[evlatests] Alerts for T304 TPD levels

[Jim Jackson]

While we may be able to add alarms or some more intelligence in the 
T304 ALC routine, I think we will hit a limit of what can be dealt 
with using just the T304 power detectors to set levels.  For the 
bands with lots of  RFI, it seems like we really need to start 
considering setting the T304 attenuators based on results from the 
digitizers and/or various stages of the correlator.

Jim

At 09:28 AM 4/5/2011, Chuck Kutz wrote:
>Somehow we are going to have to come to grips with working in a contiguous
>RF environment.
>
>This solution has the possibility of generating a lot of write ups that
>someone will have to spend time on.
>The system as currently implemented, is "fooled" by spurious RF signals that
>affect the level set which is based upon the total energy observed in a 1GHz
>wide RF environment.
>
>There may be other ways to handle this. I have a couple of ideas. Anyone
>interested?
>
>
>Chuck
>
>-----Original Message-----
>From: evlatests-bounces at nrao.edu [mailto:evlatests-bounces at nrao.edu] On
>Behalf Of Keith Morris
>Sent: Tuesday, April 05, 2011 8:12 AM
>To: Steven Durand
>Cc: evlatests at aoc.nrao.edu
>Subject: Re: [evlatests] Alerts for T304 TPD levels
>
>There is certainly the possibility of false alarm, but the cost of such
>an alarm is quite low.  The TPD monitor point message field reports the
>ALC status-- target reached, attenuator out of range, etc.  The alert
>would inform the operator that such a situation exists; there may or may
>not be any action the operator can take.  But in the cases where the
>attenuators failed to set up properly, the benefit of having a second
>chance of dialing in proper levels may outweigh the inconvenience of
>false alarms.
>
>
>
>Steven Durand wrote:
> > Is there the possibility of many false alarms.  The x-band
> > receivers still have very low output.  Also at the edges of each
> > band some of the receivers have low output that can not be
> > adjusted to the proper level.
> >
> >
> >
> > Rob Long wrote:
> >> I discovered several T304 attenuators set incorrectly (again) this
> >> morning. I wonder if we should setup alert levels on the TPD monitor
> >> points in order to warn operators of a potential ALC problem. If the
> >> operators knew of the problem, they might have been able to take
> >> corrective action.
> >>
> >> I spoke with Dave who informed me that they didn't even realize the
> >> attenuators were set incorrectly because they saw no fringe problems.
> >> This email is effectively a channel to open communication concerning
> >> ideas/solutions to this problem!
> >>
> >> Thanks,
> >> Rob Long
> >>
> >> _______________________________________________
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> >> evlatests at listmgr.cv.nrao.edu
> >> http://listmgr.cv.nrao.edu/mailman/listinfo/evlatests
> >
>
>--
>Keith Morris
>National Radio Astronomy Observatory
>1003 Lopezville Rd.
>Socorro, NM 87801
>575-835-7060 (phone)
>575-835-7027 (fax)
>
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