Building 80m Inverted V Antenna for Restricted Space: VU2XTO Design

Caution: VU2XTO has informed that high power with a linear amplifier should not be delivered to this loaded coil dipole as it can result in heating of coils.

 I can hardly squeeze in a 40m inverted V at my home. Still I wanted to try out 80m as some of my VU friends have started trying it out. I was told by an online DX friend that 80m is a very busy band in EU with DX even up to Middle East at night. I was active on 80m in 1980s with a horizontal dipole antenna tied on top of coconut trees at my parents' home using a homebrew 3 x 807 AM/CW radio. VU2XTO design published in the Madras Amateur Radio Society Newsletter, Volume 26, Issue 2, July-September 2018 has the details of an 80m antenna for restricted spaces. What we need is a couple of 118 microhenry loading coils and about 14 m of insulated copper wire.


For the 118 microhenry coils, VU2XTO has suggested a 15cm UPVC former of 1.5 inch diameter and 18 SWG enamelled copper wire wound closely for a span of 11cm. It is basically an upgrade of a 20m antenna. So you need two pieces of insulated copper wire of 5m each from the feed point to the loading coils on either side. Beyond the loading coils we need another 2m each of insulated copper wire to make the antenna tune for 80m also. It has been suggested that we should first tune the 20m part of the antenna for 1:1 SWR and then tune the extra 80m part. 

As I was not quite sure of how much enamelled copper wire I would need, I went and bought 500 gm of 18 SWG enamelled copper wire along with 15 m of 2.5 sq mm insulated copper wire, of which I will need 14m for the antenna. Remaining part may be kept as extra for tuning and tying the antenna, meant to be kept folded on either side. Now I have to cut pieces of PVC pipe which I have and wind the loading coils as well as cut the antenna, mount it and tune it. I would request my 40m ragchew friends to take it as a challenge and come up on the morning 80m net on 3.6 MHz at 7.15 am, at the earliest. Anyone with space for mounting a 40m antenna can easily mount this antenna for 80m, as the total length is less than that of the 40m antenna!

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