|PA1PRD's endfed tuner|
I always wanted to experiment with this design to feed my horizontal loop. Since the system works with a simple transformer the radio is not physically connected with the antenna and that's one of the things I like of this design. Other advantages claimed are better balance compared to a T-Match with 1:4 balun and a higher antennacurrent into the antenna. So, I aquired a homemade matcher from PA1PRD Erik at a sale from our radioclub. It is a very simple endfed tuner which he used for a 80/40m wire hanging in the air below a kite. Both coil and capacitor are homemade. Just perfect for my little project. I dismantled the whole thing and made some improvements on the capacitor.
Measuring everything I was already afraid I would have too less capacity (140pF), but for just a experiment it's not a problem. I don't bother you all with the technical aspects of building this whole antennatuner but in the end it cost me a "few" hours. What was more important to me were the results. I wanted to verify the claims given. At first I measured the current behind my Palstar AT2K which is a T-match with built in 1:4 balun. Transmitting with 40W FM I measured about 0,8A on one side and 3,4A on the other side of the open line with my clamp meter.
I connected the S-Match© and with the help of my MFJ-259B I found a nice 50Ohm match on 30m. Oh yes, with 40W input I measured again and found a high current of 300A on one side and 80A on the other end. This couldn't be true. Besides that, the radio kept transmitting even when I switched PTT off. Not good. I decided to listen how receive was and it was not that good.
radioamateurshop.nl which is not really a shop although it is in the name. It is a repairservice for hamradio equipment. So I already shipped the analyzer and hope it will be repaired soon.