This antenna does not work well with a Balun. I have tried it and went back to the Q-Section. I have been using a 40m Horizontal loop for over 3 years now and simple is best. No balun, no ladder line, just (in the case of my original version) garden, fasten-up wire and 75 ohm satellite dish or normal TV coax, cut to the correct length for 40m based on its Velocity factor and then the standard Rg58AU or RG-213 50 ohm feed to the shack. Handles up to a KW no problems. After moving the antenna to Germany from Australia, the wire got upgraded to the light thin wire with teflon fibres in it for strength. Actually didn’t improve performance but it looks better as it doesn’t kink so easily.
The 40m full wavelength horizontal loop antenna at anything over 5m off the ground (ideally 7-10m) works well on 40m and even better on 20m. Without the Q-section, you won’t get the SWR down below 3:1. With the Q-section for me it’s between 1.5:1 and 2:1. Karl has managed to get his even better, before he has even set the exact wire length of the loop!
Heard Karl today from DM/BW-088 and it was a better signal than from his G5RV and this with the Solar radiation hit that we apparently had this morning.
73 Ed DD5LP.