[asac] Re: ALMA rx specs (draft version) (fwd)

[Christine Wilson]

Hi, everyone,

I was wondering if we should plan to discuss the receiver specifications 
and the questions raised by Stephane Guilloteau at our next telecon? I 
sent a couple of comments in today, which I've copied to you all below.

Chris

---------- Forwarded message ----------
Date: Tue, 13 Jun 2000 16:58:53 -0400 (EDT)
From: Christine Wilson <wilson at physics.mcmaster.ca>
To: Wolfgang Wild <wild at astro.rug.nl>, jpayne at nrao.edu
Cc: Christine Wilson <wilson at physics.mcmaster.ca>
Subject: Re: ALMA rx specs (draft version)

Dear Wolfgang and John,

I'm sorry to be sending you this comment late, but I thought the ASAC 
might discuss your memo in our telecon yesterday.

One thing I was a little concerned about in your draft specs was the 4 
GHz IF bandwidth as a fallback position for the initial bands. Is the 
intention to have this a temporary situation i.e. would the receivers be 
upgradeable to 8 GHz bandwidth, or if we did have to go to this fallback 
position, would the initial receivers be permanently at the lower 
bandwidth?

Reducing the bandwidth has a significant impact on the continuum 
sensitivity of the array and on the ability of the array to do redshift 
searches, among other things.

The other point I noted was that selecting and tuning a new band should 
indeed be as fast as possible. Since many observations with ALMA might be 
of quite short duration, 15 minutes tuning time could produce a lot of 
overhead and/or more demands on the dynamic scheduler to schedule "like" 
projects in sequence.

Thanks,
Chris Wilson