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Andrew2 · 27th Oct 2017, 11:42 am

I was building something-or-other a while ago and I ended up with an unused *but still powered* emitter follower onboard. It had a length of RG174 coax on its emitter. I'm sure we can all see what's comng!
The project was showing some nasty behaviour and some strange noises-off. And I noticed a large spike on the analyser around 100 MHz. It was remarkably stable. It turned out that the emitter follower was happily honking to itself at a frequency determined by the length of the coax.

27th Oct 2017, 11:42 am	#71
Andrew2 Nonode Join Date: Mar 2010 Location: Dukinfield, Cheshire, UK. Posts: 2,038	Re: Spectrum Analyser I was building something-or-other a while ago and I ended up with an unused but still powered emitter follower onboard. It had a length of RG174 coax on its emitter. I'm sure we can all see what's comng! The project was showing some nasty behaviour and some strange noises-off. And I noticed a large spike on the analyser around 100 MHz. It was remarkably stable. It turned out that the emitter follower was happily honking to itself at a frequency determined by the length of the coax. __________________ Andy G1HBE.