UHF – NT1K – Welcome

Antenna Reviews: Arrow Satellite II Vs. Elk Log Periodic

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.

Pros:

Uses aluminum
Lightweight
Tuneable (Gamma Match)
Built in duplexor
Use either 144 or 440 or both.
Breaks down into a small area

Cons:

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.

Pros:

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

Cons:

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.

Dueling Antennas.

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!

73,
NT1K

My Offset Attenuator Project

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

Qty	Desc	Price	P/N	Source
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.

Final Assembly

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

Lessons Learned

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!

73,
Jeffrey Bail (NT1K)

RTL-SDR = CHEAP FUN

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.

Field Day Fever

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.

NT1K FD 2011 — NT1K Doing Digi (Photo By: Frandy Johnson, N1FJ)

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

Contesting… Huh?

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)

Homebrew GMRS 3 Element Yagi

Since I’ve built a ton of J-Poles and wire Antennas, I’ve wanted to build something different. I decided on a 3 element YAGI built for GMRS that is directly fed with 50ohm coax. After a couple of failed yagis and the help of another ham on QRZ.com forums, I finally built a Yagi that works! The reason I’ve chosen a Yagi built for GMRS is due to the ultra high frequency, which ends up being a small antenna. If I were to mess up (Which I did), the material cost would be low. I also wanted to use it on a GMRS repeater in the area.

The first Design I used is with a Web Site that has a Java base applet to design the Yagi, After getting all the Dimensions from the website, I went to work building the antenna. After everything was done, I learned two things. One is that my drill press does not drill straight (90 Degrees) through the tubing. The other thing is that when I hooked up the antenna to a simple SWR Meter, That didn’t work either (Pegged the Meter). At this point I got frustrated and posted my issue on QRZ.com. A Ham by the call of WB3BEL (Harry) took my dimensions (That I got from the applet) and plotted my antenna into 4NEC2 software (Like EZNEC but freeware) and it would not work for the center frequency of the GMRS Band (or any part of the GMRS band).
WB3BEL actually re-designed the antenna to where it would work so I give him credit and major thanks for help. I took his Dimensions, Modeled the antenna for fabrication and built the antenna. I Hooked up the antenna to a transceiver and SWR meter and got a 1.2:1 SWR and a 1.5:1 SWR on the outsides of the GMRS band. The Design is calculated to yield 7.5Dbi of Gain. Considering connector and cable loss (Lets say 4Dbi using 50ft RG-213 W/ 3 SO-259 Ends and a Barrel Connector) still yields gain of around 3.5Dbi which is not too bad.

Here is rendered Image of the Antenna. The elements are Insulated from the boom using plastic shoulder washers for the Reflector and director. The Driven Element is insulated using a 0.750(OD)X.375(ID)X1.5″(L) Plastic spacer. Since the elements are going THROUGH the boom, It will make the elements electrically shorter so you have to compensate for the loss by adding 0.279528″ (7.1mm) to the element to correct the effect (Boom correction). The elements are secured using #8-32 Screws screwed to the boom. The screws are also insulated from touching the boom. The screws do not make any significant changes to radiation pattern of the antenna as long as it’s insulated from (not touching) the boom. I did notice that the screws actually lowered the SWR a tad which is great.

I didn’t add a matching network to the antenna because I wanted an easy to build and assemble antenna which is the entire point of this article. The antenna is fed using RG-213 Coax with terminals soldered to the core and shield. I tried to keep everything as short as possible because this and the ring terminals effect the performance and SWR of the antenna.

Here are a couple of screen shots from the antenna software that show the Radiation Pattern and gain. Nothing special here.

Here is the calculated results for the SWR of this Yagi. Please note that it’s in the ball park. By adding screws, coax leads and the ring terminals, it could or will effect the final pattern and/or performance of the antenna.

Here is a SWR Shot. As you can see, I don’t have a very good meter. I would like to buy a HF/VHF/UHF Antenna analyzer for my Antenna builds but I don’t think that will happen in the near future.

Here is the complete Antenna.
Overall it was a fun little project. It took a short time to build and it’s a great directional antenna with some gain to help your signal on GMRS reach its destination.

Continue reading if you want to build this antenna.

Continue reading “Homebrew GMRS 3 Element Yagi”

FIELD DAY – 2 Weeks!

I will be participating in Field Day this year with the folks from the Hampden County Radio Assocation ( HCRA ). I’m excited because I will be using my FT-950 as the site’s HF Digital station (Mostly PSK, RTTY). So if you live or will be in the Western Mass area on the 25th and 26th of June and want to see Field Day up close, we’re going to be at Dufresne Recreation Area in Granby, Massachusetts. All are welcomed, licensed or not. Please visit the Field Day page on HCRA’s website. Also check out pictures and data from prior years

For those who don’t know about Field Day, It’s basically an event that takes place on the 4th weekend of June to test emergency communications and it’s deployment. Over 30,000 operators across US try to communicate with as many other field day operators as possible. Points are awarded to operators and/or clubs that make contacts and perform other tasks that would allow for more points ( For example: media coverage, getting Non Hams on the air [GOTA], Copying/fowarding messages). Some Hams treat this as contest even though the ARRL considers it an exercise. Whatever the case may be, it’s really fun and it can get you out of the house.

I’ve participated in Field Day multiple times at multiple hosts over the years. I’ve had a Digital setup back in 2004 and had a blast. I recall being very busy using digital back then, I hope that it’s even more popular this year compared to 2004 and hope to be more busy making contacts all over HF.

What: ARRL Field Day Hosted By the Hampden County Radios Association
When: Saturday, June 25th, at 14:00 (2pm), untill Sunday, June 26th
Where: Dufresne Recreation Area, Granby MA, 01033
Why: Because it’s fun, social and you get to operate all different type of equipment.

Hope to hear or see you at Field Day!!

I’ve gone Bat$#!t – Hello Moto(rola two-way)

In the past couple of weeks I picked up a couple commercial two-way radios. I’ve purchased a Motorola Maxtrac 300 (Mobile) and a XTS 3000 (Handheld).

I’ve been a fan of commercial radios since I got my hands on a HT1000 and beat it up pretty good. I’ve dropped it, thrown it, threw it into a puddle and who knows what else and they always worked out.

There are PROs and CONs about owning a commercial radio for Amateur use. One of the CONs is programing. Unlike amateur radios, the majority of commercial radios have to be programmed. With Motorola, depending on the situation, the software that is used to program these radios will end up costing as much as half (or more) of what you purchased the radio for. You could also have a local dealer program the radio. Another one of the CONs is the ability to change the frequency “On The Fly”. You can only change to a frequency (Channel) that is programmed into the radio.

One of the PROs are that you will get a radio that is built to public safety and/or military specifications. These radios can take a lot more abuse then it’s amateur counterpart. Another PRO is that these radios are built as “Part 90” (Public safety, Private business, municipal, etc) radios. That means you can use these radios in both the LMRS and Amateur frequency blocks. Your not allow to take a amateur radio and modify it to transmit in the LMRS. So if you have a job that uses radios in the LMRS blocks or you want a radio that can do both GMRS/UHF (Or MURS/VHF) then you will have a radio that will possibly cover all 3 possibilities.

This is the Maxtrac 300 I got on e-bay for around $100. It was being advertised as a 430-470mhz split which is rare but when I hooked it up to the computer, it was the 450-470mhz split.

Just a note for anyone that is looking to buy this or it’s GM300 brother on eBay. Make sure the auction has the Model number in it. For example, the model number D34MJA7JA5AK means that’s it’s a 10-25w (2nd Number[3]), UHF (3rd # [4]) Conventional (Numbers 4,5,6 and 7[MJA7]) 32 Channel (8th # [J]) A5 HEAD (9,10th #) Revision K (Last Digit).

So now you know your getting 10-25 watt 32 Channel UHF radio. However these types of radios have 2 splits per band. On Uhf you could get getting a 403-430 or 449-470 split. I’ve read that there is a 430-470 Split RF but I have yet to see it. The only ways to tell what split the radio is, by looking at the radio in the RSS (programing) software or actually opening up the radio to see what the part number is on the RF Board. So be careful if your looking for a Ham band Maxtrac.

This is my Motorola XTS 3000 UHF Handheld radio. I purchased this item because the “But It Now” price was just where I wanted it. Another reason is that it can decode/encode P25 Digital. Always wanted to mess around with it and now I have the chance. Only issue is that there is only two P25 systems for ham radio in the state of Massachusetts and they are both located out of range. If there is enough interest in the area, I would like to setup a repeater capable of P25. We’ll see…

Thanks for reading!

OSJ-Pole – Adjustable

The thing that amazes me about the Open Stub J-Pole is it’s simple design that performs well. I am not saying it will out-perform commercially built high-gain antennas but that it performs well using a few parts. I think it’s even easier than building a copper J-pole and even ground plane antennas (maybe just a step up).

One of the big complaints that I’ve been reading about the Open Stub J-Pole is that it’s difficult to tune. The only way to tune the antenna is to actually cut the stubs a little bit at a time. If you cut too much the stub is now worth it’s weight in scrap.

Now that I am the owner of a GMRS radio, I wanted to build a OSJ-Pole that you can adjust with ease. I found plans on the internet for a Copper Cactus J-Pole that used a brass screw threaded into the “Tuning element”, or the Short stub (By Glynn Rogers, K4ABT). I am using that idea on the OSJ-Pole. What I ended up doing is cutting about 3/8″ off the top of the short stub, drilling a hole down the center of the rod, tapped it with a 10-32 thread and inserting a screw with a jam nut. Now I can move the screw in and out to obtain the best SWR and then tightening the jam nut to secure the screw.

Here is a picture of what I am talking about

I tried to make a custom angle bracket with what I thought was the correct spacing but the SWR was horrible So I used a extra bracket from one of the many Dual Band OSJ-Poles I’ve built. It worked out pretty well.

Here is a close up of the tuning screw. I ended up using a lathe and a drill bit (.159) to put a 2″ hole at the end of the 3/8″ round short element. I then used a bottoming tap to make the 10-32 threads as far as I can go. I then used a 1-1/2″ Screw and a 10-32 Jam nut to lock the screw in place. I am sure this can be applied to any of the Open Stub J-poles that are out there. Just make sure to cut some material off the elements so you have room to adjust above and below the calculated line. For the dual band you’ll have two adjusters. Since most people don’t have lathe access to make the hole in the center of the 3/8″ rod. A vice, center punch (automatic or not) and a steady hand with a drill will do. I would make a pilot hole with the smallest drill bit in your stock (under #21 or .159″).

I was able to tune the AOSJ-Pole from a 1.5 to a 1.0. Since I am building more and more antennas, I saving my pennies to buy a antenna analyzer so I can give better reports with more information than what I am getting on my SWR meter.

Next project will be a GMRS 4 Element Yagi.