[R-390] eBay Funny of the Week

[Shoppa, Tim]

Once, in trying to build a VFO, I managed to get the 6AH6 to squegg. It was producing no less than 3 distinct frequencies in very complicated waveforms:

1. The desired oscillation on the desired frequency (3.5 MHz) would start to build up.

2. A UHF parasitic (near 400MHz) would kick in as the 3.5MHz waveform built up and quench the oscillation.

3. Above cycle would repeat with a rep rate in the low kHz.

Why the handbook recommended a hard to stabilize UHF tube for use as a HF VFO, I never understood. I think it was there that I learned that mere specsmanship (looking up the tube with the "most" and "highest" in the tables) often does not produce a working design.

Later on, in photography, I discovered the misguided efforts of "low grain" or "no grain" films. Compare the lack of good pictures taken with Panatomic-X with the number of good pics taken with Tri-X :-).

> Subject: [R-390] eBay Funny of the Week
> Item # 220448638702
> Barry - N4BUQ

Tim N3QE