X||RES 2.2K OHM 1/4W 5% CARBON FILM||$0.10 ea||2.2KQBK-ND||Digi-Key|
|1X||RES 4.7K OHM 1/4W 5% CARBON FILM||$0.10 ea||4.7KQBK-ND||Digi-Key|
|1X||DIODE SMALL SIG 100V 200MA DO35||$0.10 ea||1N4148TACT-ND||Digi-Key|
|1X||OSC 4.0000 MHZ FULL SIZE||$2.49 ea||CTX774-ND||Digi-Key|
|1X||BNC FRONT MT RECEPT SHORT||$4.67 ea||ARF1064-ND||Digi-Key|
|1X||5K Audio Tape Pot||$3.49 ea||#271-1720||Radio Shack/In-Store|
|1X||Perf Board/PC-Board||$2.49 ea||Radio Shack / Instore|
|1X||SPST Swith||$2.49 ea||Radio Shack / Instore|
Total project cost: Approx $8.00-$18 USD
Making Sure Everything Works
Before putting it on any type of board I wanted to make sure that It works. I never really messed around with making electronic devices from a pile of parts. I put the entire project onto a breadboard following the schematic as close as possible
Here it is being tested out on the breadboard It went together pretty easy. I used a voltage meter to make sure the correct voltage is coming out of the LM7805 regulator. I was seeing around 5V
Here is a video of it in action
Now that I know it works, it’s time to transfer the design to a more permanent home. I wanted to compact it as short as possible to get it to fit into a small PVC box. Since I had a PVC box I wanted the board to go into, I measured a piece of perf board and cut it up
After cutting the board, I laid out all the components and attached all the wiring I could from underneath the board
Here its with most of the stuff attached.
Here is the Top view of the board. I had to use some jumpers (red and green wires) to get some of the components to make contact.
The black wires you see leading away from the board are for power and the adjustable resistor. I tried to test it out at this point to make sure it works before adding the coax and other things but It turned out not to be worth doing. But I did check the circuit wiring a couple times to make sure.
Getting it jammed into the small box was going to be difficult. I knew right away that I wouldn’t be able to fit the 9V battery and the circuit board into the same compartment without using a larger box.
Here is the PVC junction box with the circuit board, switch, POT and cabled jammed into it. I had to have shave some of the flange off on the cover as the Pot is almost the same size as the Inside dimension of the box.
To solve the battery issue, I fabricated a small aluminum box that can hold a 9V battery. I drilled a small hole in the side of the PVC case to route the power cable through. In the above picture you can also see the on/off switch and adjustable pot. I mounted the switch sideways to avoid any accidental switching even though it’s still possible.
Here is the fully assembled antenna. The PVC junction box is also used to mount the grip handle. This way most of the weight is sitting on top of my hand instead of out on the boom. I also didn’t want to put any kind of electronics/metal between the reflector and driven element. Not sure if it would make a difference but I think it’s better off this way
I learned a lot while making this attenuator. The circuit was simple enough to where I can understand what is going on.
If I were to build another one, I would make some changes to make it even better. The big problem is that the coax runs from the driven element straight into the attenuator from inside the PVC. This doesn’t allow me to swap out antennas. What I would do is put a BNC connector sticking out of the PVC box and have the coax come out the boom to make the connection. I could just make an attenuator that is seperate from the antenna but that is just another bulky piece of equipment to carry around. I wouldn’t want to attach it directly to the radio because I think it would put strain on the connector that is in the radio.
You also can’t TX using this antenna. If you do, you can kiss the diode and possibly other parts goodbye. I would try to install some kind of switch that would allow me to TX but I’ll just carry an extra antenna or extra radio for now.
Hopefully it will see a lot of use.
Thanks for reading!
Jeffrey Bail (NT1K)
I’ve been wanting to do a SOTA (Summits On The Air) activation for quite some time and I finally had the chance to go so I took advantage of it. For those who don’t know, SOTA is “Summits On The Air”. Take your equipment, climb a mountain (or hill) with your gear and make at least 4 contacts in order for it to be a successful activation. What’s great about SOTA is that it gets you off your butt and go outdoors. Another great thing about it is that there is a website where you are allowed to self spot so at least others know where you are. After you are done you upload or enter you logs into the website and you can start competing with others in the area and possibly get awards.
In my last article, I made a 3EL Yagi using a tape measure that I didn’t use other than waving it around like a mad man in my back yard. I built the Yagi so I can participate in outdoor activities like radio direction finding and SOTA. So for the past month or so I’ve been itching and looking for any excuse to use this antenna. Nick (K1MAZ) mentioned that he was going to activate Mt. Norwottock after he gets out of work alone. Since my night was free and available, I contacted nick to see if I can tag along which he said sure.
Since this was last second, I ran around the house trying to locate the things that I would think I need for a SOTA activation based off of what I’ve read from other peoples SOTA adventures. I took along my Yagi, Two 2M HT’s, adapters, lots of tape, extra stubby antennas, multi-tool, knife, stuff to keep me warm. Away I went into the dark to drive to “The Notch”.
Here is a map of the State park. The line is red is that path from the visitors center to the summit.
Here is the APRS map of our hike. You will notice that we sort of took a wrong turn. Trail markers are a lot harder to see at night! After we fixed our headings, the climb started and I realized a couple minutes into the “climb” that I am out of shape. I kept stopping, huffing and puffing while Nick was having no issue with the climb. I wasn’t sure if it was all due to being out of shape or wearing very thick clothing .
Once we reached the summit, I was hot to trot so I immediately got the Yagi going and left Nick to assemble his HF wire antenna. I should have helped him but I was a little to excited and wanted to get on the air right away. After making the bulk of my contacts, I’ve stopped to help him finish installing the antenna.
This was the setup that I was using. My homebrew 3EL Yagi and the Wouxun kg-uvd1p handheld.
Since there was cell/data coverage on the summit, I spotted my self on the local clubs FaceBook page and thought I spotted myself on SOTAwatch. Got on 146.520 Mhz (AKA National calling freq) and started calling CQ. As there is little to no activity around here on 146.520, I decided to stay on that frequency as it was not causing any harm. Not even a minute of calling CQ, I was contacted by ED (KB1NWH) from his QTH 22Mi away from my location as well as Mike (N1TA). At the point I was assuming that they and some of the SOTA regulars in the area were going to be my only contacts. I was wrong… One of the people that worked me or saw my post on Facebook went on the local repeater and announced that I was up there. That opened up the flood gates and I worked the following
- AB1RS – Rich
- KB1PWH -
- WD1S – James
- W1MSW – Matt (SOTA Jerks)
- N1FDC – Phil
- KB1VPN – Jake
- K1YO – Bob (Mobile)
- KK1W – Jim (SOTA Jerks)
- WI1N – Charles
- WC1Y – Rory
- KB1JFQ – Chuck (SOTA Regular)
- WW1X – Rockwell (SOTA Regular)
- N1KXR – Rich
A total of 15 Contacts on VHF.
All these people coming out to work me made all the troubles I had getting up there worth it. I was going up there thinking that I wouldn’t have enough contacts to make the activation count but thanks to those listed above, I now have 1 activator point.
I’ve learned a lot by this one trip. The tape measure yagi turned out to be a success! Almost everyone that contacted me on VHF was strong and DFQ.
I plotted out all the contacts I made based on their address on QRZ.com, Two of them were mobile stations so I just put markers to area where they reported they were.
Everyone was pretty much “From The Valley” and all contacts I’ve had were crystal clear. I had a backup two meter radio and I should have used it to compare using the rubber duck to using the yagi but that thought escaped me.
HF Side of Things
Nick was more interested in the HF side to the hike. He brought along his FT100, MFJ Tuner, G5RV and coax. When we reached the summit area, Nick when right to work putting up his antenna in the dark. He didn’t get the antenna as high as he wanted it (8-10ft off the ground) but used it anyways. Once everything was set, Nick spotted then went on the air.
Here is a little video I took.
At first all the locals were calling and then some of the SOTA regulars started contacting him as well.
Between 80M and 40M, Nick had 15 contacts and I had 7.
This was just a quick last minute thing for me so I didn’t have much time to plan. I quickly gathered anything that would fit in my pockets of my cargo pants and was more worried about staying warm than anything else.
Even though the Yagi I was using didn’t weigh much and it didn’t give me an issue during the climb, It started to “feel” heavy while I was using it. Holding that and the radio at the same time made logging contacts very difficult. Not sure if it was me or the cold weather but the radio kept changing frequencies which made things a little more difficult. I am going to modify the yagi so I can put it on a Tripod and I am going to make it so the radio can be mounted to the tripod as well and use a speaker/mic to make contacts.
Overall I had a great time and I want to do it again with VHF. If I keep doing it, I might pickup some portable HF gear.
Thanks for reading
After seeing a lot of articles written about making a three element Yagi using PVC and a tape measure, I was interested but not excited about it. That was until I made a QSO with K1MAZ (Nick) while he was doing a SOTA Activation. I decided to try to make contact with Nick on VHF as it was spotted on the SOTA website. Nick was on top of Burley Hill in Union CT which is about 30mi from my QTH. He tried using his stock antenna on his Yaesu Handheld but it’s just a little too far out of range. I knew someone was trying to get in but there was no copy. A couple of minutes later I hear him again, but it sounded like he was in front of my house. He was S9+ and very clear audio. After meeting up with him I asked what antenna he used and he said that he was using his Tape Measure Yagi. I was somewhat amazed that it worked that well.
Now I want to make this antenna. It appears to be real easy to make and requires only hand tools. I ended going with a mixture of three designs
The first design I went with was from WB2HOL which appears to the origin of this particular antenna. It’s designed to be a RDF (Radio Direction Finding) antenna. It could also be used in portable operations like SOTA or Field Day. I obtained all the dimensions needed from his website.
I got the boom design from the Camden County Radio Society’s website which is slightly different from WB2HOL. It replaced the tee used by the director with another cross tee and added a 5″ stub. I have no particular reason why I went with this book design. I just liked it and it avoids adding a different part even though it’s no big deal.
Finally I got the choke from an article published in QST Magazine (May 2007)
Is the choke/balun needed? I’m not experienced enough to give you a yes or no answer. I decided to use it because it wasn’t going to cost me anything to do it. If it didn’t work our or was causing an issue then I can just simply un-wind it.
I am not going to go into detail about making the beam as it’s already done for you in the those articles that I linked to above.
However I will provide a detailed blueprint that is a little better than what I’ve seen out there.
Please use all safety cautions while working with tools and parts!
I tried as best as possible to get the exact dimensions of the PVC caps and cross tees but I found that the dimensions vary between manufacturers. That will explain the 0.060″ (1.5mm) differnce in element spacing as noted on the print.
Along with the instructions on the blueprint, I would like to share some of my personal experiences when it comes to building and using the antenna.
Working with PVC Tubing
I didn’t have a PVC cutter as I rarely do PVC work. I also didn’t have a vice or clamp setup to use a regular saw or sawzall with. I ended up using a tubing cutter that is normally used on copper tubing for plumbing. It worked but it wasn’t pretty. It pushed the PVC to form a flange or lip around the entire diameter of the tube. I had to use a sander to remove the burr/lip.
PVC Cut into lengths
I also decided NOT to use PVC primer and cement. The parts fit together so tight that I didn’t even bother using it.
Antenna Boom Dry Fit – PVC was so tight fitting that I didn’t bother using glue
Tape Measure Sharpness
The tape measure is somewhat sharp along the long edge. It’s not razor sharp but it’s sharp. Cutting the tape measure creates a real sharp edge. You can combat this by either wrapping the exposed edge with electrical tape or cutting a chamfer (corner) or both. I’m going to use a product call “Plasti-Dip) and coat the tips of each element with it.
Hopefully you will be careful running around with the beam. Doing this will make things just a tad bit safer.
I’d would either dismantle or cut out the bad sections of tape. If you already have a 1″ wide (or bigger) tape measure, I’d suggest buying a new one and cut apart your old one. I’ve notice coating usually wears out within the first couple of feet. My suggestion would be to start cutting the tape up from the oppisiet end.
Soldering the Hairpin and Coax
There is also an issue when it comes to soldering the tape measure. If you have normal flux core solder, you might have a hard time soldering the wires to the tape measure to where it won’t stick. I ended up using a liquid flux that is commonly used in the plumbing/welding industry. It’s an acidic flux that works great.
After grinding away the paint/coating on the tape measure, I put just a teensy drop of flux on the exposed metal of the driven elements. After soldering the hairpin match and coax using a 100W iron, I took it over to the sink and washed off any left over residue that was still on the tape. I’ve been told and I’ve read that using this type of flux is pretty corrosive and will eat away at the metal it was applied to causing a bad connect. So please be careful. After a week of playing around with it, I have not noticed anything.
Running the cable through the boom.
You will notice that I drilled some holes extra holes. I want to run the coax through the center of the boom, have it come out to start the coil and back through. I did that so the cable couldn’t drag across or get snagged in the reflector and to provide a little more security with the coil. It’s not a big deal but I found it to be cleaner than having it zip-tied or taped to the boom.
Cable Through Boom
You can build this antenna for under $20. Since I work in trade where a lot of people accidentally cut off or destroy their tape measures, I have quite the collection of tape measures.
8FT of 1/2″ Schedual 40 PVC Pipe - $3 (Home Depot)
3 PVC Cross Tees 1/2″ – $1.50 Ea ($4.50) (Home Depot)
2 PVC Caps 1/2″ – $0.40 Ea ($0.80) (Home Depot)
6 SS Hose Clamps – $1 Ea ($6.00) (Home Depot)
1 Tape Measure – $3 (Harbor Freight)
Grand Total – Approx $17
If you already have a 1″ wide or bigger tape measure in your tool box, I’d suggest on purchasing a decent tape measure and use your old one for this project. When it comes to using used tape measures, I would make my cuts starting from the other end of the tape. Most used tapes have lots of wear and tear on the first 12″.
Also don’t cheap out and get regular steel and electrical grade PVC conduit. The clamps will rust and the electrical PVC has a thinner wall and will easily flex. It may not happen right away but time will take it’s toll. I know it’s a cheap antenna but it would be more cost effective in the long run.
Well Did it work? I would say so, I don’t have an analyzer to tell you for sure. I hooked up the antenna to a SWR meter (bridge) and was seeing 1.2-1.5 on the meter. I went out in the back yard of my house and I’m sure my neighbors think that I’m training to be a JEDI fighter or something with the way I was waving the antenna around. I ended up hitting a couple of repeaters that I couldn’t normally hit with the stock antenna
Here is a video I made really quick to show it in action
Nothing exciting but it was fun.
Here is the complete setup. I gave myself enough slack on the coax incase I decided to mount the yagi on a tripod.
Overall it was a really fun build. It didn’t require any type of heavy equipment or tedious work. I have a feeling that running around the woods with a tape measure will end up with crimped or broken tape measure. However it would be much better that running around with 1/4″ (6.35mm) aluminum rod. Replacing the director and reflector would be easy as cutting the tape measure. So fart so good!
Thanks for reading,
I am sure some of you have been hearing the letters RTL-SDR come up more often. At the time all I knew was what the SDR part meant (Software Defined Radio) and didn’t really care about the subject. After hearing more and more I decided to see what all the buzz was about.
The company Realtek (sounds familiar?) designed an IC chip called the RTL2832/RTL2832U (USB 2.0) that was originally used by electronics manufacturers that made DVB-T (Digital Video Broadcast - Terrestrial) receivers. These devices will display Digital TV signals from nearby TV stations (Remember the whole Digital TV upgrade that made older TV’s useless unless it has a converter) as well as digital FM radio onto your computer/laptop. The actual RTL chip demodulates the signal, cleans it up and processes the signal using a built in ADC (Analog to Digital Converter). All the software does is display the information that is coming out of the RTL and it will also control the frequency and filtering of the signal through a tuning chip on the board. It’s way more technical than that but I’m just giving you the basics.
Someone found out that RTL chip with the tuner could allow you do sample/listen to signals from 64Mhz up to 1678Mhz (Varies depending on the tuner) which is quite impressive. These chips could also decode many different modulations and you can view/sample megahertz at a time. All of this for around $20 USD and some software. With some other tricks you can decode APCO25 (P25) or other digtal and digital type signals with this dongle.
What does all this mean to me?
In short terms you have a Software Defined Receiver (SDR) that you can listen and actually SEE any signals from around 64Mhz to around 1678Mhz at around 2Mhz at a time.
For example you can listen/watch a good portion of the 2M (Let’s say from 146.000-148.000Mhz) band and see all the conversations going on in that 2Mhz span. Depending on the software you’re using, you can filter just what you want to hear while seeing what else is happening . If you’re listening to a repeater, you can view the station on the input as well as hear and see the same station on the output frequency on 2M. If you tried to get the same features in a police scanner, you could be spending at hundreds of dollars.
Is this too good to be true? What’s the catch? Is this a Scam?
It does seem to be too good to be true but it’s actually true. For around $20 USD, you can have a VHF/UHF SDR receiver. I have a feeling the price will go up as retailers are seeing a huge increase in sales of these “Cheap” devices. There are some catches however. It doesn’t have the best filtering so signals could get cross and mixed in. You’ll sometimes hear “Birdies” and there are times where the frequency displayed is not correct to the frequency you’re listening too (So far I’ve seen if off around 6khz). Another issue is with the dongle itself, depending on the manufacture the cases don’t have really any shielding and the antenna connection and the supplied antenna is basically crap. At the time of writing this, there are a couple companies seeing the demand for these RTLSDR’s and are making units with the correct case and antenna connection. But for the issues it has and for the price they are being sold at the moment, it’s well worth having. It’s almost comparable to purchasing a FunCube dongle for around $190 that is similar even though I think the FunCube is better and helps support AMSAT.
Ok ok ok… You’ve sold me. How do I get one these $20 dongles?
This should be the only battle you have to do. Securing the Proper Dongle at the correct price. There are many manufactures of dongles that do almost the same things. You want to find a dongle with the correct RTL chip and the correct tuner chip. The Cat’s meow of Chipsets are the RTL2832U and the Elonics E4000 (AKA E4K) tuner chip. Why? I have no clue. Some dongles have this configuration and some use other Tuners like the Fitipower FC0013 and FC0012 that work also. Some of the differences are the Bandsplit of what frequencies the tuner chip can tune.
At the time of writing this, If you can get your hands on a EzCap EzTv668 (or EzTv666) with the RTL2832U and E4000 tuner then you are golden. However the company that designed and manufactured the E4000 is no longer in business and the company is now being liquidated. This means at this point in time the E4K is no longer being produced. Most companies are switching over to the FITIPOWER FC0013. So you want to make sure that you are getting a unit with the E4K. There are some ebay sellers that are claiming to ship dongles with the E4K but they are really the FC0013.
If you happen to get stuck with one, don’t worry. It will still work.
JUST TELL ME WHICH ONE!!! Grrrrr.
That’s the thing… I can’t! Things are changing so much that its possible for something to be different next week. Have no fear! The good people over at /r/rtlsdr over at Reddit.Com (http://www.reddit.com/r/RTLSDR) have a very nice up-to-date list of dongles as well as places to purchase these dongles. Just take note that you’re still gambling when purchasing a Dongle. A lot of these are drop shipped from China and you’ll never know what you’ll get until it lands on your doorstep.
Here is a Ebay “EzCap EzTV668″ screen shot of one I actually purchased on Ebay.
(Click to enlarge)
I purchased this from a seller on Ebay as well as one from Deal Extreme (DealExtreme.Com). The reason I purchased it from Ebay is the one I ordered from DealExtreme was taking way too long and when I contacted their customer service, I was told they were out of stock and could take almost another month for it to come in.
If you notice the Ebay Auction says RTL2832U and E4000 tuner… Well… This is what I got!
It’s a EzTv645 and it has the Fitipower FC0013. This dongle is NOTHING like the advertised dongle on Ebay.
I could have complained and returned it but as you can tell, I hacked it up already. I just wanted to warn you that you might not get what is advertised on Ebay.
I added a Pigtail with a PL-259 which voided any warranty (if any) it had. I wasn’t going to waste time with trying to return someone that was sold over ebay and shipped from china.
When soldering on the coax to the board. I messed up and used a powerful (too powerful) soldering iron without any grounding or ESD protection.
Here is a Video of the dongle with the FC0013 in action
You’ll see some of the signals being mixed and some other horrible stuff.
I am not sure if this is how it is normally is or damage done from my soldering job.
Also for some reason the video lost sync with the audio.
The dongle still works but it’s in the hands of my co-worker who would really have fun with this.
The very next day after screwing up the Ebay EzTV645 purchase, My order from DealExtreme showed up
After reading posts on Reddit of people saying their recent DealExtreme orders have the FC0013 tuner got me a little bit worried. I opened the dongle and is happy to see this
This is what you’re looking for. It’s the advertised 668 with the Elonics E4000 Chip (Little square chip to the right of the Antenna Jack) and the RTL2832U (Under the IR Sensor).
I dared not to touch this one with a soldering iron. For now I went to Radio Shack and got a couple connectors (PAL to BNC). I would suggest going on ebay and getting the correct adapters or if you have a really good soldering station, solder in a SMA pigtail and/or connector.
Here is a video of the new dongle
It looks and sounds much better than the one I purchased from Ebay. But I can’t tell you for sure since I hacked up the Ebay one before I can make a comparison between the two.
The hardware finally came in… What now?
You now have to obtain software to display the information from the dongle. At this point while writing the article, the best choice for RTLSDR software is SDR# (SDR Sharp). There are others out there depending on the operating system you are running. I’ve chosen SDR# because it’s really easy to setup and use (compared to some of the others) and it works on some other SDR hardware I have. Plus IMO it’s best choice for beginners like myself. If you do end up using SDR#, make sure to download the DEVELOPMENT (DEV) Version as well has ZADIG which will replace the driver that was automatically installed (or attemped) when you plugged in the dongle with the one that is needed to run in SDR#
I would follow these instructions as it’s worked for me
That’s It!! It should be working. Tune around and have fun. If you’re using the antenna that came with the dongle, good luck! You will not pick up much with the stock antenna. I ended up cutting the plug off the antenna and soldering it to some RG-58 as to not mess up the board. You can also find adapters online and possibly at Radio Shack. The plug looks like an RCA but it’s really a “Belling Lee” (IEC 169-2) connector or PAL connector.
Here are some RTLSDR websites that were helped me out and are resources for this article.
Http://www.reddit.com/r/RTLSDR – Huge community with tons of information on the dongles that are being sold
http://sdr.osmocom.org/trac/wiki/rtl-sdr - RTLSDR website with more technical information than I’ll ever know.
http://www.rtlsdr.com/ - Just catalogs RTLSDR feeds from websites and video sites.
http://www.sdrsharp.com – Website for SDR#. My personal choice for SDR software
Possibly where the RTLSDR idea came from
Just want to say thanks to all those on Reddit.Com (/R/RTLSDR and /R/amateurradio) and those on ##RTLSDR and other IRC channels on freenode/geekshed for helping me out.
Even though Field Day (FD) is weeks away, the planning of it gets me excited knowing that it’s near. Field day is the basically the main reason why I got my license. During my CB days, someone brought me to a field day hosted by the MTARA (Mount Tom Amateur Radio Assn.) on top of Mount Tom around 1995. I recall being on 14mhz using a Kenwood TS-440 and was making contacts all around the country. Compared to CB I was amazed about the contacts I was making considering I would never hear the stations, let alone make contact with them on CB. Field day was the kick in the ass to get my license and pretty much put CB behind me.
For those who don’t know what Field Day is, I would check out this website that would explain it in more detail then I could. It’s a emergency preparedness exercise where operators try to contact with as many other operators as possible. Even though you don’t have to, it’s encouraged that you bring your gear and communicate from a field, hence “Field” Day. A lot of local Amatuer Radio Clubs put on events related to FD to have fun and also promote Amateur Radio to the general public at the same time.
Last year I participated in Field Day with the Hampden County Amateur Radio Association running the digital station.
This year I will be running SSB on 40M (7mhz) with the HCRA again at Dufresne Park in Granby MA. If you are in the area. You should stop by and check it out. Go Here for more information
As this blog is geared to newer hams, you’ll sometimes hear the word “contesting” or “radio sport”. Sometimes I think it’s funny seeing or hearing Ham Radio and sport in the same sentence. It reminds me of a scene in the movie “King Pin” where the character played by Randy Quaid says, “It’s intimidating to be in the presence of so many great athletes.” Then the shot pans to a bunch of fat guys smoking, eating and drinking. Sort of an oxy-moron if you ask me.
So what is this “contesting” and what’s it about?
As simply as I can put it, Contesting is where a operator or operators try to establish contact with as many other operators as possible within a certain period of time. What makes each contest unique are the rules and regulations that govern each contest. Most contests have the operators send a piece of information to the other operator and vise versa. This “Exchange” is used by sponsor of the contest to ensure that an actual contact actually happened. Once the contest is over, all the operators that took part in it will send in their logs to the sponsor before a deadline. The sponsor will then enter all the logs into a database and it will cross check all the logs and award points. The points are awarded depending on the rules of the contest. It can be as simple as one point per contact or 2 or 3 points. There are also Multipliers (mults) which are defined by the rules of the contest, making contact with a mult will multiply your entire score by that amount.
The one with the most points wins is a general way to put it. Depending on the contest, there could be multiple winners for all the different categories they have. Some of those categories could be QRP, Low Power (>100W), High Power(<250W), Emergency Power, Single Operator, Multiple Transceivers with Multiple Operators, Single Transmitter with Mulitple Operators, Rover/Portable (Driving around) are just some of the categories that could be used in a contest. Just read the rules of the particular contest and you will know where to fit in or what to aim for.
Is contesting for me?
That all depends on you. Some operators love it. They eat, drink and don’t sleep contesting. The only time you will see them on the air is during a contest. There are even clubs dedicated for contesting. I belong to the “Yankee Clipper Contest Club” (YCCC) and they take contesting very seriously. If you are into contesting I would suggest to join one. As I did with the YCCC, you can learn a lot about contesting . It’s not necessary but If you get bitten by the contesting bug, the information and help from fellow members is worth the membership fee.
Some of the operators who do a lot of contesting, setup their stations with only contesting in mind. Some ops go as far as buying property and building their station around contesting.
I had a chance to visit one of these contest stations and I was quite impressed with the setup. The station I got to visit is built and owned by Dave Robbins (K1TTT). I got to operate at his station with the BSA Venture Crew 510 (NE1C) for both the North American QSO Party (NAQP) and WPX SSB.
Here is what is station looks like
Pictured: John (Kx1x) and Nick (K1MAZ)
You’ll notice that there are multiple transmitters scattered throughout his station. Each area is basically dedicated for a single band. If the contest allows, there can be 6 to 9 transmitters being used at the exact same time. The software (N1MM) that is being used is networked throughout his entire shack. This will show real time progress of the contest and predict a very accurate score. It could also lead to a little contest between operators to see how many QSOs each operator can make.
Here are some of the Antennas that make this station possible
I didn’t have time to take photos of all of his antennas but it’s quite impressive. If you want more information about K1TTT, you can visit his website.
With this Station/Setup, It’s NOT hard to have a high score. Since this is what is considered to be a “BIG GUN” station, it’s easy to take command of a frequency and “Run” for a good portion of the contest. Let the contacts come to you. The only thing I did not like about using his station is when I returned home to use my equipment only to hear a fraction of what I just heard at the contest station. But if you ever have a chance to use a contest station, go for it! You can learn a lot about contesting just by watching someone who has done it for a while.
Now don’t let me scare you out of contesting by saying you need to have this “BIG GUN” station. The truth is a lot of the stations that participate in contests have what is considered to be a “Normal” setup. If you’re still on the fence about contesting, my advice would be to find someone or a group within a reasonable distance and shadow them for a contest. If you join a contesting club (if it’s possible), there are contesters who are looking for more operators as they work in “Shifts” depending on the contest. Another thing you can do is wait for Field Day. Even though the ARRL calls Field Day a emergency preparedness exercise, it’s could be considered a contest or even both. You get points for making contacts and points for doing certain things and they publish the results every year. Visit a Field Day site and you will get a general idea on how it works. If you don’t want to transport to another station, as long as you have the equipment, there is nothing to stop you from contesting from your home (other than your license limitations).
The Dark Side of contesting
Not all Hams enjoy contesting. Actually some Hams just flat out HATE contesting and anything to do with it. Some of them beleave that contesting actually ruins amateur radio because it’s turning a leisurely hobby into a “Sport” and it’s congesting the airwaves with nothing but false exchanges transmitted by operators who are over-driving their signal and using more power than the legal limit to force other ops off the frequency and/or band. You’re not learning about the person on the other side, you’re just establishing contact and moving on.
That is basically what you will hear from the “Anti-Contesters” and I think it’s a half truth. There are operators that show no respect and do all of those things. But it also happens when there is not a contest going on. When a major contest is going on, depending on the contest, there is a lot of activity going on. There is so much activity that it’s very possible that the entire band is being consumed by contesters. There is refuge from all this chaos however. Most, If not all contests do not allow contesting on the WARC bands (60m, 30m, 17m, 12m) so if you don’t like contesting, you can use these bands. The downside to the WARC bands is that you have limited space and there are not many antennas designed for the WARC bands which keeps some operators off.
Most contests take place during the weekend. A good amount of the contests are mode specific. So if it’s a RTTY contest, most of the activity will be around the RTTY calling frequencies and the SSB portion will be not effected. Same with CW or PSK or SSB only. However there are contests that any and/or every mode can be used.
If you’re an avid “Rag Chewer” contesting might not be up your alley. Don’t knock it down until you at least put a serious effort into contesting. If you’re going into contesting with a negative attitude, you’ll have negative results. If it ends up that you don’t like contesting for whatever reason, please don’t turn into a “Anti-Contester”. Just because you like telling your story to every ham that you come across doesn’t mean that every single amateur radio operator should be doing the same thing. Some hams are in it for CW, some are in it for Ragchewing, some are in it for chasing DX, some are in it for EmComm (Emergency Communications), some are in it for contesting and yada yada yada ya. Ham Radio is a big melting pot of all different types of people and the different ways they communicate. It shouldn’t be subject to a single use.
I want to try contesting, what do I need?
As I stated earlier, you don’t need a “Big Gun” station to participate and have fun in a contest. All You need is time, will and determination more than anything else. Oh and at least some equipment. If you already have a transceiver, antenna and a way to log the contacts then you are all set for contesting. If you’re comfortable with just that then hopefully you’ll have a fun time contesting.
There are things out there that will make your contesting experience much more enjoyable and will give you a better chance of a higher score. In my personal opinion, the biggest contribution to contesting is the personal computer. With that and CAT control and possibly an internet connection, it will make you much faster in the contest. With a computer you can use logging software in combination with rig control to log the frequency, time, call-sign and exchange. Depending on the software, it will estimate your score. That depends on if the other stations you’ve contacted submitted their logs.
Some other things that can help you in a contest are a Headset (For SSB) with either a foot switch or the VOX (Voice Operated Transmission) enabled on your radio (if you have one). That will free up your hands for logging and other things. It will also block most of the noise happening in your environment. A memory keyer (CW/SSB/Computer) would be beneficial for both CW and voice contesting. What the memory keyer does is store messages that you will be sending over and over again. For example if you say “CQ Contest CQ Contest This Is November Tango One Kilo Contest” hundreds or thousands of times throughout a contest, it can get tiring and you’ll sound horrible towards the end of the contest. The memory keyer will store the message and play it over the air whenever you push a button. So you can store things like CQ, Your exchange (if there is no serial number involved or anything that is different per contact), “Thank you, 73″, “QRZ This is NT1K” and other things that you might say repeatedly. Same with Morse code. A lot of this can be done with the computer. However, you might have to add an additonal piece of equipment called a “Sound Card Interface” like the Rigblaster or SignaLink for voice and/or some kind of CW interface like WinKey. You can also just buy the hardware (linked earlier). There are many options out there, some people use a couple of Audio cables and the VOX on their radio as an interface.
In short, a ideal contest setup would consist of your transceiver(s), antenna(s), computer w/ appropriate software, headset and/or memory keyer (either software or hardware).
I have what I think is needed for contesting. What do I do?
First off, see what contest(s) are out there that you are interested in and see when they happen. This website catalogs the upcoming contests and gives you the basics about each one. Most contests have a website that is dedicated to the contest in question. I would visit that web site, read and understand all the rules for that contest. Nothing is more embarrassing then not reading the rules and participating in a contest where all the work that you did could be flushed down the toilet.
Next thing to do is to set your goals. You can aim to beat your last years score, the score of a rival operator or operate for X amount of time or X amount of contacts. You can aim really high and set your goal to WIN the contest.
If you are brand new to contesting, I would read the rules and listen in on a different contest before taking part in the one that you’re interested in. That way you have a feel for what’s about to happen. If you’re in a contest that is using a “Digital” mode (such as RTTY, PSK, CW, FeldHell, etc.. ) it would be wise to setup “macros” or scripts needed for calling CQ and making exchanges. Nothing is more irritating when you’re in a PSK or RTTY contest and the persons macro is a mile long causing the QSO to take way longer than it should.
About a week before the contest begins, start checking your equipment and software to make sure everything is in working order. That way you’re not running around like a chicken with it’s head cut off looking for hardware to replace your non-working hardware or trying to fix the software you’re using.
The day before the contest starts I would check your equipment again and configure your software (if you’re using it) to the contest that you will be participating in. If you’re using rig control, make sure that it works and everything communicates with each other. Then I would test your setup by getting on the air and making contacts. If you happen to have towers and beams or directional antennas, have them pointed in the direction you need them in.
Get a good nights sleep. You don’t want to be exhausted when getting into the contest. Depending on the contest, you might NOT be sleeping for the next 48 hours. So plan accordingly. Hours before the contest starts, I would do one final check of you’re equipment. Depending on how serious you want to be, I would also take this time to setup your area. Make it as comfortable as possible since you might be planted there for a long time. Things like having a stocked cooler and/or coffee maker within arms reach can really make things easier. Same thing with snacks and/or meals. If you’ve ever done gaming then you should already have an idea of what it’s going to be like. This may sound extreme but that’s how some people do it.
Contest Started. What do I do?
To answer that easily… GO GO GO!! What are you waiting for?!? Start!.. Every couple seconds of just sitting there wondering could cost you points. The ideal thing to do would to take command of a un-used frequency (good luck) and start calling “CQ contest…” (running) and start racking up those contacts. However depending on the contest, you might get pushed off by the “BIG GUNS”. It’s happened to me (even when I was using a “BIG GUN” station) a lot and I am sure it will happen to you. It’s hard to compete when the “Big Guns” are hogging up the band. Don’t let that make you lose hope. Use that to your advantage. Work all those “Big Gun” Stations and do what it called “Search & Pounce (S&P)”. Start from the beginning of the band and turn the dial towards the end of the band, working as many stations as possible. Depending on the contest or the rules or the category you’re running in, once you reached the end of the band, go the next higher band and do the same thing over and over. If you happen to find an empty frequency that can be used then stop S&P and go back to Calling CQ (Running) and repeat.
Another way people contest (if it’s allowed in the contest) is to utilize the Spotter/Skimmer/Packet networks that are out there. For those who don’t know what this is, it’s the exact same thing as a “DX Cluster”. What happens during the contest is after the operator makes a contact, the frequency and callaign will be “Spotted” on the network. For CW there are computers that use SDR (Software Defined Radio) that can look at almost 200Khz worth of bandwidth, decode the CW and post the spots on the cluster. They call this skimming. If you have the appropriate software and it’s setup correctly, you can have all this information displayed on your computer and all you would have to do is click on the callsign you want to make contact with and it will automatically put you on the frequency they are on and partially fill out the log book. The downside of this is that it could possibly put you into a different category. It’s may be fine for some contests (because you’re already in that category) but will make it difficult for you to even place in other contests because there is a possibility that you will be lumped in with the bigger stations.
What can I do to have the Highest Score Possible?
Well, that depends on you and your will, determination and the goals you set before the contest. If your goal was to operate for at least a couple hours and you did then your Goal has been achieved and your score will reflect it. However there are things that you can do to get the highest score possible. The fastest way to a high score is to work multipliers(mults). I brushed on this earlier but depending on how the contest is setup and governed, certain stations are considered multipliers. If you work that station and get confirmation, your score will multiply by that amount. So if you worked 54 (1X) multipliers, each contact (QSO) would be 54 points. If you’re working assisted and depending on the logging software, it will tell you that you’re working a multiplier and your predicted score will change.
Another thing to do is stay active. Some people are only active when the band is “Open” and go off to do other things when the band dies down. Spend some time before the contest looking at and learning HF Propagation charts (Link 1|2|3|4). Make a print out of what bands will be active at certain times and try to get on before the band “Opens” up. Hopefully that will give you a jump and possibly a running frequency. If the contest involves working stations in Europe, you most definitely want to be on the air when the band opens up to Europe due to the massive amount of stations and countries in that area. If the contest is a “work anyone anywhere” type then when the band dies down, concentrate your efforts to working contacts in your area/country. There might be a time were it seems dead. At this point find the most “Active” band and setup camp calling CQ. Contacts will come trickling in but it’s better than not making contacts at all. I also have either my laptop/tablet/smartphone going so I can be doing other things while calling CQ and stopping to make the contact.
Quick Notes On Contesting:
- Set your goal – Is it to be on for X amount of hours? or to make X amount of points? or to beat last years score? or to WIN!
- Check Check Check your equipment – Don’t want to spend the first 3 hours of the contesting fixing things.
- Be comfortable – Setup the area to be as comfortable as possible. Possibly have food and drinks within arms reach.
- Know band openings\closings – Use HF propagation prediction software/sites so you know when a band is opening/closing
- Three tries – If you can’t get the station within three tries, move on or say “Sorry, I can’t work you, please try again later. QRZ” . If they are strong, the chances of them of being there on your next go-around will be high.
- No Ragchewing – The point of a contest is to make as many QSOs as possible. Talking to another contester will end up costing you potential contacts and will annoy the other contester.
- Start low and repeat – If you’re S&P, start at the beginning of the band and work your way to the end. At the end, move to the next band higher until you’re high as you can get and then start over at the lowest possible band and repeat. Like a cirrrrrrcle.
- Follow the DX Code of Conduct – Even though this should be followed at all times. It’s more important during a contest. Not everyone follows this but after some time contesting, They stick out like a sore thumb and will be labeled a LID (poor operator)… Don’t be a LID.
- Keep going - Make as many contacts as you can within the time period you’re allowed. Try to stay at your station
Contest is done… Now What?
After you recover, I would glance over the logs to see if anything sticks out that is wrong like invalid callsigns or bad exchanges and see if you can fix them or possibly remove them (I would try to fix them). Some contests will give kudos to those whom submitted error free logs.
After checking the log, export it in the format the sponsor asked for (mostly carbrillo format) and check the rules of the contest to see how or where you have to submit/upload/e-mail your logs to.
Even if you were in the contest for 10 minutes, If you made contacts, I would submit a log file. There is no FCC Law saying you have to submit a log, but depending on the contest, it might take points away from the other operators since it’s won’t be a true contact since there is no confirmation from you. So if you take part in a contest, please submit a log. Even if it doesn’t benefit you. It’s just good practice.
Was it worth all the time and trouble?
Once again, that all depends on YOU! Did you have a fun time? Did you reach your goals that you’ve set before the contest started? Was this your first time participating in this particular contest? Did you end up getting a certificate or winning a category? All of these questions will tell if you if it was worth it. A great thing about contesting is that you can use the contacts that you made during the contest to count towards awards like DXCC or WAS (that is if you were using YOUR callsign). And if this was your first contest, now you have a base to set your goals for.
NT1K Experiences in Contesting
At the time of writing this article, I’ve participated in a few contests. I am nowhere near being an “expert” at contesting and I don’t have what is considered to be a “BIG GUN” setup. I’m writing this hoping to drum up at least some interest in contesting from those who are just getting into the hobby. There are other articles by veteran contesters that are much better. If you have the chance to join a contesting club, go for it! If you didn’t learn anything from joining and participating in a contest club then I would question what type of club it really is. Some clubs even hold “Contesting Classes” where they will walk you through the details of contesting. You can also attach yourself to a group within the club (and hopefully near your QTH as well) and shadow them to see how it’s all done. Some of these contesters are begging for ops to come over and operate using their callsign (or club call) so they can take a break. Some are willing to teach you (isn’t really hard to say you’re 59 and the exchange) so they can have a semi warm body at the radio making contacts.
My Contesting setup is made up of the following
- Transceiver: Yaesu FT-950 HF/6M - It’s no K3 or IC-7800 but I like it!
- Personal Computer: Quad-Core @ 3.2Ghz using Dual boot Windows 7/Ubuntu
- Software: N1MM Logger, MMTTY(RTTY), FLdigi(PSK) and Ham Radio Deluxe. MMTTY and FLdigi works within N1MM
- Soundcard Interface: SignaLink USB. This is used so I can send Voice CQ and AFSK from the digi programs
- Headset: Heil Pro Set
- Antenna(s): G5RV, ButterNut HF9V (Not Used Yet)
- Amplifier: Heathkit SB-200 w/ 600w out (Not Used During a Contest…Yet). This is optional and can change your category
Contests I’ve actively participated in (So Far)
- Various Field Days (1995-2011) – Even though it not considered to be a contest, I think it is! Field day with the MTARA, PRA and HCRA
- New England QSO Party (2011,2012) – Actually won a plaque for winning first place in Hampden county in 2011. It also means that I beat 6 other ops. Doesn’t matter, still won. Single Op from home using low (1oow) power, submitted as high power by mistake.
- CQ World Wide SSB (2011) - 144,026 points. Would have had more if my power didn’t go out (Oct storm). I’m still getting logbook of the world confirmations from this contest
- CQ World Wide CW (2011) – 12,000 points. My goals were to make 100CW contacts which was achived. I used a computer for the contest so I was only able to make contact with strong stations that were also using a computer. This contest gave me a push to learn CW
- ARRL 10M contest (Dec, 2011) – Approx 8,000 pts. Spent only a couple of hours operating as I don’t have very good 10m coverage (Dipole in attic)
- North America QSO Party – (Score Unknown) Participated in NAQP from K1TTT contest station using the call NE1C.
- CQ WPX SSB – Approx 10,000,000 points. Multi-Op From K1TTT using call NE1C. Was the only op on the night shift for the second day. It was a slow night making abt, 100,000pts but when Europe opened on 20M, I made around 1,500,000 points in the first couple hours. Had a great time, I wish it was my call being used from the stations. I worked countries that I never even heard (Thailand, Mongolia) from at my QTH.It was pointed out that there is more pride making contacts from your home QTH and your setup which I fully agree.
(ARTICLE STILL UNDER REVIEW)
Okay, enough of UHF/GMRS antennas. Now it’s time to step it up (just a little bit) and fabricate a bigger antenna.
Due to material, I decided on a 5 element Yagi built for VHF since all I would have to buy is more 3/8″ round stock. I’ve taken what I learned from the GMRS Yagi and applying it to the design and fabrication of this VHF Antenna. I am writing this article in a way in which I hope newer hams can understand, build and learn about antennas. So please excuse if I go into details about things that you consider simple and “common sense”.
In order to design a Yagi we have to learn what a Yagi is. A Yagi is a Directional antenna made of up elements.
The 3 Major parts which make a yagi are the driven element, reflector and director. When cut and placed at a calculated distance (On a Boom), the elements will cause the RF (Power) to be sent (radiated) or received in whichever direction the antenna is pointing to. In the radio world this is a great because you can basically “Focus” the power and direct it in the direction you want. Whereas a Vertical (Omni-Directional) radiates its energy in a 360 degree pattern (think of throwing a rock in a still lake and watch the ripple pattern in the water.) which will send out your signal “everywhere” but will dissipate quicker.
On the lower frequencies (HF), a Yagi would be the antenna of choice by Hams. Well then how come every ham doesn’t have a Yagi (on HF)? There is a couple of down sides to having a Yagi or Beam antenna (on HF). First off, HF Yagis are huge. In order to use a Yagi/Beam to it’s fullest you would have to install an antenna tower/mast and rotor. HF Yagis are expensive and so is the tower and rotor, so the parts alone could add up to couple thousand dollars. I’ve seen cases where someone moved or is SK (Passed on) and sold their equipment cheap. There are also several other factors that would steer someone away from a Yagi. Those factors could be age, housing restrictions, living in an apartment, permits, handicap, property size, neighbors, and more stuff than I list. However the Yagi I’m building does not take much space and could be transported to be used in events where I am portable. Yagi’s come in many different sizes depending on the frequency and the efficiency of the antenna. The lower the frequency, the larger the antenna. The higher the frequency, the smaller at antenna. The length of the antenna will vary depending on how much efficiency/gain you want. Increasing the length (boom) and adding more director elements will increase the gain/efficiency of the antenna. On the Yagi that I am building, the design is based on the length of the (boom) antenna rather than the gain.
So you want to build a Yagi. To start off your going to have to know what material your going to be using. Most Yagi antennas are built using Aluminum since it’s light and is a great conductor (Well, compared to steel/stainless). There are many different types of aluminum and I would say that 6061-T6 Aluminum would be the best choice for antenna building. The reason is that 6061-T6 is more weather durable and easier to work with compared to other aluminums. The downside of 6061-T6 is when it comes to bending. 6061-T6 tends to crack when bending using a tight radius. Since we’re not bending anything on the yagi we’re building then It won’t matter. If it comes to other designs of yagis that use a Hairpin or folded dipole then I would take the type of aluminum into consideration.
Okay, we’re using Aluminum. What’s next? Now we need to figure the sizes of the material we’re going to use. This all depends on personal preference. For HF Yagis, you’re going to need Tubing ranging from 2″, telescoping in diameter down to 1/2″ because the antenna is going to be big and will need to support the weight of the elements. Since we’re dealing with smaller VHF/UHF antennas, the material doesn’t have to be large. For the antenna that we’re building we will be using 3/8″ (.375″/9.5mm) round solid aluminum and 1″ (1.00″/25.4mm) square tubing to mount the elements to. You can also use 1/4″ solid round aluminum instead of the 3/8″ to save a couple of dollars but realize that it’s easier to damage 1/4″ rod. If you decide to go with 1/4″ round please note that the dimensions and calculations you see in this article will NOT work using 1/4″ rod because 3/8″ rod has more surface area for the signal to travel on and all the calculations are made with 3/8″ In mind. You can change it to work with 1/4″ which I will cover later on.
Now that we have the material and size in mind that we’ll need, we now need to know what frequency we want to transmit on. Since this is a VHF yagi that we’re building, it will most likely be in the 144-148 range. Are you going to use this antenna for sideband (ssb/usb) only, or both ssb and FM (repeater/general operation)? Reason I ask that is if your designing this to be on sideband only, you will only need it to design it to work best over the span from 144.000Mhz to 144.500Mhz whereas FM would need to be designed over the entire band (144.000mMhz to 148.000Mhz). Since we’re building an antenna for the entire 2m band, we going to use 146.000Mhz as the design frequency since it’s directly center of the band and would allow for a somewhat even performance throughout out the band.
Another downfall of the Yagi is that it has a narrow bandwidth.What I mean is that the antenna will work the best over the span anywhere from 100khz to 10mhz depending on the design (Could be more or less). If you start transmitting out of that span, it could create signal loss and high SWR causing the transmitter to step down power to prevent damage (or actually damage older radios). Why build an antenna that is not going to radiate the power going to it? If the antenna is designed and fabricated correctly and you have at least a SWR Meter/Bridge then this should not be an issue.
So now we have everything we need to start designing a Yagi-Udi Antenna. Well… How do you design one? This is a fork in the road and there are many different ways you could design one (too many to list). There are different programs for different types of Yagis and there are different mathematical formulas for different (or the same) types of yagis. The method I am going to use is a Antenna modeling (software) program called 4NEC2. This program is based off the Numerical Electromagnetics Code for modeling antennas. The great thing about 4NEC2 is that you can model almost any antenna and the best part is that its FREE! What this software allows you to do is to design/draw an antenna using X,Y,Z Coordinates and then run the antenna through a simulator to see it’s efficiency, SWR, impedance and many other things that I have yet to look at. Basically it will tell you if your antenna is going to work and how well it will work on or near the frequency you designed it for. Another great thing about 4NEC2 is that it will perform adjustments on your antenna to optimize it for the best results. So if you are somewhat close to a good antenna, the software (if the programed right) will make it even closer. This software however is slightly (or very) difficult to use for a new person in the hobby. I adapted to the design portion of the software because I have knowledge in CAD (Computer Aided Drafting), but I had to do a lot of reading about the electrical properties and how to make the software do what I want. I am not going to dive in depth explaining this software. However, I will show you how I used the software to create the antenna. If you find the software to difficult then skip the section and use the final results in building your antenna.
Before we start using the software, we’re going to need to know what dimensions to input in the software. We can’t just throw random numbers into the software and expect magic to occur and produce the “Perfect” Yagi antenna. The U.S Department of Commerce and the National Bureau Of Standards released a document which helps in Yagi Design. Information based off the manual has lead to the following Dimensions
300 (speed of light in meters)/146.000(mhz) = 2.0547 wavelength or(WL) (in meters). This will be used as reference for the following dimensions.
Length of each element as follows:
Reflector Length = 0.493 X WL=1.01297m (or 39.880″)
Driven Element Length = 0.473 X WL = 0.971873m (or 38.262″)
Director 1 length = 0.440 X WL = 0.904068m (or 35.593″)
Director 2 length = 0.435 X WL = 0.893795m (or 35.188″)
Director 3 length = 0.430 X WL = 0.883521 (or 34.7843″)
Spacing of each elements from the reflector as follows (WL = 2.0547 in meters)
Reflector to Driven element = 0.125 X WL = .256838m (or 10.1117″)
Reflector to Director 1 = 0.250 X WL = .513675m (or 20.223″)
Reflector to Director 2 = 0.500 X WL = 1.02735m (or 40.446″)
Reflector to Director 3 = 0.750 X WL = 1.54103m (or 60.670″)
Now that we have all the dimensions that will put our Yagi in the “Ball Park” of a good VHF Antenna. The software will end up fine tuning the elements and spacing between elements to obtain the best SWR for the giving variables (i.e Element diameter, Boom length and etc).
Open the 4NEC2 and plot the antenna using the dimensions above. At some point in the near future, I will post a video on how I plotted the antenna. If you don’t know how to use 4NEC2 I suggest searching using google for results because that’s how I learned.
Please note that using the “Optimization” will give different results what I came up with. So do not get alarmed or worried. If it was done right then there shouldn’t be any issues to the design that the software gave you. DO NOT START CUTTING ANYTHING!! These dimensions will change!
Here are the Dimensions and spacings from 4NEC2 that I got! (Note that these dimensions will be the ones used for the rest of the article and that they will be different than your results if you decided to use the software)
Spacings (Each from the reflector)
Now you should have all the Dimensions (lengths) of the elements and the spacing. Now we need to work on the BOOM. The Boom is the tube that we are going to mount the elements on. At this point we have to decide what material, size and length we’re going to use for the boom and how we’re going to mount the elements. I have decided on 1.000″ square aluminum tubing because it’s commonly used and that it’s easier to work with compared to round tubing. The length that we’re going to need is based on the location of your last (furthest away) director.
I also decided to mount the elements by drilling through the boom and using plastic shoulder washers so we can slide the elements through the boom without the elements contacting the boom. At any point we DO NOT WANT THE ELEMENTS TO CONTACT THE BOOM!! Because we’re putting the elements through the boom, the elements will become electrically shorter because of the inductance change. So we would have to increase each element which is called “Boom Correction”.
There is a formula to calculate the “Boom Correction”. In fact, there are many different formulas to calculate the correction so I am going to use the one that I see most on the internet
C= (12.597B) – (114.5B^2)
The C equals the correction, and B equals boom diameter in wavelengths. This formula will work on boom diameters smaller than .055 wavelengths (Smaller than 4-1/2″ boom diameter on VHF and smaller than 1.5″ boom diameter on UHF). So let’s dissect this problem to make it easier.
To find B we’re going to need the wavelength of the frequency (146Mhz) that were going to use in millimeters.
300/146 = 2.0547 meters or 2054.7 millimeters.
Now we need to take the boom diameter in mm (1.0″ = 25.4mm) and divide it by the wavelength (in MM) of 146Mhz
25.4/2054.7 =0 .012362 (B is .012362)
Now we can do the problem
Now we take the correction and multiply it by the boom diameter (in MM)
.138226X25.4 = 3.510mm or .138″ is out correction
We now have to ADD .138″ to EACH element. So our NEW element lengths (in inches) are as follows.
RL = 40.633″
DE = 38.501″
D1 = 36.301″
D2 = 36.224″
D3 = 34.212″
At this point we should have all the lengths of the elements, spacing distances from the reflector to each element, boom diameter, boom length and the type of material we’re going to need for fabrication… Right?
We need to go shopping before we build. Here is a list of what we need to build
- 5ft (60″) of 1X1″ Sq Aluminum tubing (1/16″ Wall/Thick)
- 16ft (192″) of 3/8″ Round Aluminum Rod
I would suggest that you google for a local “metal supply” shop. I would avoid the big chain stores (like Home Depot, Lowes) or stores that have every type building material under one roof because the markup on material is very high. I was able to purchase 12ft of sq tubing and 24ft (2 12ft lengths) of rod for around US $30. There was enough material to build this antenna and two UHF 3 Element beams.
- 8pcs – 3/8″ Inside Diameter Plastic Shoulder Washer
- 6pcs – 3/16″ Inside Diameter Plastic Shoulder Washer
- 1pcs – 3/8″ Inside Diameter X 3/4″ Diameter X 1-1/2″ Long Plastic Spacer
These Items will be a little tricky to get. If you’re in the US, you can go online and order from a company called McMaster Carr. I have the part numbers listed on the blue prints that I’ve used. However when I put the antenna through the ringer (tests), I will see if I have to change the part numbers to something else. I have been considering using plastic rivets instead of shoulder washers because I am afraid that the adhesive (epoxy) will not hold the plastic shoulder washers to the boom. If you get different washers or insulators, The dimensions will differ from what I have on my blue prints, so please change dimensions accordingly. If you do order through McMaster Carr, They will only sell the washers and spacer in packaged amounts. If I recall the small shoulder washer came in a pack of 100pcs, the larger shoulder washers came in a pack of 50pcs and the Spacers came in a pack of 10. It’s great because I ended up making a bunch of antennas w/o having to make an extra order.
- Glue or epoxy.
Anything that you know will bond plastic to metal and will survive the elements (rain, cold, ice, snow, heat, wind). Still a good idea to use even if your using plastic rivets.
- 6pcs – 9/16″ Long #8-32 Screws
I would suggest using stainless steel screw as it will survive in the elements longer
There are optional things that you buy like Sq caps for the boom and vinyl caps for the ends of the elements for water and safety protection.
There is some more paper work to do (Grrrrr). Now that we have all these neat numbers and material, We should at least have some kind of drawing to help us when it comes to actually cutting, drilling and tapping these parts. I assume that your building the antenna for one or two reasons which are that you either don’t have enough cash to purchase a commercially made (and tunable) Yagi, or that you actually want to learn how these types of antennas work. So let’s take some more time to layout the antenna so we can have something to use when we’re cutting, drilling and tapping.
I am going to use software called “AutoDesk Inventor 2011″ which is a 3D design software that is used for CAD (Computer Aided Drafting) purposes. This software will let me make each part in 3D and assemble all the parts to make sure of proper fitment. This software will also let me create Blueprints based on the information I typed into the software. If you can’t get your hands on any type of this software, no worries. You can do the same thing on graph paper.
My Results are posted below. Please note that I’ve included all the information that is needed IN the Blueprint for those who just want to download the prints and fabricate w/o reading this article. However the information listed on the prints (other than the dimensions) have only basic information for experienced fabricators/ antenna builders.
**** INSERT BLUE PRINTS ****
(Still working on them, please check back)
Now that we have all the dimensions and a print, LETS GET FABRICATING!
Here is a list of basic tools that are needed. Most Hams have these tools or can get access to them. Following this list will be a list with the preferred tools that would make the job faster, smoother and more accurate. However the majority of people do not have a lot of the items
Basic Tools Suggested:
- Measuring Tape
- *Various Drill Bits (Ranging from .125″ to .750″)
- 8-32 Bottoming Tap (With T Handle)
- Bench Vise
- Sandpaper (120 grit)
- Scratch Awl/Scriber/Etching pen (or anything that has a sharp point that you can easily handle)
Preferred List Of Tools
- Metal Chop Saw (With vise)
- Vernier Calipers (6″ or bigger)
- Automatic Center Punch
- Drill Press (With a vice able to hold SQ and Round tubing/stock)
- *Drill Bits (Various to .750″ [or 3/4])
- Files or deburring device
* – For those who don’t have .750″ drill bit, depending on where you live, a 3/4″ Drill bit can get expensive. I would suggest either a step bit (still expensive) or a 3/4″ countersink (at 82 degrees). Drill the specified hole up to the biggest bit and then finish it off with the 3/4″ countersink. Since it’s aluminum, it will not damage the countersink and you will be able to counter sinks holes on other projects (DO NOT COUNTERSINK HOLES ON THIS PROJECT!
Lets start off by cutting all the aluminum rods (elements) and tubing (boom) to the correct lengths by using the tape measure. The blueprint posted in this article shows both decimal and fraction to the nearest 32nd of an inch.
After you cut the elements and boom to length, It’s time to layout the hole pattern on the boom and each element
I used a red pencil to mark the location along the boom. Then I marked the center of each location using a pair of verniers and used a marker to make the center point more visible.
When marking the elements it’s a good idea to mark the center point twice. Once from each end so you know that your exactly on center of the element. With the driven elements, you just need to place a mark at 3/16″ in from only one edge.
Using a drill or drill press with a small (>.125″) drill bit. Drill pilot holes on every center mark on the boom. DO NOT DRILL THROUGH THE BOOM! Only drill through the side you marked unless your using a bridge port mill that has a perfect 90 degree head.
Also drill pilot holes at the marks of each element. Once again, DO NOT DRILL THROUGH THE ELEMENT! You will only want to drill half way through the element. A bit of advice is to measure from the tip of the drill bit 1/4″ up and use the edge of some masking tape to tell you where to stop when drilling. If you feel un-easy about drilling the element, you should have a couple of inches of scrap rod that you can test both drilling and tapping on.
This photo shows pilot hole being drilled into the boom
After drilling the pilot holes, time to open the holes according the blue print. With the elements, I suggest using a .120″ (or #31) drill bit as the element could wobble causing the hole to open up a little more. With the boom I would start with opening the holes where the elements slide through first! Then switch to the 3/4″ bit and open up the holes where the driven element slides through. Switch back to the pilot drill bit, insert the plastic spacer that will hold the driven elements and using the two holes on the top of the boom as guides and drill halfway through the plastic spacer. Then open the rest of the holes to the correct size.
The next step is to tap each element with a #8-32 bottoming tap. If you can get your hands on a bottoming tap, you can take a regular tap and break the head off it and grind/file it flat.
After everything is cut and drilled and tapped to size. It’s time for assembly. Assembly is pretty stright foward.
Glue/Epoxy all shoulder washers/rivets into place and let dry. The driven elements are going to slide into the plastic round spacer. Make sure that each side of the driven elements does not come in contact with each other. Then slide in the reflector and directors and secure them with the 6-32 screws. When finished I placed more epoxy around the elements (NOT THE DRIVEN ELEMENT) at the point where they meet the boom. I did this because I don’t plan on taking apart the antenna.
Attache your coax to the driven element making sure you don’t have the connections contacting the boom.
You should hopefully have a functional 5el VHF Yagi
Here are some reading I’ve taken with a analyzer that I borrowed.
At 144.42Mhz, I got a 1:1 SWR with an Impedance of 48ohm.
At 146.02Mhz, I got a reading of 1:1 SWR with an impedance of 46ohms
At 147.72Mhz, I got a SWR of 1:1 and an impedance of 44Ohms
These readings were taken in my house with the antenna mounted to a wood broom stick. When I got the antenna into the attic I took another set of readings before I gave the meter back and I saw that a slight change on the values. Can’t wait to get it outside.
If you plan on making your own Yagi, please take ALL SAFETY considerations into effect. Know and respect all the tools you are using and when it comes to installing your Yagi, make sure the antenna with not come in contact with any utility lines.
If you are using the plans from this page, please note that your results may/will vary from what I’ve made. Since I’m new to antenna making, I would not want you to risk any material/money. Please confirm your findings with someone who does know before purchasing or building. These are just my notes on what I did to create an antenna.
Sources Of Information:
Peter P. Viezbicke, National Bureau Of Standards. “Yagi Antenna Design”. U.S Department of Commerce/NBS Tech Note 688 (Dec 1976). PDF (Sept 2011)
G.R Jessob, and R.S. Hewes. “Radio Data Reference Book” (ISBN: 1872309305) Radio Society of Great Britain; 6th edition (November 1995)
Unknown Author (N4UJW?). “Basic Yagi Antenna Design For The Experimenter”. YAGI ANTENNA DESIGN BASICS. Web (Sept 2011)
Martin Steyer (DK7ZB). “DK7ZB Yagi – 144Mhz-Yagis”. DK7ZB Website. Web (Sept 2011)
ARRL, R. Deam Straw. “The ARRL Antenna Book: The Ultimate Reference for Amateur Radio Antennas, Transmission Lines And Propagation.” American Radio Relay Leauge; 21st edition (May 2007)
Peter Knott. “Wire Antenna Modelling with NEC-2″. Antenna Engineer 8/12/2009. PDF (Sept 2011)
Daniel C Lester (KE9SE). “The Effects Of A Conductive Boom On Element Lengths”. VHF-UHF Basics (9/17/2009). Web (Sept 2011)
Guy Fletcher (VK2KU). “Effects of Boom and Element Diameters on Yagi Element Lengths at 144, 432 and1296 MHz”. ARRL QEX Magazine (Jan/Feb 2000).
Arie Voors . “4NEC2″ – Web – (Freeware) Program Used to Design and Simulate Yagi (and other) antennas
Autodesk Corp. “Autodesk Inventor 2011″ – Web – (Trial/Edu/Paid) Program used to Design and create blueprints
I’ve come to talk with you again.
APRS – ™ By: Bob Bruninga, WB4APR Http://www.aprs.org
Back in 2001 when I first got my license. I was interested in APRS because it was something I can do with my new license. I went as far as setting up a part time digipeater and after only a couple of months, the digipeater went down and lost interest in APRS because the cost of a GPS receiver at the time (even though GPS is NOT a requirement to listen or participate on the APRS network).
GPS receivers are a lot cheaper compared to 10 years ago and I have a old Garmin GPS-V lying around. So I figured this would be the perfect time to get back into APRS. For those who don’t know what APRS is, It’s Automatic Packet Reporting System which is an Amateur (Ham) based system for real-time communications of information using a digital protocal (AX.25). There are many possible things you can do with APRS. You can send (Short) text E-mail, SMS Messages, send weather data (Which the NWS uses) and when hooked up to a GPS , will send position data. I am not going to go into much detail because there are websites that are dedicated to APRS.
I am going to be doing a couple of things with APRS. One thing is that I am going to set up a part-time iGate (internet gateway) to make use of the frequency scanner and antenna that is not being used. Packets of Information received from the scanner (tuned to 144.39mhz) will be sent over the internet using the APRS-IS network so it can be databased and displayed on such websites as aprs.fi .
The other thing I want to do is location tracking. In order to do tracking you’ll need 2 or 3 things. You’ll need a GPS receiver that has an output for NMEA data, TNC (Terminal Node Connector) and a transceiver (VHF [144-148mhz] is Most used). As stated earlier, I have a Garmin GPS-V lying around and I also have a Kenwood TH-78A. All that is missing is a packet TNC. A Real TNC can cost $100+ and needs a computer. However there are units designed and built for APRS that will encode the data from the GPS to the AX.25 protocol and transmit the signal using the transceiver. I’ve purchased one of these units called ” TinyTrack3+” from a company called Byonics. It’s as basic as it gets. You can either buy it as a kit or assembled, with or without a GPS Receiver, with or without cables for your transciver or with or without cables for various GPS models. I ended up going with a solder and assemble your self kit without any extra cables because I wanted to invest the least amount of money in it as possible.
Here is the kit as you would get it in the mail. It comes with the componets, board, case and instructions.
Here is the board soldered up. I used a 35W Pencil type soldering Iron. I filed the tip a little bit to assure that solder flows to the tip. It took about 1/2 to 3/4 of an hour to solder. If your new to assembling boards, I would go to the Byonics website and download the manual because the online .pdf manual will cover the assembly and everything else in great detail. As long as you follow the step by step instructions, it will turn out great. For newbies make sure the diodes are going in the right direction, LEDs in the right direction and make sure the notch (little cutout) is aligned with the silk screen image.
Now that board is done, time to make some cables! (Since I didn’t order any)
Here is the cable all assembled! It’s a DB-9 Connector (Radio shack P/n: 276-1538 US$2.69) , Pos and Neg power cords with Anderson power poles attached so it could powered by many different sources (7-35vDC), Sacrificed speaker microphone from the Wouxun for its cable, Ferrite Core choke (Optional, Radio Shack P/N: 273-105) and the DB-9 Case (Radio Shack P/n: 276-1539 US$2.09). I Got the wiring diagram from the Byonics website and took about 1/2 hour to make which ended up costing me around $5 since I already had the cable, choke and power connector
Just an FYI, I sacrificed a speaker microphone from my Wouxun. Power-Werx which distributes Wouxun products (as well as the power poles), has the exact same cable for this application for sale on their website. They also have a similar one but with a cigarette lighter plug (Both for US$20). Byonics also sells cables for this and many different radios. Also note that that wouxun speaker mic layout is the same for kenwood HT’s!
After you assemble the tracker and the cable. Apply power to unit and hopefully it comes to life by flashing the yellow and green LEDS three times. Only thing left to do is to program the tracker using your computer. This point it can get tricky. The TinyTrak3 needs a NULL modem cable (Or adapter) to program it and possibly a gender changer. I found that I didn’t have a null modem cable, all I have are straight through cables. Since I didn’t want to wait for an adapter I made one from old computer parts lying around my house
Here is the cable that I made from parts out of an old 486 that I had in the attic. It’s not pretty or rugged enough for daily use but once you program the Tracker and are satisfied with the operation then you will most likely not have to program it again.
Here is the complete setup. Right now I have the unit running off a 9V battery. I also used a cigarette lighter plug with power poles connected to it. Depending on how you programmed the tracker, It will only send when there is data from GPS. There are limitless things you can do with this setup. For SOTA members (Summits On The Air), They can bring this along with them so others can see their progress in their hike. If you helping out in a public service or public events which ham radio operators are helping, you can show your location to HQ without even telling them. It makes things a lot easier.
Here is my first track. I learned a lot when doing this. I found that my handheld in the truck has a hard time communicating with the digipeaters in the area. I might purchase a small 1/4″ wave mag-mount or a duplexer and switch to my dual band antenna for when I am running APRS in the truck.
I added things to the Tinytrak3+ which I think will make it better for me to run. If I had to be really critical about the tracker is that the DB-9 connectors did not come with mounting screws. The first test out with my truck the power/radio connector became loose and eventually lost power to the tracker. To fix this I went scavenging parts off a old computer.
Now I can secure both the power and GPS connections. The screws came off the LPT and monitor ports of an old mother board. There is a small amount of space between the back plate of the connector and the board. So I had to grind down the bolts and nuts so It would not touch the board.
Another issue that might come is when I am portable (walking). More likely the power source for the tracker for this purpose will be a 9V battery. The tracker with all the LEDS running will consume around 18.6ma which means a 9V battery (.370Ah avg) could possibly last for about 9-12 hours (60% discharged). If you turn off the LEDs, the power consumption is 6.6ma. On a 9V battery, the tracker could last around 30 hours. The TinyTrak3+ can run without the LEDS by cutting a lead (tells you how in the directions). If you using a high-capacity 9V (.580Ah)with no LEDs it could last for more than 50 hours so it might be beneficial to cut the lead and add a jumper. The down side is that you will not know the status of the Tinytrak.
So what I did is cut the lead on the board and installed a bridge (shown in the picture above with the blue jumper). When jumped the LEDs are operational.
Also pictured are 2 bridges installed (on the left side) for jumpers J5 (outside pair) and J6 (inside pair). If J5 is jumped it will switch to what was programed in the secondary tab in the program (Program 2) . This would work great for an event which required either a different call and/or different settings. After the event, you can switch back to the primary settings. If J6 is jumped it will send a signal to power on the transceiver. This would involve another board with a relay to put power into the transceiver or modifying the transceiver. I don’t plan on messing around with it any time soon but since I am soldering on jumper bridges, why not.
Overall it was a really great build and I am having a blast with APRS. My plans are to find a way to make it all fit into a nice tiny package that I could carry when hiking or driving.
73 and thanks for reading!
This year I participated in Field Day with the Hampden County Radio Association. Instead of dropping by a site and using their equipment, I decided to offer up my equipment for use as the “HF DIGITAL” station. Other than a couple of software issues, the Digital station was a success with over 170 contacts.
Here are the pictures I’ve taken from Field Day
Check out Hampden County Radio Association’s Website for information about Field Day.