Hello All,
Since a couple of days I have an annoying problem when operating 6m,
I have the power output limited to 30W, but sometimes I see the A-meter of my PSU going all the way up while transmitting. Power output and ALC go to max, no matter what, even without modulation. This happens on all modes.
I checked with a spectrum analyzer, and found out that when this happens, it outputs a high signal on around 47MHz, and nothing on the expected frequency. This happens irregularly, sometimes it is ok for hours, and suddenly it's not, for a couple of transmissions. Often it resets after a few transmissions.
I believe I have seen it on other HF bands as well, but recently I have only been able to replicate it on 6m. In any case, it seems to happen more frequently on 6m.
It looks like some oscillation is going on in the unit, causing maximum output on a wrong frequency?
I removed all the input and output connections (except the antenna and mike), but this does not change the behaviour. My antenna is reasonably well adjusted, VSWR <1,5. I haven't checked it with a dummy load yet, will do that later.
Does anybody recognizes this?
73
Peter/PA3FQH
