[evlatests] Tests on Variable Power output from Ant. 14 T304D

[Pete Whiteis]

    On a related note:   Jared Simon collected Power data from the 
L302's on the bench yesterday.   The plots he gave me show that power 
slowly drifts upward from 12.495 to 12.515dBm over ~4.5 hours.   The AGC 
loop then kicks in, brings power down by 0.020 dBm (to 12.495) and the 
whole cycle begins again. 
    If anyone wants to see the plots, I have them in my office. 

-P-

Rick Perley wrote:

>    Bob and I returned to antenna 14 today to do further work on
> the peculiar variable power seen last Tuesday from downconverter
> `D', in antenna 14.    The phenomenon was again seen, with the same 
> characteristics
> described on Tuesday.  We soon determined that the phenomenon
> is in T304-D alone, and is not seen in any of the other three
> downconverter outputs.
>    We also checked the stability of the L302 LO input:  over a
> twelve minute period, a drift of <0.1 dB was seen, and steps in
> power of ~0.01 dB were occasionally noted.   We are assured
> by Travis that such changes are far too small to account for
> the sporadic change in power level noted at the output of the
> T304D module.      As the weather was cloudy with thunderstorms, it 
> was not
> useful to measure system temperature (the clouds were adding
> a variable temperature of up to ~7K), nor especially any tests
> on the change of SNR throughout the signal chain.  We will
> have to attempt these next week.
>
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