I have also used bi-directional 1N4148 diodes across the antenna path, but I'm re-thinking that approach - If the diodes are not preceded by a good bandpass - or at least, a hipass filter in the antenna lead, I'd be concerned in some instances about the possibility of intermod from nearby, or strong BC stations.
73, Charlie, K4OTV -----Original Message----- From: Topband [mailto:[email protected]] On Behalf Of Mike Waters Sent: Sunday, August 30, 2015 3:52 PM To: Charles Cunningham Cc: topband; Tom W8JI Subject: Re: Topband: KD9SV-OK1RR relays ??? How about back-to-back 1N4148 diodes (2 in series) across the RX path, and a #47 incandescent lamp between those and the Beverage? That's what I do here, among other things. Those are in series with my preamp, which is almost always on. There's also some variable resistance in series with the lamp and the Beverage switching relays. I do that so that the signal from the Beverage is equal with the RX signal from the inverted-L. 73, Mike www.w0btu.com On Sat, Aug 29, 2015 at 8:06 PM, Charles Cu nningham < [email protected]> wrote: > > It seems to me that a very fast operating preamp protection circuit > could be constructed employing a good fast saturating NPN switching > transistor across the antenna path. > _________________ Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband
