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Old 7th May 2021, 3:15 pm   #174
SATOLEX
Triode
 
Join Date: Feb 2021
Location: Leiden, Zuid-Holland, The Netherlands
Posts: 26
Default Re: Spectrum Analyser TR4172

That is bad luck! I had the same with my IF1 module, after putting the analyser together it did not work anymore. In the beginning I thought that I had damaged the front-end. The 10 dB loss sounds like my loss problem. Check the inductor ground connections of the 206 MHz BPF in the RF part. Matt, I discovered why my LO2 power was too low. After tuning the LO2 chain I had more LO2 power. It is still less than yours but it is now +7 dBm at the output of the 1.84 GHz BPF which is going to the tracking generator. What I found in the manual is that this should be sufficient. Due to the higher LO2 power I also have more RF gain. So, relative to the -20 dBm calibration signal I have +3 .. -2 dB adjustment range. I also adjusted the 10 MHz time base reference and compared it with a 10 MHz GPS standard. I am still a little bit confused about the frequency reading. The -20 dBm reference is "exactly" 50 MHz if measured back with the GPS 10 MHz standard. The marker readout is telling me that the frequency is 50.0005 MHz. According the Freq counter function it is 50.002474 MHz and with Tuned Amp. Function (most accurate) it is 50.000000 MHz. Is this normal or do I have to calibrate other parts of the analyser?
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