[daip] VLANT

[Eric Greisen]

Lynn D. Matthews wrote:
>> I have looked at the data files that apply to your run.  For the first 
>> (April 1) data set there are in fact no antennas that need correction. 
>> For the last one, antenna 21 has a correction entered May 16.  After 
>> that many antennas were moved to A array.  More antennas were moved in 
>> November and had corrections.  So in early November, you would have 
>> found a number of antennas not crossed off the future changes possible 
>> list that were crossed off by the end of November 2007.  There are 3 
>> however - 6, 9, 10 - which still have not appeared in the correction 
>> file and so VLANT is still looking for them to be at the stations you 
>> used.
>>
> 
> Antennas 6, 9, and 10 were the ones that VLANT corrected when I ran the 
> program on the May data back in Oct. 2007. Maybe I'm misunderstanding, 
> but does this mean that these corrections were somehow subsequently 
> "lost" from the correction file?

6,9,10 are the unmoving antennas (at present) and there are now no 
corrections for them in the 2007 or 2008 files.  When we switched from 
the ModComps to the current on-line system - right after your run - 
there was much confusion on such issues as the clock, the direction of 
North, etc.  I think the coordinates file was messed up for a short 
period of time until we discovered that the atmospheric phase 
contribution was not being applied on-line (to evla only??) and other 
nasty things.  Fortunately your data are for before the chaos but there 
may be confusion about baseline corrections after then.  I think we are 
in a better situation now - I would trust now not then.

Eric Greisen