On 3/21/2012 12:24 PM, Matt Murphy wrote: > Just wondering if anyone has any experience using two K3's on the same band
YES! My first experiences were on county expeditions for the California QSO Party, with four K3s feeding two KPA500s, a Ten Tec Herc II, and a 600W Yaesu amp. We had tribanders pointed roughly 70 degrees, carefully located so that they were at 90 degrees to each other, and were able to run one on CW with the other on SSB on the same band on 15 and 20M. The stations would hear each other at about S6-7, so we could work the roughly 60% of signals that were louder than that, then we would have one change bands so that both could work the weaker ones. At home, I have a 3-el SteppIR at 120 ft on one tower, monobanders for 20 and 15 at about 40 ft on a tower about 150 ft away, and a 4-el 10M Yagi about 50 ft further from the SteppIR. During contests, I run Ten Tec Titan amps at legal power with two K3s. All of my antennas are fed with either CATV hard line or Heliax for most of their run, and everything else, including all patch cables inside the shack, is on very good RG213 with soldered Amphenol PL259s. With those Yagis optimally aimed to reject each other, I can operate as close as 50 kHz on 20, 15, and 10 and not know the other station is there. Pointing one at the other is another story, and can cause the receiving K3 to turn off the preamp and turn on the attenuator, but I can still work strong stations through my own QRM. I mentioned the quality of my coax because that is quite important when you're trying to get a lot of rejection. Poor connections, or poorly shielded coax, or both, can couple common mode current from the outside of the coax to the inside of the coax at low levels. Coax shielding is a function of the resistance of the shield, the density of the shield, and the uniformity of the shield. Thanks to skin effect, the larger the diameter of the coax the lower the RF resistance of the shield, assuming a shield of the same quality. 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
