Re: Spectrum Analyser conundrum

Andy G4JNT

Not really.   The Rado Test set / 6GHz SA is a nice narrowband analyser, going down to 1Hz resolution.  It's a digital FFT based system.   SO the last thing I want to do is use an LO that wobbles by even a few hundred Hz.  My main interest is narrow band spectrum analysis.

As for a converter, the only YIG needed in there is the YIG fiilter to kill spuris mixer responses when used as a subharmonic mixer.   Need to find some way of tying in filter tuning with the display.  A PC is going to be involved in the loop I suspect.

On Wed, 22 Jan 2020 at 10:47, geoffrey pike via Groups.Io <> wrote:
Would you not think of using a YIG oscillator instead of a synth?

On Tuesday, 21 January 2020, 20:27:05 GMT, Andy G4JNT <andy.g4jnt@...> wrote:

Openly Pondering ...

My Ailtech / Eaton 757   22GHz spectrum analyser has died.   Now, I could just dig inside and repair it - looks like the main PSU has failed somewhere, so probably is repairable, and I hate repairing stuff, especially old tech.   ANd then there's all the niggly faults which appeared over time, probably dried out capacitors to be  replaced.   The thing weighs over 30kg has already hurt my back in days gone by and is too long in the tooth and irritating to drive

I'd buy a half- decent SA but many popular ones only go to a few GHz and 22GHz ones are not cheap. I already have a modern digital radio test set that has a quite good narrow band SA function that goes to 6GHz  with span up to a GHz, so spending a fair bit of money on an SA that doesn't go much beyond this seems totally pointless.

NOW ...

I have two old YIG filters that tune 4 - 18GHz.  The Ailtech will have another one inside it, as well as a harmonic mixer so thoughts are turning to an external converter.    YIG filter, harmonic mixer and integer-N synth LO with some basic drive electronics.   Simple enough.   Could butcher the old SA for it's harmonic mixer, or make one using a uWave DBM with subharmonic LO.  It also has the switchable attenuator going to 20GHz + and possibly other uWave bits that may prove useful

So the decision to repair (tedious and not exciting) or rip apart for bits to make an external converter has to be made,

Has anyone done this - an external SA convertger?   Might generate a bit of interest in building RF stuff again here !


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