On 2/20/2012 10:01 AM, Allen Brier N5XZ wrote: > My question is, how much receiver rejection and/or overload should I expect? > He pretty much tears up the entire band on my K3 if my antenna is pointed his > way, but not quite so bad on the side. On my P3, the entire noise floor is > raised many S units (I'll have to switch to dB and see what it looks like.
It will depend a LOT on what rig and amp he is using, and how he tunes (or mis-tunes) his amp. A K3 is REALLY good at rejecting off-frequency signals, but there are a lot of rigs and amps that fill up the band(s) with trash AWAY from their frequency. In contests, I run two K3s, each feeding a Titan 425 amp at about 1.2kW, into mono-band antennas that are about 150 ft apart. On 20M and above, they are 3 and 4-element Yagis. Depending on how those antennas are pointed, I can have them as close as 60 kHz ON THE SAME BAND and one K3 does not know the other one is there! On the other hand, if I point either of those antennas at the other, I'll hear a lot of my own phase noise, and the K3 will automatically turn off the preamp and kick in the attenuator. Now, the smallest coax in my station is very good RG8/213 and RG11, some of it is CATV hard line and Heliax, all the connections are carefully hand soldered to Amphenol connectors, I'm careful about how I tune the amp, and I don't use AGC between the amp and the K3. We also use three K3s for our county-expedition during the California QSO Party, and on 20, 15, and10, have two tri-banders set up about 150 ft apart, carefully located so that when pointed east, they are at 90 degrees to each other. We run 500W amps, and this past year one of them was a KPA500. We also used an ACOM and a Yaesu amp. With that setup, we could have both CW and SSB stations on the same band and one would hear phase noise from the other at about S6-S7. Coax is typically a grab bag of what's everyone's spares, and a lot of it is crimped from a popular ham vendor. I've got an 80-year old neighbor about two miles south of me who works SSB contests by calling CQ non-stop as long as he's awake. I have no idea what he's using for a rig or amp, but he wipes out all of whatever band he's on with phase noise and intermod. My neighbor, K6XX, is 3 miles away, and runs K3s to several different f ancient amps. We can work 500 Hz from each other on any band. Another neighbor 10 miles away runs an Icom 7600 into a big amp and sometimes wipes out 20 kHz with his phase noise and clicks. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
