[evlatests] EVLA Hardware

[Rob Long]

I talked with Chuck about this and that is exactly what we saw on both 
antennas 11 and 21.  We have measured spurs (nice and steady) at 6.7 GHz 
and 6.9 GHz.  Disconnecting the cal/monitor and control cable from the 
Utility rack for P-band makes the spurs (and their harmonics) disappear. 
  We did not power down the P-band receiver, just disconnected the 
previously mentioned cable.  We left this cable disconnected when we 
left and C-band on both antennas seems to behaving nicely now on all 
IFs.  Chuck is planning to try and reproduce the effect we saw in the lab.

Rob

Jim Jackson wrote:
> Remember that the receiver and T302 have a considerably wider bandwidth 
> than the 1 GHz bandwidth of the samplers.  We have had P-band receiver 
> birdies before that did not show up in the bandpass plots at the default 
> LO frequencies. In fact I think that was the case the very first time we 
> saw this - the birdies were around 6 or 7GHz.
> 
> Jim
> 
> At 07:45 AM 10/4/2007, Charles Kutz wrote:
>> Also and very importantly, we did not see any P-Band "birdies" in the
>> passbands.
>>
>> Chuck
>>
>> Rob Long wrote:
>> > Chuck and I set up ant 11 at C-band and Ken is right, the T304 
>> levels do
>> > not look correct!  We will probably have to make a trip to the antenna
>> > tomorrow to see what's going on.
>> >
>> > The Deformatter rack for ant 1 (and all following antennas) has been
>> > installed in the new correlator room.  It has power (but was unplugged
>> > after it was checked out), RF signal cables, etc. and will be ready for
>> > use as soon as Linda installs the fiber cable from the optical demux to
>> > the deformatter rack (probably Monday).
>> >
>> > Rob
>> >
>> > _______________________________________________
>> > evlatests mailing list
>> > evlatests at listmgr.cv.nrao.edu
>> > http://listmgr.cv.nrao.edu/mailman/listinfo/evlatests
>>
>> _______________________________________________
>> evlatests mailing list
>> evlatests at listmgr.cv.nrao.edu
>> http://listmgr.cv.nrao.edu/mailman/listinfo/evlatests
>