Joe, I can only confirm what Jim has written and this undermines my findings.
Putting ferrites in the Original Microham cables improves the situation but does not solve it. I got feedback with similar problems when antennas are in close proximity, again only with Microham interfaces. Others work Be happy when in works in your environment. Lets close this thread, I found my solution that works but lost confidence in the Microkeyer II. 73s Bernhard -----Ursprüngliche Nachricht----- Von: Joe Subich, W4TV [mailto:[email protected]] Gesendet: Dienstag, 16. Februar 2016 14:55 An: [email protected] Betreff: Re: [Elecraft] Microham Microkeyer II, RFI in mike with my K3 Jim, On 2/16/2016 2:04 AM, Jim Brown wrote: > Indeed, it would darn near impossible to do it right without starting > from scratch withunit a properly made cable from the MicroHam unit to > the radio, with each signal path having its own coaxial cable. Please confine your comments to areas where you are knowledgeable. The microHAM cables *DO* use a separate coaxial cable (or shielded twisted pair) for each signal path. The shields are connected to the shell of the respective connector on each end of the cable. With properly designed transceivers, this design will minimize RFI issues. When good engineering practice is used in the station installation - including antenna systems - there should be no RFI problems with a properly implemented microKEYER II, MK2R+ or micro2R system. Schematics for every microHAM cable are available from the support area at www.microham.com or www.microHAM-USA.com/support.html. 73, ... Joe, W4TV On 2/16/2016 2:04 AM, Jim Brown wrote: > Bernhard, > > It's NOT common mode, it's the simple fact that the audio interface is a > mess. The antenna on the roof transmitting high power is doing its job, > putting a lot of RF in the shack. If it didn't (based on proxmiity), it > would be a lousy antenna. The problem is that the interface (wiring plus > electronics plus termination) does not reject RF because it fails to > conform to fundamental principles that reject RF. That is, every cable > must be a transmission line, every shield must be terminated at the > shielding enclosure of the equipment at both ends, and every equipment > chassis must have a short, fat, bond to every other equipment chassis. > Yes, the signal is audio, but the interference is RF, and it takes > proper transmission line techniques to reject that RF. > > I have VERY limited experience with MicroHam, but the jumble of wires > that I encountered with the MicroHam unit at W6OAT violated all > principles of good engineering practice for operation in a high RF > environment. It was nothing more than a multipin connector with a lot of > wires soldered to that connector. Indeed, it would darn near impossible > to do it right without starting from scratch withunit a properly made > cable from the MicroHam unit to the radio, with each signal path having > its own coaxial cable. > > I have no idea if that describes ALL MicroHam units, but it does > describe Rusty's. And don't ask the model number -- I was so disgusted > by what I saw that I just rolled my eyes. > > 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 Message delivered to [email protected]
