From: <Jim.Lovell_at_email.protected>
Date: Fri, 18 Mar 2005 10:09:50 +1100

Hi Adam,

Very nice! I have a few comments in addition to Tasso's:

1. Could you change Tid43 and Tid45 to Tid_70m and Tid_34m please? It's
a bit more descriptive as not everyone knows which DSS number
corresponds to which antenna.

2. At 2.3 GHz what Tsys are you assuming for the 70m? There are two LNAs
and one has a significantly better performance than the other (but only
30 MHz bandwidth). See
http://www.atnf.csiro.au/observers/docs/tid_obs_guide/tid_obs_guide.html#Receivers. For single polarisation and bandwidths of 32 MHz or less then the hempt can be used but for dual polarisation, both must be used. If it is dual pol then we generally switch the maser through a diplexer which raises it's Tsys a bit and makes it a better match to the hempt. So to summarise (!):
        single pol, bandwidth <= 32MHz : Tsys = 16K
        dual pol : Tsys = ~25 K
        bandwidth > 32 MHz (must be single pol) : Tsys = 25 K
This is all a bit beyond the scope of your tool, so see the next point:

3. How about a drop-down menu with all the standard S modes? (see
http://www.atnf.csiro.au/vlbi/observing/lba_s2_configs.html). This would
set the bandwidth and observing frequency accordingly and could also
select the appropriate Tsys for the 70m at 2.3 GHz. There could be an
"other" option which would let people set their own frequency and
bandwidth.

4. Is the baseline sensitivity quoted for the "Calibrator time/scan"
time? If so, that should be made clear.

5. Any reason why only a single ATCA antenna is available at 22 GHz? In
compact configs it may be possible to phase up some antennas.

6. Is it possible to show an estimate of the synthesised beam major and
minor axes plus position angle?

Cheers,
Jim

On Wed, 2005-03-09 at 22:00 +1100, Tasso Tzioumis wrote:
>Hi Adam,
>
>Marvelous tool! I had only a quick play tonight and it seems to work very
>well. A couple of comments:
>
>1. The sensitivities are reported to 4 decimal digits! Probably not known
>to better than 5-10% and should be reported accordingly. More than a
>couple of decimal digits are too much.
>
>2. We very rarely (ever?) tie all 6 of the CA antennas. 5 is the usual
>when the full array is used. I wonder if this should replace tied6 or
>include another button as tied5. I have no strong preference.
>
>Thanks for all the work
>
>Tasso
>
>On Wed, 9 Mar 2005, Adam Deller wrote:
>
>>> Hello all,
>>>
>>> The promised LBA sensitivity calculator has been completed and is now
>>> ready to use. It can currently be found at:
>>>
>>> http://astronomy.swin.edu.au/~adeller/lba/LbaSensitivity.html
>>>
>>> Feel free to drop by and give it a test drive over the next few days.
>>> Once it has passed this final stage of beta testing, we can find it a
>>> permanent home on the LBA webpage and (i guess) announce it to prospective
>>> observers. Any bugs/suggestions, please let me know and I'll endeavour to
>>> incorporate them.
>>>
>>> Cheers,
>>> Adam
>>>
>
>----------------------------------------------------------------------
>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/ |
>----------------------------------------------------------------------
>

-- 
Jim Lovell,                                       Jim.Lovell_at_csiro.au
ATNF c/o RSAA, Mt Stromlo Observatory,            Ph: (02) 6125 6715
Cotter Road, Weston ACT 2611                      Fax: (02) 6125 0260
Australia                                         Mobile: 0412 127364
WWW: http://www.atnf.csiro.au/people/Jim.Lovell
Photoblog: http://jejl.blogspot.com
At Tidbinbilla Ph (02) 6201 7869 (RA Lab), x7800 (switch), x7940(shift)

Received on 2005-03-18 10:10:26