ham-it-up 125mhz not working

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Miku Hatsune

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Jul 6, 2015, 3:32:36 PM7/6/15
to open...@googlegroups.com
Trying to get my new ham-it-up 125mhz to function.

Checked the voltages, etc per the other posts, they all appear to be correct.

In passthrough I see big 125mhz peak. In upconvert, I see no additional peak.

Voltage across R2 is 0.75V. Voltage across oscillator pins looks correct for upconvert/passthrough.

If I inject signal direct with signal generator, I can see upconversion being done, but it is very weak. 10khz 0.2v doesn't even show up. I have to move it out to ~200khz. And then it shows up around -58db.

Antenna seems operational in passthrough. I can receive clearly FM, VOR, etc.

opendous

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Jul 6, 2015, 4:14:03 PM7/6/15
to open...@googlegroups.com, parkxz...@anime.net
> In passthrough I see big 125mhz peak.
> In upconvert, I see no additional peak.

  That is backwards.  The peak should be in Upconvert mode.  NooElec had a small batch of enclosures with the labels reversed.

  Assume the 125MHz peak only occurs in Upconvert mode and that the switch might be backwards.


> 10khz 0.2v doesn't even show up.

  10kHz is too low to get through.  ~33kHz would be -20dB lower than at input.  The Upconverter is specified to 100kHz at the lower end where losses should be about 10dB.
http://code.google.com/p/opendous/wiki/Upconverter#125MHz_Upconverter_Upconversion_Losses


> I have to move it out to ~200khz.
> And then it shows up around -58db.

  A 0.2Vp-p (peak-to-peak) (or 0V-to-0.2V) signal is about -10dBm.  At the Upconverter output it should be showing up as 125.2MHz at about -20dBm.  -58dBm is too low.  Is this occuring next to the 125MHz peak?
http://ifmaxp1.ifm.uni-hamburg.de/DBM.shtml

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