[mmaimcal]Meeting

[Mark Holdaway]

On Wed, 11 Dec 2002, John Conway wrote:

> 
> Hi,
> 
> I guess I was thinking of having a whole cycle 
> longer than a year and less time in the extreme
> arrays giving a rate of one move day every four,
> but Mark is right one probably wants quite a 
> bit of time in the extreme arrays.
> 
>  Of the suggestions given I like Angels the best 
> Doing  an average rate of 12 moves  per week is certainly 
> feasible given the transporter capacity though it  
> means moving almost every second day which seems 
> just a litle high for sustained operations.
> I think there is an argument for going through 
> the arrays between the largest spiral and the extreme 
> Y+ faster than the rest.

I agree that there are such arguments, but will also point
out that these arguments have already been factored into the
array design, as the resolution will be increasing with reconfiguration
of 4 antennas by a multiplicative factor more than twice as large as
the resolution increase factor for arrays smaller than 4 km.

I can accept this suggestion at this time, with the provision that
this is all flexible in responce to proposal pressure.

> If in the move out from most compact to largest spiral 
> we make moves on 1 day  out of every  3, then with 2moves/day/transporter
> and 2 transporters there are an average fo 1.33
> antenna moves/day. It take 108 moves hence 81 days (11.5 
> weeks) to go from compact to largest spiral.
> Moving from largest spiral to largest  Y+ if there are 42 pads 
> and we make moves on 2 days out of every 3 it 
> takes 16 days (2.3 weeks).
> 
> Assuming 6 weeks stopped in the extreme arrays the cycle time
> becomes 
> 
>  Compact              42 days
>  Compact -max spiral  81 days 
>  Max spiral - max Y+  16 days
>  max Y+               42 days
>  Max Y+ - max spiral  16 days
>  max spiral -compact  81 days
>                       ----
>                       278 days (39.7 weeks)

I will take this is my straw-plan for the moment.

> Note I make that 9 months equals 39 weeks 
> (not 36  as stated below)
> 
> 1) It might be thought that the time to 
> 'cycle the seasons' for the compact array 
> is  4 years in this scheme,  but remember
> you have a compact array every 9 months 
> ( incidently a a lot better than the VLA at one 
> every 16  months), so I think the time between when 
> the starting date of say the compact array 
> starts on 1 Jan and when it starts again on 
> 1 Jan is 3 years not 4, see the schedule below.

If the cycle is (1-1/n) years, it makes n cycles in n-1 years.
If the cycle is (1+1/n) years, it makes n cycles in n+1 years.

> 3) I'm not sure  a rational mumber for the 
> ratio of cycle time to year is needed, perhaps
> a cycle time of 40 or 41 weeks is as good
> or better that 39  days (9 Months).

Yes, as long as the seasons change.

> 4) Are there times of year we definitely 
> DON'T want to be in the compact or extreme 
> arrays (the Bolivian winter pehaps) we can schedule 
> one of the intermediate arrays for this (since they 
> occur every 4.5 months anyways its not too much loss).
> If we work such factors in this would argue for 
> a rational fraction between  cycle time and 1 year 
> and for a particular phasing of that cycle.

My opinion: all configurations need to share in the Bolivian
winter, just as all configurations should share in the good times
(at this point, you should picture an array of antennas drinking
vodka and dancing -- don't ask me, I dislike vodka myself).

Once I get a scheme for the reconfiguration cycle that we
are all OK with (a hope), I will manufacture a complete
dataset of TAU and RMS_PHASE (by filling in the gaps in
the site testing data by hook or by crook), turn the crank
to reconfigure for about 3 years, and then look at the
distributions in TAU and PHASE for each configuration
and each LST range, basically to verify that EACH
source and EACH configuration is getting a fair shake.

Meanwhile, i need to stop doing this and get back to other work!

  -M