Thanks Dick and Howard... The RS-50 is pretty new - maybe 6 months old and is in daily use. It wasn't until I had a rig I could easily run on batteries did I notice the noise. The RS-12 is quite old, maybe 15 years? It had been in storage about 10 years until trying it out today. I think I need to dig into the RS-50 and just make sure everything is soldered and connected well.
As for common mode currents in the antenna... would that only be an issue during transmit? I have an OCF so I know it can be an issue on transmit. The OCF has a 1:1 current BALUN in the center. Is that enough or do I need to add some additional choking just below the BALUN? I have a couple of the NI4L line isolators (http://www.ni4l.com/hf-choke-line-isolator-1-8-300-mhz/). I could put one up there and see what it does. I also have plenty of clip-ons laying around. I'll try them on the power lead from the supply to the radio. The reports above were with *receive only* (with and without an antenna attached). On the RS-50 the hum I'm hearing is what I think I'd expect to hear from a less-that-well filtered linear power supply. The hash/hiss noise I hear sounds more like a switching power supply, which it is not. I don't know what in the power supply could be generating that noise. The RS-12 does not have either the hum or hiss that I can hear. It just sounds like the noise floor bumped up a little. I'm thinking Dick is right and it is just the receiver responding to the increased voltage though it is only about .5 volts above the external battery pack I was using. Is every power supply going to generate a little noise or should I expect no difference moving from battery to power supply? Kev ______________________________________________________________ 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 Message delivered to [email protected]
