Sunday, 20 November 2011

Inverted delta loop for 80m (and other bands!)

Once again I climbed up my trees and installed an antenna. This time an inverted delta loop for 80m.
1:4 balun. As you see, all joints aren't weather sealed yet.
The antenna is not completely symmetrical, since I have to respect the positions of my trees :) The 'north'  corner of the antenna is 30m up and the 'south' corner is at about 12 meters. The feeding point is about 1,8 meters.

I started the project with a 82m cable. With pure luck, the initial SWR tests were good for 80m, so until I measure my antenna with a MiniVNA I let this be as it is.

The results then?
I hadn't checked the theory for delta loops, so I was surprised about the results: it shows SWR far less less than 2:1 for all HF bands, except 160m but including the WARC bands! After a few days of testing I have an antenna that can do QSOs on all those bands. Including some nice DX stuff: VE on 80m, KH6 and ST2 on 40m, JY on 30m, ZL on 20m, Z24 on 12m and LU on 10m. Yes, I am happy with this all-round antenna!

Later experiences (updated 26.Nov .2011):
This loop makes me hear a lot more on the bands than my band-specific dipoles and ground planes. The difference is like looking at the stars with or without binoculars!


  1. Also KL7JR loves his 80m "all band" loop, though it is horizontal:

  2. Hello Karhu, just dicovered your blog. For the last couple of years I set up a 84m horizontal quad loop on about 8m height. Very good for NVIS operation but on the higher bands suitable for DX. The only bands that it not peform well are 160m and 10m. I feed it with 450Ohm ladderline and use the 1:4 balun in my palstar tuner. 73, Bas

  3. Interesting! An 80m loop should not tune at all to 160m I think, so I think the loop is ok for 80m and up. I have had quite good experiences also on least compared to my 10m dipole. At least the loop listens much better than the dipole.

  4. Latest experiences: I obviously have some losses in the feeding line, since the loop tunes a little bit too well to all bands. Anyway I have worked some good DX e.g. on 30m and 17m with it. On 80m I have no problems hearing very distant stations, like Japan, but they cannot copy me. Obviously I need a vertical antenna for transmitting outside europe...however, the loop is excellent for listening.