From: <Tasso.Tzioumis_at_email.protected>
Date: Thu, 12 May 2005 01:25:11 +1000 (EST)

Hi everyone,

I'm at Mopra checking out the system in preparation for the VLBI. I've
just checked the 1.6 GHz band that we used for VSOP and the interference
from Iridium/Globalstar in the 64 MHz input band to the DAS is still quite
strong.

This does not affect the recorded band BUT it does affect the wideband
Tsys measurements. Here at Mopra the Tsys can vary by a few K between
10sec cycles that the system uses here.

It is possible (with some rewiring) to measure the Tsys in a narrower band
while recording via the 2nd frequency chain. This can be done easily at
the ATCA and with some manual recabling at Mopra (and a change in the
local schedule). We used to do this for VSOP.

I guess it does not matter much for the VT tests to NZ. The only other
experiment affected is V172C. I do not not know what the experience was
with V172a and V172b. Does this need accurate Tsys? Note that the
changeover is around 4am! But if you do need to calibrate the data
accurately we should try it.

Any comments from the PI? Giuseppe?

Cheers
Tasso

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Tasso Tzioumis, Australia Telescope National Facility, CSIRO |
Location: Cnr Pembroke & Vimiera Rds, Marsfield, NSW, 2122, AUSTRALIA |
Post: PO Box 76, Epping, NSW 1710, AUSTRALIA |
Phone: +61 2 9372 4350 Fax: +61 2 9372 4450 or 4310 |
Email: Tasso.Tzioumis_at_csiro.au |
URL: http://www.atnf.csiro.au/~atzioumi/ |
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Received on 2005-05-12 01:25:31