[evlatests] ea20 gain variations

[Rob Selina]

Hi Rick, 

No obvious issues with HVAC, plots attached for Sunday. 

Mapping of monitor points courtesy of Jerry Langevin:

P301-1-EXT2 > Vertex Room Ambient
P301-1-EXT1 > LO/IF Rack, between door and modules. 
P301-2-EXT1 > LO/IF Rack, Input plenum
P301-2-EXT2 > LO/IF Rack, Exhaust plenum
P302-1-EXT1 > Utility Rack, above D301
P302-1-EXT2 > Utility Rack, above D303

Any other suggestions to look into?

Cheers,
Rob


-----Original Message-----
From: evlatests [mailto:evlatests-bounces at listmgr.nrao.edu] On Behalf Of Rick Perley
Sent: Tuesday, January 19, 2016 2:10 PM
To: evlatests at aoc.nrao.edu
Subject: [evlatests] ea20 gain variations

     I noted last week how the switched power system nicely corrects gain changes at X-band.

     In another 'beam holography' run, taken Sunday evening at 6cm, the same type of gain variations noted earlier in ea20 at X-band are present in that antenna at C-band.  I attach a plot of the 'PDif' values.  The gain variations are significant -- about 10% in power. The timescale is about 1 hour.

     I would guess that something is quite amiss with the temperature control, since this behavior is seen on (at least) two different bands.


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