LionHeart Sends – Yardstick Yagi

Hello Happy Partisans,
UHF is a major part of the comms effort around here and I put in extra work to keep that part of our game improving. This weekend I decided to build a Yagi antenna using material within ten feet of where I was standing in my kitchen when the idea struck me. A closet produced an old wooden yard stick and a handful of flimsy metal shirt hangers. The junk drawer offered rubber bands, side cutting pliers, poorly sized crimp ring connectors and a calculator. I cheated with the split post BNC adapter, aka cobra head, since that was down the hall and more than ten feet away.
Half an hour later I was up and running. As you can see in the photo Yagi math allowed me a six element unit using what I had. I built it for 460 Mhz and 462 gave me an SWR of 1.08. Dropping to 442 moved the SWR to 1.27.
Dimensions for those who care are 12 inches for the driven element, cut evenly in half with rings crimped on the end. I filed off some hanger enamel before crimping for a better connection. I also cut down and reshaped the ring connectors as they were too large for the posts. 12.75 inches for the reflector and 11.5 inches for each director element. Rubber bands hold each element in place. I read somewhere that antennas with 4 or more elements do better with .25 wavelength spacing instead of the usual .15. .15 gives a 10Db gain and .25 amps it to 27Db, but can’t prove that. Anyway .25 gave me 6.5 inches between elements and the SWR results are fine with me.
Feel the need to learn how to make this stuff and use it properly? I know somebody who offers a class for that. Your disaster plan will thank you.

Spread the love
                

Share This Story, Choose Your Platform!

About the Author: NC Scout

NC Scout is the nom de guerre of a former Infantry Scout and Sergeant in one of the Army’s best Reconnaissance Units. He has combat tours in both Iraq and Afghanistan. He teaches a series of courses focusing on small unit skills rarely if ever taught anywhere else in the prepping and survival field, including his RTO Course which focuses on small unit communications. In his free time he is an avid hunter, bushcrafter, writer, long range shooter, prepper, amateur radio operator and Libertarian activist. He can be contacted at [email protected] or via his blog at brushbeater.wordpress.com .

13 Comments

  1. BelieverPatriot March 19, 2021 at 06:31

    Nice! Don’t forget to add a gama match to fix that wicked impedence mismatch (probably 20 ohms or less). A piece of coax will do the trick.

  2. BelieverPatriot March 19, 2021 at 07:11

    Nice! Don’t forget to fix that wicked impedence mismatch with a gamma match or piece of wire like this: https://www.changpuak.ch/electronics/HB9CV.php

  3. Anonymous March 19, 2021 at 08:10

    5

  4. Anonymous March 19, 2021 at 10:18

    0.5

  5. Johnny Paratrooper March 19, 2021 at 10:24

    Nice. That’s pretty awesome. And it’s cool because you could, in theory, adjust it a hair at a time and be extremely accurate(For obvious reasons) with your spacing.
    This is going to be my first Yagi. I’m about to buy a case of yard sticks.

    • NC Scout March 19, 2021 at 10:26

      Welcome to the addiction.

      • Johnny Paratrooper March 19, 2021 at 10:40

        Radios are cooler than firearms. Firearms are cool, no doubt, but playing radio is far more complex and intriguing.

        • rto-jerry March 19, 2021 at 22:45

          Agreed JP! Only to have an FO and FAC to comms the fire breathing hell communist deserve! We shall settle for comms to fellow MAG’s within an AO.We all be the lone bone cavalry!!

  6. kc March 19, 2021 at 20:29

    WHAT impedance mismatch?? Those VSWR numbers are just amazing for a quick-cut antenna. THANK YOU for taking the time to share this. Superbly done Lionheart!

  7. FlyBy March 19, 2021 at 20:58

    Very nice. I’ve been wanting build a Yagi for a while now, but haven’t had a chance to purchase what I thought I’d need. I have all of this stuff sitting around the house. I’m going to flat out-right copy your build. Thanks for posting!!

  8. Cavguy March 20, 2021 at 10:20

    Here is an option often over looked, the Moxon. http://www.k6sgh.com/antennas/moxon.htm
    I have fashioned one for 2 meters with great results.
    But my focus lately is SOTA, with a KX2, QRP Guys No tune half wave end fed, suspension pole, and a Bioenno Power cell. Will activate W7I/CU-327 today.
    73,
    Cavguy
    Aka, Saber 7

    • BelieverPatriot March 20, 2021 at 22:01

      Nice, Cavguy. I run the EXACT same setup with a 100 watt Elecraft amp and 25 AH LiFePo. Have often wondered why all us radioheads don’t occasionally do an HF field day to hone the long distance portable skills. Maybe we can talk NCS into calling for one.

  9. FDC March 23, 2021 at 01:41

    Fun project, but then get online and spend the money on an Arrow, Elk, Diamond, or HyGain.
    Also, when mounting this, keep in mind a couple things.
    1. When mounting your yagi, you are going to need to have the ability to mount it vertically to really push the FM limits. Horizontally mounted to Vertically polarized (Most FM HTs, mobiles, base stations) may get through but it’s going to be a huge dB loss (aka sound like trash). Horizontal is for SSB/CW and some amsat stuff, but unless you are coordinating talking to someone 2m ssb, around here at least, you’ll be talking to yourself seeking contacts.
    2. Your mounting hardware needs to be outside of the path of the directing, driven, and reflecting elements. So tripod legs, masts, mast mounting hardware, hands, excess coax, etc needs to be minimal or non-existent between those elements because it’s going to do wonky shit to your propagation and gain.

Comments are closed.

GUNS N GEAR

Categories

Archives

Spread the love