[mmaimcal]Meeting

[John Conway]

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.

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)

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.

 1 Jan 2010
 1 Oct 2010
 1 July 2011
 1 April 2012
 1 Jan 2013 

Put another way it in fact takes 18 months not two 
years to switch to the opposite season.

2) In a Zig-Zag reconfiguration cycle scheme 
as opposed to the sawtooth of the VLA the 
'time to cycle' the seasons depend on which 
configuration you are in. Its longest for the 
extreme arrays (compact and extreme Y+). For 
the intermediate arrays it will be 4.5 months 
between when such configurations repeat not 9 
months. I havn't worked out the time to 
'Cycle the seasons' for these intermediates.

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).

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.


   John

 





On Tue, 10 Dec 2002, Angel Otarola wrote:

> 
> Hi Mark,
> Another idea:
> 4 moves/day, 3 times per week (Monday, Thursday, Saturday for example)
> Also assuming 6 weeks for compact and y+ configurations per cycle, we then 
> get to the following situation:
> 
> Compact (N-S sub-configuration included)         6 weeks
> March OUT                                       12 weeks
> Y+ Configuration                                  6 weeks
> March IN                                         12 weeks
> ------------
> Total: 36 weeks (9 months).
> 
> So in principle you will shift 1 season (quarter of the year) per year. In 
> this case Compact and Y+ configurations will shift to the opposite seasons 
> every two years. Sound this right?
> 
> Cheers,
> Angel
> 
> 
>