Hello Jim, 3x fast relays, 2x switching transistors, 3x resistors and box with connectors... You have KD9SV front-end saver. No diodes, no RX performance degradation. I never had issue on my K3 with KD9SV saver in ext.RX front-end. Let me know I will send You the drawing.
Hope it helps my friend, best regards, 73 - Petr, OK1RP http://160mband.blogspot.com On Fri, Jan 17, 2014, at 06:37 PM, James Rodenkirch wrote: > > > > A friend of mine is building me a switching arrangement with a reed relay > to switch between my transmit antenna and a receive delta loop to the one > antenna input for my Ten Tec Jupiter (I operate at QRP levels for > contests). > As an added measure of protection for the KD9SV low noise pre-amp I use > with my 160/80 delta loop antenna, he believes clamping the RX antenna > port or shunting to ground during TX sounds like a nice thing. But, he's > seen arguments that clamping receiver input with diodes degrades the > receiver performance. He find this believable, but I don't know how true > it is, e.g., he knows KD1JV claims his RX performance is achieved by > using 2N7000 FETs to do T/X switching. > He has a bunch of 2N7000 and will probably use one to turn on the relay. > He can turn on another one along with the relay driver that will shunt > the RX antenna port to ground but he wonders if that would degrade > receiver performance. > Thoughts? 72/72, Jim Rodenkirch K9JWV > > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband
