[evlatests] Mystery Moon Test

[Ken Sowinski]

On Thu, 17 Dec 2015, Rick Perley wrote:

>    Rob ran the 'Moon compression test' last month at X-band.  The results 
> are bizarre:
>
>    1) We expect a power increment of about a factor of 5 to 8. This is what 
> was observed in the 'PSum' digital power.  So far, so good.
>
>    2) The 'set and remember' regimen was applied when the source was on the 
> moon.  The digital power level should be about 15, when on the moon.  This 
> was also the case.  Still good....
>
>    3) We then expect a 'PDif' compression (PDif on moon)/(PDif off moon) of 
> about 0.9.  In fact, this ratio was about between 0.1 and 0.4 (!!!!!)  That 
> is, for every antenna and every IF channel, the PDif when on the moon was 
> only 10 to 40% of the value when on cold sky.
>
>    This is a level of compressin that I have never seen before.
>
>    It may be worth noting that the PDif values, which are normally hundreds 
> of millicounts, where only 10 -- 50 millicounts.
>
>    Something is wrong.  Any ideas?

Did someone turn on the T302 solar attenuator?


>    Rob reports that the TPD values (recorded in parallel) were also weird.
>
>
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