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I have heard this System at 47Ghz, and it sounds like a free Running XTAL, there was a slight warble in two of the VCXO's, but NOT on another Frequency West Brick at 47Ghz. That Warble was present with, or without, the PLL attached and Locked, Obviously different XTAL's, the Regulator was suspect at this Freq. but the regulator has since been rulled out. The thing to remember is these 47Ghz LO Signals sounded EXACTLY the same UNLOCKED, but with Considerable Drift. Examples of 47Ghz with and with 200Hz Warble This file if from Mike, N1JEZ using Crystal at 121.5 MHz. x 96 = 11664. Then into a DB6NT sub-harmonic 47G mixer. Used a 432 IF (FT-817) Signal source was a Qualcomm "rectangular" board at 2616 into a Qualcomm multiplier board (non-powered!!) . Qualcomm was locked to a Z3801A GPS Osc. CPLD Versatile PLL was fed with a rubidium. Spectran Image of the above 200Hz Warble. Words from Mike, N1JEZ Below: One thing I find interesting in the Spectran plot I sent is how well the overall frequency is controlled. There is the obvious crystal woggle, but the overall trace is very nearly vertical. The red marks on the left are 60 second intervals.
The big squiggles you see in the middle of the trace was me checking the drive levels on the LO and Ref. It disturbed the lock, but you can see a quick recovery. Mike
Example of 47Ghz LO with 300Hz Warble This was using an Old ICOM 2??? with VFO, no Synthesizing at 144Mhz IF By Barry, Ve4MA. Locked to Z3801A GPS Osc. Example file is from Barry, VE4MA with 1 out of 3 Crystals that did NOT Warble, same set up as above, note slight drift in the Old ICOM with VFO,hi hi. More to Follow as time progresses,
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