[asac] comments on report

[Christine Wilson]

Hi, Jack,

Here are my comments on the draft of the ASAC report. I've put the 
substantial ones at the top and the typos etc. at the end.

Chris

MAJOR COMMENTS

As I mentioned in the telecon, I'm worried that the momentum is building 
quickly towards a project with a 20% cut to the contributions of North 
America and Europe. I think it's important that our report comes out 
strongly and clearly against such a cut. One way to do this would be to 
have a section in the report where we collect together all the issues 
regarding the 20% cut; at the moment they are in various places 
throughout the report. Although this might paraphrase our letter to the 
ACC somewhat, I think it's important that our report (which will 
eventually be public) spells the issues out.

In the last sentence of the section on management structure, you might 
check with people like Bob Brown and so on that it is OK to say that we 
intend to have a continuing upgrades budget. I got the impression at
the meeting that this money WAS proposed in the NSF budget, but was sort 
of hidden as operations and not identified as upgrades. We should 
certainly talk about the scientific NEED for such funds, and that is done 
later in the document.

The whole second paragraph of the configurations section was not 
discussed at the ASAC meeting, because the PDR had yet to take place. I 
think we should remove this section from our report and put it in the 
minutes of today's telecon.

In the section on Frequency Bands, unless our letter to the ACC is going 
to be made public by posting on the web page, we should make sure the 
essential contents are included in our report.

On page 4, we talk about possibly postponing Band 10 and bringing up one 
of the other bands instead. I'm not sure we want to say this, it seems a 
bit dangerous to talk about substituting one band for another. I think 
that sentence could just be removed.

In the section on Total Power Stability, it might make sense to add the 
polarization justification here (from page 13). Similarly, we might want 
to move the section on page 5 on Calibration Accuracy to the section on 
Calibration (on page 15). (Calibration is not only fragmente in the 
project, it's fragmented in our report!)

On page 8, maybe I'm just still confused about the correlators, but I have a
question. Does the reprogramming of the baseline correlator give you the same
total efficiency as the Future or Enhanced correlator, albeit with many fewer
channels and some restriction on total bandwidth? If so, it would be nice to
say so CLEARLY in our report. 

Still on page 8, if we expect the correlator plans and costs by only 
September 2002, then we ought to specify frequent reports as to their 
progress. I see this situation as rather like the configuration issue; we 
start off with two competing designs and, if we're lucky, they will 
converge to something better than either initial design.

In the polarization section on page 12, I think it's important to explore 
the issue of rotating some receivers by 45 degrees a little bit more. In 
particular, the Receiver group could be asked to see whether band 7 could 
be rotated without impacting the optics etc. Someone else could look into 
whether the 45 degree phase rotator would in fact be inexpensive and 
low-noise. Perhaps this is something for the polarimetry group (when it 
is set up) to focus on.


MINOR COMMENTS/TYPOS

- the report should list the members (present and absent) and other 
people who were present

- in the Status report section: "major design AND development activities 
in Japan."

- the formatting is rather incoherent at the moment; some parts are 
sectioned and others not.

- in "Towards 3-way partnership": "The issue of the 20% CUT was discussed 
..."; also I would remove "the" in front of ALMA in that paragraph.

- in "Configurations", first sentences has "the the"; later down that 
paragraph, "The committee WAS very impressed ..."

- I think the first paragraph on the correlators has too much detail

- you have % that are mis-TeXed on: page 7, second paragraph; two in page 
13, first paragraph

- I would prefer not to refer to web pages, which may change or 
disappear, in our report. On page 7, instead of refering to the Table, 
perhaps we could give a couple of examples of how tradeoff in capacity 
for efficiency works; similarly, if the report on the Japanese FX design 
is available in the memo series, we should refer to it there.

- pg 8, I would substitute "considered" or "compared" for "pondered"

-pg 11, remove "the" in front of ALMA

- pg 11, what does "a phase-difference measurement" mean?

- pg 12, I wouldn't discuss the widgets, since we're not considering it.