This weeks website of the week is HomingIn.com
If you are into Fox hunting or RDF (Radio Direction Finding) then HomingIn.com is a must visit website as it’s full of information. Even though the website appears to have been last updated in 1998, it’s updated often and I would say that it’s the “Go to” site for anything RDF.
A new website to learn and practice Morse telegraphy has been launched:
http://lcwo.net/ - Learn CW Online
There are already hundreds of training programs, MP3/CD courses and practice
aids available, but LCWO follows a radically different concept: While sticking
to well-proven methods for learning and practice, all you need for using LCWO
is a web browser!
This gives the user the liberty to practice CW wherever an internet connection
is available, always retaining the personal settings, scores and statistics.
Currently the site, which is available in 27 languages offers a complete
Koch method Morse course, code group practice, callsign- and plain text training
modes and also allows to convert random text to Morse MP3s.
A high score list is available to compare results with other users, personal
statistics help to track training progress.
LCWO.net is a non-commercial project. Creating a free account only takes a few
seconds, and you can start practicing CW right away!
Fabian Kurz, DJ1YFK
It has a decent layout and after making an account, it will track your progress. I’ve used this site many times. My favorite part being the Morse Machine which is the same as this piece of software
Now maybe I should learn Morse Code…. Some day!
I have been seeing a lot of preppers out there on the internet promoting Amateur Radio. For those who don’t know what a prepper is, you can compare it to a survivalist as they are similar in some ways. In my opinion a Survivalist learns how to live off the land and a Prepper is “Preparing” for an event. It can range from someone preparing for a storm all the way to someone preparing for when the S#!T hits the fan ( SHTF as they call it) or “Doomsday”, the end of the world. Some of them go far as building huge underground bunkers equipped with enough fresh water, food, power and ammunition to last for years. Recent TV shows like “Doomsday Preppers” have increased the spotlight on these types of people.
I think some of these extreme preppers are nutty but as long as they are spending their own money and don’t bother anyone else, they can prepare all the want. Who knows, they might have the last laugh but I am not going to spend my life worrying about a “What If”. By the way, I do believe that you should have at least some preparations such as a flashlight, weather radio and the plans that are mentioned on the Ready.Gov’s website. I am not here to put down the preppers.
At some point along the way in the prepper movement, it was mentioned that Amateur Radio is a necessity as it allows you to communicate with the “Outside World” and to keep tabs on what’s going on. It’s suggested on many websites and there are a lot of YouTube “Prepper” videos which promote Amateur Radio. I am all for promoting Amateur Radio but the way it’s being promoted is what bothers me. Instead of focusing on Amateur Radio as a whole, it’s only focusing on the prepper aspect of it with a sprinkle of EmComm. I know it’s their angle but there is more to Amateur Radio than just for using it during an emergency or when “Doomsday” happens and I wish more of these sites would mention it or dive into Amateur Radio a little deeper.
Preppers getting licensed at what cost?
I am glad they are getting licensed and I am sure certain radio organizations are glad so they boast about higher numbers, but at what costs? Sure, they have a license but are they going to use the radio other than listening? Are they going to take advantage of their new license? Are they going to be interested in the hobby other than from a prepper standpoint? I would rather see 10 people licensed that are active and really care about the hobby than 100 people get licensed to check into a couple nets and put their radio into storage mode.
I am NOT stating that Preppers shouldn’t get licensed!
I am glad they are taking the steps in being legal. It’s better than having the equipment in the hands of someone who has no clue what they are doing or don’t care. Hopefully while in the process of studying for their license that they see what Amateur Radio is all about and end up being more involved. All I ask is for these websites/bloggers/podcasters/youtubers that are promoting prepping and amateur radio to consult an active and established amateur radio operator. You wouldn’t want me on your show giving prepping advice just because I’ve read a couple blog sites. There are many operators that would love to make an appearance to correctly promote ham radio. all you would have to do is just ask.
This is just my opinion, I maybe wrong!
Thanks for reading and 73,
Jeff – NT1K
That’s right folks, I went to NEARfest. No, not the progressive rock festival but the New England Amateur Radio festival held every spring and fall in Deerfield NH. It’s considered to be New England’s largest and most attended hamfest. If you’re an amateur radio operator in the Northeast then there is no way you never heard about it. Due to other things going on in my life, it was either play in the New England QSO party (NEQP) or NEARfest. I can’t do both so I went to NEARfest but for only Friday.
Even though it’s not true, I’ll just say I’ve never been to NEARfest. I’ve been to Hosstraders which was the name of the hamfest before but I was very young and didn’t really pay attention to anything that was going on.
I left early Friday morning in hopes of getting there early. Further east I got, the more traffic started building up for those who are commuting to the Boston area. I got to the Fairground around 8:00 with a line of 20 or so cars of those who didn’t have tickets to “Get In” the fairgrounds. As the gates opened I was impressed in how fast people and cars were herded into the fair grounds. I was expecting a long wait because I assumed they were going to “inspect” everyone’s tickets. They did a great thing and sold tickets to every car in the waiting line.
Upon entering and parking, I wanted to shop right away to scoop up any deals before anyone else did. However I found out that most of the tailgating vendors were in the line with me and still had to setup. So the walk around the fairgrounds was to get a layout of the land. As more tailgaters and vendors were lining up I went around again and started purchasing stuff
My Shopping List
- 250pf Variable Capacitor (Antenna Project)
- Toroids – Various sizes and types (Antennas / RFI projects)
- MCX to SMA connector (RTL-SDR)
- Soldering Station (Grounded Variable Temp)
- Various RF connectors
- RG-213 cable
What I ended up purchasing:
- Rigrunner - Well within my price range
- MH-31 Handheld Dynamic Mic ( For my FT-736R)
- 250pf Cap (not the butterfly type like I was hoping)
- Toroids – Two tailgaters were selling various toroids. Wasn’t sure of value but purchased anyway
- Various sizes and values of variable caps – They were cheap enough
- MCX to SMA cable
- Battery for my Motorola XTS3000
- RG214 cable
So I purchased some stuff that was not on my list. Who doesn’t
To be honest I didn’t know what to expect when I showed up. For the most part everyone was friendly and you can see the “cliques” forming. All the military stuff was in one area, all the whackers had their light shows parked next to each other and it appeared that it was more of a social gathering of hams than a “Flea Market”. I was expecting NEARfest to be similar to the Swap/Sale section of the QRZ forums with everything marked up because it’s “Vintage”, “Rare” or “Barley Used” but I was glad to see that most of the tailgaters and vendors had decent prices with a sprinkle of those who think their equipment should go for as it were new.
When it comes to anything amateur radio related, I expected the smelly ham, the mega obese ham, the scooter ham, the mega nerd and the high visibility whacker ham. What is a Ham Fest without them. I was expected to see them, I did and I am used to that. However this year I saw quite a few “Boston Marathon” hams to point where I could have made a drinking game for every one I saw. I guess by wearing the neon yellow (or blue) jacket you’re telling everyone in eyesight that ”I was there man”. I am not sure of a reason to wear that jacket other than at the Boston Marathon or to show off that you were at a tragic event. I’m still not clear as to why someone would constantly wear it. Haven’t notice people wearing previous years jackets like what I saw this weekend.
On another note, I got to meet and have a very small chat with Burt Fisher (K1OIK), who is a known in the Amateur Radio world for his youtube videos, some of which are very controversial. Some might find him to be offensive, a trouble maker and demeaning to amateur radio but I really don’t think so. I may not agree with everything he says but he is just a person with an opinion. With differences aside, He has a lot of very informative videos so I give him credit.
I would have to say that I had good time. However I wouldn’t return unless I had a reason to go that would make the effort worth it. I could have purchased all the stuff that I got from the fest online for similar prices including shipping. If I had a bunch of stuff to sell or was looking to purchase a big ticket item such as a transceiver, amplifier or antenna rotor then I can see it worth returning. If you’re active in amateur radio in the Northeast, then I would at least go once.
Thanks for reading,
Jeff – NT1K
One of the things that attracted me to Amateur Radio is the community of people who are eager to help. If you’re having trouble with the exam, wanting to design and/or install an antenna, repairing a radio, purchasing the correct radio, working a kit or project or whatever it may be and you need help, all you have to do is ask and most of the time someone is willing to help. With the advancement of the internet and the use of forums and social media, it’s eaiser than ever to get the help you need from someone who has the correct answers.
For my first WOTW (Website Of The Week… Yeah, I’m calling it that) is KB6NU’s blog. I like his site because it’s current and frequently updated both in design and content. However the main attraction of his website is his “No-Nonsense Study Guides” to obtain or upgrade an amateur radio license in the USA. These guides gives you the questions and answers that are on the test with a brief explanation in way that makes it easy to understand. This allows the reader to get a general idea of what the questions are about w/o having to read pages and pages. It’s more than just memorizing questions.
I’ll be honest and say that I’ve learned more about amateur radio after obtaining my license because I wanted to, not because I have to. License manuals from the ARRL are filled with all the information you could possibly need to get your license (or upgrade) but for someone who is brand new to the hobby, it can be overwhelming with all this information being thrown at you at once. Some might argue that this information is necessary to know before obtaining a license and I somewhat agree. I wouldn’t want to see an operator cause interference, damage property or injure themselves or others but I don’t think they will be building a legal limit amplifier and erecting a 100′ tower right from the start.
Personal opinions aside, the questions in the exam are in there for one reason or another. KB6NU’s guides makes it easier to learn and I wish used them while I was obtaining my licenses. KB6NU’s guides are public (in PDF format) and I strongly suggest that if you find them useful that you donate through his website
Thanks for reading,
- Jeff (NT1K)
Website of the Week. May 1st 2013: KB6NU’s Ham Radio Blog
After a year or so of trying, I finally got the ARRL’s WAS award. For those who don’t know, WAS stands for Worked All States. In order to get the award you have to prove that you talked to someone in every state in the US. You can prove it by either getting QSL cards and having them checked and/or using Logbook of the world (LoTW).
ARRL has an online QSL service that allows operators to upload their logbooks into a giant database. After the log is uploaded, the contacts are crossed checked against other uploaded logs from other operators. If a match is found then the contact is confirmed. Those confirmations can add up and be used for all sorts of awards that the ARRL and CQ.
Before LoTW you would have to use QSL cards that involving printing, sorting, labeling and mailing. Most people want a SASE (Seld Addressed Stamped Envelope) to be included with the card. For other countries, you could save some money by sending the card through the Bureau. With LoTW it makes the process much easier, After setting up an account and confirming it, you can sign and upload logs to LoTW. No cards, SASE, postage necessary.
I wish that all operators would use LoTW. Some choose not to use it for one reason or another. Some people that don’t use it give the excuse that it’s too hard to register and use. I wouldn’t tell you that it’s easy but it’s not that difficult if you follow directions on the ARRL website. It seems difficult because of the security involved in making sure that you ARE the operator uploading the log and that the log belongs to you. If it wasn’t secure then LoTW couldn’t be trusted so that is why I support what the ARRL is doing.
So if you don’t have an account and you use an electronic logging, I strongly suggest getting an account with LoTW
I have the Basic WAS award. It just means that I made contact with every state. It doesn’t matter how you did it. You can get multiple WAS awards for each band and mode. You can the triple play award by working each state using Morse code, Voice and Digital.
Hopefully I can get triple play by the end of the year.
The Quick Way!
You can get the WAS award by casual contact with operators but if you want to make things go faster, there is a couple things you can do to make getting the award a lot easier.
RBN (Reverse Beacon Network) – With SDR technology, computers are scanning the bands and looking for CW contacts. If someone is calling CQ, there is a good chance that an SDR receiver heard it and posted (spotted) your CQ on the internet for all to see. You can use RBN to find state and/or country you need.
Ham Spots – This website collects and indexes the “Spots” from all different networks. It allows you to pick and choose who to make contact with without having to search the bands
Those two services depending on operators “Spotting” other operators. Even though the CW contacts are automatic. The state or country you want to make contact with might now be on the air. You can schedule (sked) a contact with an operator from the state or country needed.
K3UK’s sked page – This is an online chatroom/forum that allows you to schedule contact with other ops in the room. You will both get on the air, make contact, log it and then return to the website to work more
Over the Air Nets – There are many nets on the air that are meant for chasing awards. You check in and wait your turn to make contact with another operator on the net and vise verse. One that comes to mind is the OMISS Net
Hope to catch you on the air. If you need Massachusetts for anything, you can contact me and I will set time aside to help you!
Thanks for reading,
I am going to try out posting my thoughts and opinions when it comes to Amateur Radio here on NT1K.com. Reason I’ve been holding back is that I consider myself to be nice guy… Well, most of the time. I do “bust chops” but I try to let people know that I’m not after them. Most times, I am just trying to help. I don’t want to be just another blogger complaining about things and cast myself in a negative light. When it comes to talking about any subject, I always try to keep an open mind and look at ALL sides of the topic. Everyone is different and I try to write for everyone but at times, it proves to be difficult. When it comes to Amateur Radio, there is always someone who is never happy and will find any excuse to make it known.
One of the big reasons why I created this website was to help people by either showing them how to do things in an easier way to understand. I often come across articles that either don’t give much information or the information is so complex that you’re left scratching your head. The original goal of this site was to make it easier for those who are just getting into the hobby to understand how to do things from scratch and why. I am still going to do that but at the same time I am going also going to tell you my thoughts and how I see amateur radio. So if you can withstand my horrible grammar and spelling, please take your time to read what I have to say. Who knows, you might enjoy it!
Thanks for reading,
Jeff – NT1K
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)
Now that my station has grown, I have quite a bit of equipment that requires 12-14Vdc of power. In the past couple of years I decided to start using Anderson Power Poles. I decided to use them as it’s starting to be the standard of some organizations and It’s easy. My only complaint that I would have is that sometimes the connectors can loosen up and doesn’t require much force for them to come apart.
At this point I have a very minimal setup that needs to be expanded. I have a pigtail off the power supply and set of power poles on each device. If I wanted to use one device, I would have to disconnect power from one device and put it on another.
The obvious solution to my problem is the use a distribution panel. There are some commercially made panels that use Anderson power poles but being the cheap ham that I am, I figured I can find a cheaper way.
While at a local hamfest this past weekend, One of the vendors had a bunch of products that use the Anderson Power pole. Two of those products has caught my interest. One of the was the “EZ-Gate” by ham source and the other was distribution block by Quiksilver. The EZ-Gate is similar to the PWR-Gate by West Mountain Radio but doesn’t have LEDs or Fuses. The EZ-gate is half the cost of the PWR gate and this would allow my station to instantly switch to battery backup during events like field day or when the power goes out in my house. The power distribution block was just a simple 4-way connection using power poles and priced at $20. I thought the price was fair but I thought would be cheaper and fun to make my own at home, For the price of one block, I decided to get twenty pairs of power pole connectors.
Having no clue how the little distribution blocks were made, I thought of way that I think it was done with the commercially available ones. I used 12ga soild copper wire to connect everything together.
Here is a photo of what I started with and the final product.
I cut 4 wires about 1.5″ long and placed the connectors on each end and did a quick assembly to check the gap between the sets. I wanted the gap to be short as possible so the entire block would remain rigid. I also cut and bent two additional wires to act as a “link” to the top and bottom sets.
Here is one of the wires that I crimped the ends on. After crimping I soldered each end to make sure of a good connection. Please note that the connectors on each wire are opposite angles from the other side. At this point I installed the wire and marked the location where the link will go with a sharpie.
Two of the four wires, I soldered one “link” favoring one side of the wire.
Here it is halfway assembled. you will notice the link on the positive side very close to the connector. When the other side will be installed, the other link will be close to the negative block on the opposite side.
Before connecting the other side, I used a pair of pliers and curved the links around the top stack of the link.
After completely soldering the links and installing the other end, I wrapped the positive side in plastic. If I were to do this again, I would solder, install heat shrink tubing both leads and then install the other set of connectors.
For what I would have paid for ONE commercially produced block, I’ve made two blocks and had and also have an extra set to make a patch cable or pigtails/adapters.
It’s no rig runner but it works and does what I need it to do.
Thanks for reading!