[evlatests] A curiosity with antenna 12

Hichem Ben Frej hbenfrej at nrao.edu
Wed Jun 30 19:25:07 EDT 2010


According to the log, the M301 on antenna 12 has been updated with 
verion 0.20 on April 21st.
Looking at the MAC I found out that the MIB is different.
At the time the M301 module on antenna 12 was 000C690003AA. The current 
MIB is 000C690003B7.
It looks like the module got replaced some time.

--Hichem

Jim Jackson wrote:
> 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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