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ATCA Sensitivity Calculator

PostPosted: Tue May 04, 2010 11:56 am
by len067
Hi All,

I had a question with regards to the ATCA Sensitivity Calculator when using it to estimate various observing characteristics at 20 cm. Is the "Centre frequency" specified in the calculator the actual centre frequency of the usable band (~1500 MHz) or is it the centre frequency used in the scheduler (1750 MHz)? I assume it is not the latter but just wanted to make sure.

Cheers,

Emil.

Re: ATCA Sensitivity Calculator

PostPosted: Tue May 04, 2010 12:10 pm
by ste616
Hi Emil,

I should also let you know that it is better to use the new version of the sensitivity calculator:

http://www.narrabri.atnf.csiro.au/cgi-b ... /atsen5.pl

It fixes a few bugs and has a nicer interface :)

To answer your question, you should put in the centre frequency used by the scheduler. The calculator determines the receiver by the centre frequency, and whenever it sees that L-band (or S-band for that matter) is being used, it simply takes the bandwidth known to be good for that receiver. So in effect, you could put any frequency lower than 2000 MHz as the centre frequency and get the same answer for L-band, or any frequency between 2000 and 3000 MHz and get the same answer for S-band.

If anyone has any questions about our calculator, or would like to get the source for the calculator, please let me know!

Re: ATCA Sensitivity Calculator

PostPosted: Tue May 04, 2010 12:27 pm
by len067
Hi Jamie,

Hmm, I'm glad I checked! ;-)

In your explanation above, where you say that anything <2 GHz should give the same result, are you referring to the new version of the sensitivity calculator (at the link you provided) or the current one? It just that in the current one using 1.75 GHz and 1.5 GHz result in different sensitivities (with all other inputs remaining the same).

I've give the new calculator a whirl and see how it goes.

Hmm, now that I tried, the new calculator does the same i.e. different results if I use 1.75 GHz instead of 1.5 GHz. :-(

Cheers,

Emil.

Re: ATCA Sensitivity Calculator

PostPosted: Tue May 04, 2010 12:42 pm
by ste616
Hi Emil,

Well that will need to be fixed.

In that case, the centre frequency that you specify will determine the system temperature that it uses, so you should choose the centre frequency that you're actually interested in, not the one that you're forced into having by the scheduler.

Re: ATCA Sensitivity Calculator

PostPosted: Tue Jul 19, 2011 5:04 pm
by ste616
The latest sensitivity calculator can be found at:

http://www.narrabri.atnf.csiro.au/cgi-b ... /atsen8.pl

It now has information for the wideband 16cm receivers, so you can enter different centre frequencies between 1.7 and 2.5 GHz and get reasonably sensible results. For reference though, the recommended centre frequency for 16cm is 2.1 GHz.

Re: ATCA Sensitivity Calculator

PostPosted: Tue Jul 19, 2011 5:24 pm
by len067
Hi Jamie,

Excellent!

BTW, is it worth listing the recommended central frequencies (at least for the centimetre wavelengths) or perhaps adding a link to a page where these are specified?

Cheers,

Emil.