[mmaimcal] Query from Jaap Baars

[Al Wootten]

I will place the memo received from Jaap on this at the WWW site for
tomorrow's meeting as soon as I get it out of Word into text.

Al

Dear Colleagues,

as a result of the last ALG meeting in Berkeley, I have been asked, 
and have begun, to consider the antennas for the Atacama Compact 
Array (ACA).

In developing first ideas about possible ways of approaching the 
design and procurement of the ACA antennas, I am naturally also 
considering using as much as possible in hardware from the ALMA 
production antennas.
However, clearly, the reflector with its quadripod and apex top 
section will have to be designed anew.

It occurs to me that an important design driver for these small 
antennas will be the possible incorporation of a nutating 
subreflector. If these are needed, it will have a major influence on 
the design, and the cost, of the antennas. From a design and cost 
perspective, we should avoid them, if at all permissible.

It is for this reason that I approach you, as Project Scientists and 
ASAC Chairmen, with the question:

Do any, or all, of the ACA antennas have to be equipped with a 
nutating subreflector?
Or can we do without them, and make life a lot easier and cheaper?

I shall be grateful for your views on this matter at your earliest convenience.

Thank you very much for your help,

best regards,

Jaap