I have a Hamshop.cz Trapped EFHW for 40/30/20m. I acquired it several FN rallies ago (2017?) as I had some Czech Crowns left from a trip and Juerg HB9BIN recommended it.
It works, I’ve used in France, Germany, Czech Republic, Poland , Switzerland when doing light-weight activations. (Simple walks, small hills etc. outside the UK) But I don’t know if it works well or not. Yes, I make QSOs but I don’t know if it’s better or worse than a centre fed dipole. I only use it when I don’t want the extra hassle of using coax. Sometimes it seems to be good and sometimes not. But as I have nothing to compare it against at the time I don’t know if it’s conditions or not. What I have found is that it seems to work better when either in inverted-L with the about 4.5m vertically up the pole and the rest out horizontal (maybe tied in a tree) or with the end sloping down to about 1m above ground tied to a small stake.
What I noticed on HB/ZH-017 when I was dismantling it was the matching unit was hot. It was about 29C that day and the toroid was very much hotter. Not too hot to touch but hot. Well that’s my RF heating the toroid rather than getting into the antenna! The match is a toroid core with 2 windings, there’s space for a capacitor on the board but none is fitted. The traps have a T50-6 (maybe?)with a winding and surface mount capacitor. My 817 reports more than acceptable SWR for the 3 bands but dressing the antenna is important for best match on 20m.
The question is… should there by some C on the match unit? Or should I make up my own match (AA5TB) and replace the provided one?