Hi All.... I recently bought a non-working Advantest 2.6GHz spectrum analyzer on eBay. Turns out the front attenuator diodes were fried along with the first mixer diode. I bought the resistors from Digikey and found a suitable replacement diode again on eBay. Still no signal display. The analyzer uses a mixer with the local oscillator running 2.6 GHz
higher than the input signal, so the LO runs at 2.6-5.2 GHz. Since that was a possibility of no signal display, the manual says to check the frequency and amplitude. Well, nothing in my basement workshop, or at my work either, will measure anything that high. I thought of trying to make some kind of detector circuit from one of the mixer diodes I bought, just to see if the LO was present. I was guseeing that if its there, its probably correct. Then it suddenly dawned on me... I HAVE a microwave detector already! Went out to the garage and found my old radar detector that I used to use in the car. I fired that up with a 12VDC supply and put the antenna side directly over the mixer coupler. Viola' ! The radar detector sang like a bird! Now again I couldn't measure the frequency, but it was there! I managed to find out the remaining problem and now the analyzer seems to work fine. Just thought I'd pass that on in case anyone else could use it.
sherlock
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