From: <Tasso.Tzioumis_at_email.protected>
Date: Fri, 13 Apr 2007 00:32:40 +1000

Steven mate,

Thanks for the opportunity to comment on this. Unfortunately I missed
most of the science workshop due to other commitments and did not
have a chance to contribute to this. So here are a few comments:

1. The question of MIRANDA configurations and field-of-view questions
are covered extensively in the text but not in your introduction/
summary up-front. I think it will be good to mention this there for
those who do not read the details. From the introduction I've got the
impression that this was a huge and unsolvable limitation, where in
the later text the discussion is much better balanced.

2. In the evlbi section you need to mention U. Tas. explicitly as an
equal partner. It is probably an oversight from an earlier version
without Hobart.

3. In the introduction, L-band in Ceduna is mentioned. It may be
cheaper to do but I cannot see where the funds will come from, so I
do not think it'll ever happen.

4. And this brings me to the main point, about 2.4 GHz capability on
MIRANDA:
I was not in the discussions but I think we are giving up on that too
early and too easily. I think there are many reasons to have 2.4 GHz,
at least on bits of MIRANDA.
On uv-considerations we have:
- Ceduna is the obvious one (and I do not think L-band will happen
there unless we can find some new source of funding).
- there are also the AuScope antennas, especially Katherine, that
will fill in the uv very well
- the NZ antennas which will provide 6000km baselines to MIRANDA,
doubling the resolution
- filling in the uv gap to South Africa. The 9000km baselines will
now reduce to 6000km baselines. And if the in-between spacings are
filled by NZ, then the uv would be phenomenal.
- other tracking antennas e.g. New Norcia and the APT antennas in
Japan and China.
With all those antennas, then MIRANDA may look more like an SKA
pathfinder...
So, I think 2.4 GHz opens up huge possibilities for VLBI and even eVLBI.

Even if only a subset of the MIRANDA antennas are fitted with the S-
band receivers, the gains will be very large.

Then are other possibilities like tracking spacecraft as we did with
Huygens. Again, a big equivalent antenna in WA will complement our
other antennas in the East coast by providing both uv and time coverage.

I think the impact on VLBI and the science we do with it will be
large if MIRANDA was extended to 2.4 GHz and the possibility is not
even seriously addressed here. I feel we need to make the case as
strongly as we can, even if it appears that it is not possible under
the current MIRANDA parameters.

Cheers for now
Tasso
Received on 2007-04-13 00:33:01