[asac] forwarded message from owner-asac at kochab.cv.nrao.edu

[Al Wootten]

For some reason, the mailer bounced Geoff's email, which I forward:

Hi All,

  I believe Ewine's earlier mail summarized the 15 minute issue with the
receivers and it is the following.  Three receivers (the WVR plus two
astronomy receivers) can be on at any one time. The 15 minutesis the time
needed to get a receiver up and going from a COLD start. It takes a bit
for the amplifiers to warm up and stabilize, etc. I suspect things like LO
switching and so forth are very much faster.  So, the question is, if you
have two receivers that are on, and you need to switch to a third, how
much will that limit the available science.  If this is a serious issue,
we should let the receiver group know very soon that we are concerned with
this length of time.
  I would note to Min that if there are a few sources that are close
enough that the switching (i.e. moving and pointing) time is short, you
can do a few sources with the active receiver while the new tuning warms
up, so I find it hard to believe this will be a very serious limitation.

  Geoff

__________________________________________________________________________
Geoffrey A. Blake; Professor of Cosmochemistry & Planetary Science,
                   Professor of Chemistry, and Deputy Director,
                   Owens Valley Radio Observatory      gab at gps.caltech.edu