[evlatests] Mystery Moon Test

[Rick Perley]

     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?

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