Last night I was talking with a local on 222 SSB, and I noticed most of the lights on my XV-222 bar graph were staying on in TX, like it was in a peak-hold mode. At the same time I noticed Hi-RFI alarm coming up on the K3 display while transmitting. A quick check and everything seemed tight, SWR was good, and no other rigs were on (at least in TX). I did look at some of the reported RFI cases here on the reflector, but they seemed to be RFI into the XV-222 from other rigs.
So, I popped it on my spectrum analyzer and, while transmitting, there it was, a strong osciilation at about 300 MHz. Now, with 222 present it swamps the oscillation so when you're sending CW, the oscillation is present between the character spaces, and on the watt meter all you see is around 15-20 watts output. Or like FSK with a 78 MHz shift. Next I popped off the XV-22 top cover and of course the problem was gone. I suspected that there was coupling from the PA output into the top cover and back into an earlier stage causing this instability. In fact, I can hold the cover in my hands, and covering just half of the XVTR PA and it starts oscillating. Has anyone seen their XV-222 unit oscillate during TX (sans an applied 222 signal)? Oh, yea, everything has been sanded and grounded per the instructions and as suggested by Wayne in the RFI emails. Has anyone seen this on their unit? Is there a tech note or app note out there on this? Thanks in advance. 73 Mike K9MK/5 Haslet TX. ______________________________________________________________ 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
