Hi Jim, Thanks for the reply. I have not noticed any power fluctuations or increases in reflected power during the alarm event.
Antenna system is a Tarheel 100A screwdriver mounted on a tripod on my balcony. The balcony is about 40 feet away from the station. The antenna is fed with good quality Times Microwave LMR-400UF. The last 20 feet of it were wound into a common mode choke using 4" PVC. The antenna does not have a very good radial system; about 10 strands of 20g wire cut to about 12 feet in length. I do have a 66' length counterpoise but have not laid it yet due to the size restrictions of the balcony (5' x 12'). The antenna's control cable was also decoupled via a ferrite choke. Again, 1100w constant carrier doesn't cause this problem. Only keying up when the K3 is in a sideband mode. Keying up with drive power from the K3 at 100w or 50w doesn't make too much of a difference; the alarm will trip at random times. Dropping the drive power to about 12 watts seems to prevent the alarm from tripping. This phenomenon does not happen if the amp is off line. The wattmeter is one of MFJ's new digital/analog deals. It's the MFJ-828. Please clarify the K3 pin 1 issue; I do not have my assembly manual in front of me. 73 de James K2QI > > On Tue, Jul 14, 2009 at 5:43 PM, Jim Brown > <[email protected]>wrote: > >> On Tue, 14 Jul 2009 13:44:00 -0400, K2QI wrote: >> >> >I am curious though; your previous email mentioned rectification of audio >> in >> >the wattmeter, feedline or antenna. >> >> As noted, one or more good common mode chokes are in order. You mentioned >> the >> lack of a station ground. That is a lightning safety issue, but NOT a >> solution >> to RFI. >> >> You didn't mention what your antenna system is, or how far it is from the >> rig. >> >> The important question is, is this only RFI to the wattmeter, or is >> something >> else going on, like a spur or harmonic? Have a ham nearby listen for spurs >> (or >> take the antenna off another radio and listen for spurs). >> >> Is this an outboard wattmeter, or something built into the power amp? If >> outboard, my first move would be to replace the fancy wattmeter with a >> Bird, >> and look for fluctuations indicating increased reflected power. If you >> don't >> see any, I would blame the meter. If you DO still see the fluctuations, I >> would >> look at the K3 and the power amp. The K3 does have some pin 1 issues. >> Ferrite >> chokes would help with that. >> >> http://audiosystemsgroup.com/RFI-Ham.pdf >> >> 73, >> >> Jim Brown 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 >> > > ______________________________________________________________ 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
