Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

Ham Radio Multiband Ground Plane Antenna

by ok1cdj Jan 11, 2017
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Thanks for posting your remix. Do you find that the placement of the taps are accurate to what the original design video suggests? For example, 40 meter band has the top tap at 3 coils from the top and the bottom tap is 2 coils from the bottom? For some reason I cannot get my coil to produce under 2.3:1swr on 40 meter and the top tap is 9 from the top on 40m. My radiator and radial wire lengths are exactly as described. I originally made one with just the automotive wire loom with a slightly smaller coil diameter and am able to get 1.4:1 swr on 40 meter. My only thought is that I used too large of wire gauge (14awg) and the coils are too close together on the 3d printed structure with that wire size. Any suggestions? Thanks!


Have you had any success? I am trying to tune mine up since the "tundra" has subsided outside. Would like any suggestions if you had any.


I don't really have any suggestions other than get yourself an antenna analyzer. I spent many hours trying to get the taps in the right spot. As a result, I made one of my first HF contacts with this antenna. I no longer use it though. Good luck!


That is exactly what I was trying to do. I set the antenna analyzer to the 40 m band and kept trying to move taps to get the SWR to move. Then I disconnected all taps and found it was resonant about 15.7mhz. at least I have a starting spot.

Why do you not use it anymore?

Thanks for getting back to me!

The feed poins must be about 0.5m high abouve ground. Do not set antenna analyzer to 40m ! If you wold like to tune to 40m start with larger sweep. For example 5-13 MHz and connect radiating element to end of coil and feed to aprox 2-3 turns from bottom. Try to find resonance. If you will see resonance try to move taps to desired freq and matched impedance. With antenna analyzer you can tune antenna in few minutes...

73 Ondra OK1CDJ

This is very nice! I am curious what lengths of wire you chose to use for the radials and vertical? Really awsome!

Any chance of a remix to go to 10M?

For 10M band you don't need any coil. 5m radiant vertical element, a few 5m groundplane radials... ?

yes... you need tune elements by lenght to good SWR...

:) true, my ideia was simply that if the pole is 6m tall, one does not need coils for 10m, since half wave antenna would only need +/- 5 metres radiator. Of course, one should calculate the correct lenght, for the desired centre frequency.

How do i wire this up?

Wiring diagram added to pictures.

73 !

thank you very much, hopefully in a week or two i can throw up a completed picture. my printer is just a tad to short to print this fully so i'll have to shorten it up by 10mm or so to get it to fit. I see you have the scad files uploaded though so that shouldnt be an issue.
Of course i realize this after im 8 hours into the print.