UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Directional coupler

cmjones01 · 28th Nov 2017, 12:56 pm

Thank you for the very comprehensive analysis. Jeremy, your hypotheses about the analyser's architecture are spot on. The 1st LO is a 2.095-3.9GHz YIG, which has phase locking at spans of 100kHz/div and less. The 2nd LO is a 2.2GHz +/-1MHz and is swept only on narrow spans.

I'll try some experiments. Firstly, fitting a terminator to the 1st LO output and seeing if it makes any qualitative difference to the analyser's behaviour. Then I'll try and have a look at the amplitude of the 1st LO output, though the only tool I have for that is a sampling scope so there may not be enough amplitude to get it to trigger. If it works, though, that might give us some idea of the coupling factor of the mysterious component.

Chris

28th Nov 2017, 12:56 pm	#7
cmjones01 Nonode Join Date: Oct 2008 Location: Warsaw, Poland and Cambridge, UK Posts: 2,679	Re: Directional coupler - terminated and unterminated Thank you for the very comprehensive analysis. Jeremy, your hypotheses about the analyser's architecture are spot on. The 1st LO is a 2.095-3.9GHz YIG, which has phase locking at spans of 100kHz/div and less. The 2nd LO is a 2.2GHz +/-1MHz and is swept only on narrow spans. I'll try some experiments. Firstly, fitting a terminator to the 1st LO output and seeing if it makes any qualitative difference to the analyser's behaviour. Then I'll try and have a look at the amplitude of the 1st LO output, though the only tool I have for that is a sampling scope so there may not be enough amplitude to get it to trigger. If it works, though, that might give us some idea of the coupling factor of the mysterious component. Chris __________________ What's going on in the workshop? http://martin-jones.com/