Hello fellow owners, I am posting this here in case it may help others solve some issues they have.
The past weekend contest presented a good opportunity to test a recent modification to my Elecraft XV432 transverter. In the last contest I noticed that its frequency stability was not sufficient for dependable FT-8 operation. As it went thru transmit cycles, the received signals on the waterfall would slowly arc over on a curved trajectory. It took about 15 minutes of operation to settle down I theorized that the high FT-8 duty cycle raised its internal temperature faster than its local oscillator crystal oven could compensate. The little fan inside simply spread the heat from the PA around to the whole unit. In a separate box I rigged a freq synthesizer (from Q5, having a nice TCXO) set to produce the required LO frequency. The LO in the transverter was disabled with a jumper from its transistor's base to ground. A BNC connector added to the side of the transverter near the internal LO circuit allowed for a small capacitor to then couple in the synthesized signal, and LO levels and alinement were similar to the original. It worked well! Now I get quick answers to my FT-8 transmissions. And, it is interesting to watch other's signals on the waterfall- some are obviously stable with a vertical series of transmissions, but others have curving trajectories, often seen when they would first start up on the band, and those stations were often difficult or impossible to contact as their frequency moved. My XV144 and XV222 transverters do not seem to suffer the same problem but will get a closer look in the future. 73, Chet, N8RA ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
