[evlatests] A curiosity with antenna 12

[Jim Jackson]

Antenna 12's M301 had the wrong version of firmware in it.  It was 
the version we installed in early April that was pulsing the switches 
every time a command was received. I don't know why this module 
didn't update when the rest of them were done on 21 April - possibly 
the antenna was being worked on and wasn't communicating.  It has now 
been fixed and has the same firmware as the rest of the M301's.

Jim

At 04:48 PM 6/29/2010, Ken Sowinski wrote:
>On Fri, 25 Jun 2010, Rick Perley wrote:
>
> >    Michael took a short (27 minute) observation in 2 GHz-wide mode a
> > couple days ago.   Eight full-polarization subbands, each of 128 MHz
> > width, in each of the AC and BD IFs.  In general, beautiful data.
> >
> >    It was noted that antenna 12 had a curiousity -- once every minute,
> > on all subbands, in all polarizations, the amplitude dropped by about
> > 10% for a single 1-second record.  This was the only antenna for which
> > such a effect was noted.  As the script asked for a new scan every
> > minute, I had assumed the 'drop-down' was a first-record, or perhaps
> > second-record problem.  It's not!
> >
> >    This 'drop-down' is a 2nd-record effect -- the 2nd record of every
> > scan is low by this much.
>
>this is still happening.  It is really synchronous with the
>the new scan and is happening at the antenna.  The evidence
>is that all the T304 power meters show a one or two dB dip
>at each scan.  Since it is seen in the input power meter it
>must be happening upstream of the downconverters.
>
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