📡 Build a HUGE DIY Helical Antenna for the 2m VHF Band!

[@overture4414]

Very smart kid for knowing everything about how antennas work!!

[@KE8UYV]

I've been inspired to build a 2 meter helical now!! Good job! 👍

[@KJ7NLL]

If we did it again we would use schedule 80 instead of schedule 40 PVC because it is thicker and we were having some bending problems. Also, pin the tube as straight as you can get it, and then fill it with spray foam and let it dry before drilling holes. This will keep it nice and rigid. Depending on how long it is, you may still need guy lines to support it.

[@KJ7NLL]

Most of the helical antennas that we have researched are right hand circularly polarized.

[@JulietNovember9]

This is so awesome! It's so wonderful to inspire curiosity and critical thinking in a fun way with our kids. Going to have these great memories of hanging out with dad and building cool things!

[@OtherPerson101]

As a teenager myself, I find it amazing this kid has the proper tools and resources to build such antennas. While I've build my own share of crazy contraptions (including a cardboard satellite dish), they were all crudely built with stuff I scavenged around the house. Congrats on actually having the right tools for the right jobs!

[@jerryfat7498]

helicals are childs play, this kid is sharp lol

[@OtherPerson101]

It's probably more feasable to build a cross-dipole yagi "arrow" antenna at 2 meters though. That will still have the circular polarization while also being much quicker and easier to build while also giving higher gain.

[@deillos1lee]

could you please put the dimensions/blueprint in the description or so?

[@KJ7NLL]

Updated the description, let me know if you want to know more!

[@victoryfirst2878]

I am wondering if this antenna could be made to receive deep fringe VHF-UHF TV signal ?? The Free To The Air TV frequency ??? Nice work young lady too. vf

[@KJ7NLL]

It probably could, but the impedance match would have to be re-tuned.

[@victoryfirst2878]

@@KJ7NLL Any ideas on what type antenna would work best ?

[@SlawekKlimek55]

Great project!

[@luckydubeinrc5165]

curious about your feed point, how far away from center was the mount ? i built a 5 turn and it works great, feed point is 140 ohm, used an old dish 1.2m D and is still worked, pity we all have to have the turns in the same direction... to work each other, but thats how it works.

[@KJ7NLL]

I'm not sure what you mean by how far it is from center, but I can explain what we did: The reflector is flat with a 2 meter diameter. We mounted a BNC connector on the reflector of center at the same radius as the winding. The helix runs all the way to the reflector so, there is very little distance between the BNC and the first winding. I don't know what the raw impedance was, but we matched it using copper foil tape that extends along the first 6 inches along the helix that extends toward the reflector. We found that the edge of the tape needs to be very close to the reflector and we tuned it to 50 ohms by extending or shrinking the length of the copper tape.