[Elecraft] XG50 - Frequency Instability

[Alan Bloom]

50-60 kHz instability of a 49 MHz source is over 1000 ppm, two or three 
orders of magnitude greater than would be expected, even with air 
conditioning blowing across the oscillator.  There must be something 
wrong with the XG50, or perhaps some problem with the frequency measurement.

Alan N1AL


On 05/22/2014 07:31 AM, kj7rt at kj7rt.com wrote:
> I am trying to use my XG50 to run the Extended Temperature Compensation
> Procedure on my KX3. This is the first time I have attempted to use the
> XG50 since building it. I have completed the 8 hour burn-in.
>
> When I first connect the XG-50 to my HP frequency counter, I get a
> reading of something like 49.379990. Then after running for several
> minutes it starts dropping in frequency to something more like
> 49.32xxxx. It is still wildly fluctuating. If I connect the 10MHz output
> of my Trimble Thunderbolt GPSDO to the counter it stays quite stable
> just below 10 MHz.
>
> I re-soldered all the XG50 components and tried with both a metered
> home-brew power supply and a 12v SLA battery with the same result
> although re-soldering made a significant but not permanent improvement.
>
> My lab is in my photographic darkroom which has an ambient temperature
> of about 68 degrees F and the AC does blow across the work area.
>
>
> Thanks,
>
> Gary Marklund
> KJ7RT
> Sun City, AZ
> USA
>
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