Quote Originally Posted by N4VGB
How about one month spent running down a mystery noise on the output of a Heathkit Apache TX-1, that I'd already gone through completely and refurbed!!! :twisted:

I went through that thing with a microscope when I refurbed it, all functioned perfectly when completed, except for this very strange noise on the output that I could hear on a rcvr and see on the scope???

To make a very long story shorter, after stripping it down to only the bare crystal oscillator and VFO circuits, the noise was still there on both??? Hmmmmm? :chin:

A month later the source of the noise was discovered to be a battery float charger that I had "temporarily" put under the workbench and forgotten about. The noise was a feedback into the AC outlets on my whole workbench!
Don't you just hate that when it happens.

Like the RF interference I was having when troubleshooting the PLL in my IC-745. Yup the interference was everywhere....
Well chalk it up to the desk lamp, damned CFLs and their fifteen KHZ electronic ballast.