[daip] FRING "feature"

[Jim Ulvestad]

{ ... forwarded by Katherine Blundell]

>>>>> "LC" == Litsa Close <litsa.close at magdalen.oxford.ac.uk> writes:

LC> Hi, i was just wondering if you could ask someone in Socorro
LC> (which I was told is where you are) about the error message I get
LC> when I run FRING on my VLBI stuff. I've been talking to Robert
LC> about it and he doesn't really know. basically, it says:
LC> 'Frequencies do not lie on a uniform grid. This may degrade the
LC> determination of delays'. This seems to be a feature of the whole
LC> data set. Robert thinks it might have some thing to do with what
LC> the task TAMRG did to my data. I ran this straight after FITLD and
LC> before I separated out the 90 and 50 cm stuff. It would be great
LC> if you could ask someone about this and let me know if you get
LC> some ideas about what could be wrong.  Thanks, Litsa

Hi Litsa,  I also have been getting this error message in some
circumstances, but haven't seen any evidence that it is doing
anything bad to my data.  I also haven't tried to isolate it in
order to determine what the precise cause is.  TAMRG sounds like
a reasonable guess, since I have only been getting this message
for the last year or so, namely after we turned on calibration
transfer and had to start running it.

We will look into this and get back to you if/when we can provide
a more definitive response, because this message is probably 
occurring for a lot of people, and most of us have just chosen
to ignore it!  (Not a wise move, but it happens ...)

It may be that we will ask you for a copy of your data set, or
part of the data set, so that we can try to reproduce the
error, but I'll wait to see if anyone else knows the answer
first.  Can you send a copy of your FRING inputs to daip at aoc.nrao.edu
so that we can check to see if one of the input parameters is
doin this to you?

Best,

Jim Ulvestad