[daip] ANTAB problem reading WX table with 2001 data.

[Eric Greisen]

On 07/28/2015 04:45 PM, Eric Greisen wrote:
> On 07/25/2015 11:45 PM, R. Craig Walker wrote:
>>
>> I tried running APCAL on 43 GHz VLBA data taken in 2001.  I was trying
>> to fit the opacity.  For every station, I got a message of the form:
>> APCAL1: REAWX: *** NO TEMPS FOUND IN WX TABLE FOR ANT 8, LEFT AT 0 ***
>> INVERS is set to 1 and there is a WX table with valid looking
>> temperatures for all antennas.  So something is wrong, presumably in
>> reading that table.

I found the problem in APCAL - it required the "I don't care" value for 
subarray to be 0 when <= 0 is correct and required.

No need to provide data.  MNJ tomorrow will fix.

>>
>> I compared the table to a modern one from data taken last year.  I see
>> a couple of differences, but I don't know if they will confuse the
>> reader.  The old table has 10 columns while the new one has 11.  The
>> missing one in the old table is the subarray (not sure why the weather
>> data should depend on subarray, but oh well).  The other difference is
>> the column heading for temperature.  The old file had "TEMPE" while
>> the new one has "TEMPERA".
>>
>> I plotted the data with WETHR, and that found the temperature data,
>> although it took some considerable staring at the help file to figure
>> out how to get it not to edit data.  I suggest a more obvious switch
>> than just OPTYPE='MULT'.  Using display programs that can alter your
>> data if you put in inappropriate parameters is always a bit scary to
>> me.  VPLOT is another example.

WETHR flags only when OPTYPE='FLAG' - how can we make that more 
obvious???  I admit that VPLOT is less obvious...

Eric


>>
>> WETHR worked and there are reasonable looking temperatures (~63
>> points) for most stations.  Unfortunately there are some suspicious
>> data where various parameters step a lot (eg pressure from 650 to 980
>> mbar at NL) That's in the WX table according to PRTAB, so it is not
>> WETHR's fault.  Sometimes I think I shouldn't look at my data!  The
>> issue is not there in the weather data plots from tsm (outside AIPS),
>> so it appears to be a calibration transfer issue.
>>
>> To salvage that, I ran VLOG and and tried using the resulting weather
>> file.  I see that there is a warning in the VLOG.HLP that the cal.vlba
>> file is based on the legacy system.  That will be changing in the
>> rather near future so we should remember to update the HLP file.
>>
>> VLOG worked, after some fumbling, and produced an external WX table.
>> APCAL is happy with that and does give answers that are somewhat
>> different from what it got guessing values when it couldn't use the WX
>> table.
>>
>> So the main thing I'm reporting here is that APCAL does not seem to be
>> able to read the old (2001) WX table even though PRTAB and WETHR can,
>> and APCAL can run properly with the same inputs when given an external
>> file.  If the cause is not obvious, I could produce a test file, but
>> the data are at home so that will take jumping through a few hoops.
>>
>
> I will need to see what happens  - the WXINI routine should complain if
> it does not find a column it expects.  And TABWX is very careful to
> honor whatever WXINI set up.
>
> Eric
>
>
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