Running the Fringe Checker
Once all the RtFC processes are running and the disks are recording,
you are ready to fringe test. It is recommended you first check
the
sampler statistics of the data looking at the cdisko monitoring. If you
are
using a config file for ui.pl, you should make sure the values are
sensible before you start ui.pl. All fringe testing is run from ui.pl.
As this is an interactive program there are many ways to run this. The
following is a guide.
Check which observatories are connected:
>
obs
Disable Parkes because it is not tracking yet, and Ceduna as we will do
it later once we know we have fringes to other telescopes
>
disable Cd
> disable Pa
Check the integration time we are using then set to a sensible value:
>
int
> int 0.1
Set the number of frequency points to create (note incorrect term)
> nchan 512
Start a fringe check running for the specified UT time
>
grab 03:45:34
The data will be copied to Parkes, the data passed to the software
correlator and the result plotted using pgplot and put on the web
at http://www.evlbi.atnf.csiro.au/RtFC (pkpam, if at Parkes).
There is a bit of a delay offset to Mopra. Correct for this and
recorrelate the data to ATCA only
>
offset Mp 3.4
> obs
> disable Pa Ho Cd
> recorr 03:34:34
This will use the data already on disk and recalculate the
correlation
using a different clock offset.
Once you have the good clock offsets, its is worth adding them to your
"config" file.
Get some Ceduna data now. To save time, change the integration time
to 250 msec. Grab a time 1 second before or after a sucessfull
correlation
>
obs
> enable Cd
> int 0.25
> grab 03:34:35
Remember to set the integration time etc back
>
int 0.5
> disable Cd
If you get impatient due to a slow download, you can "recorr" before
the data has arrived. The correlator will correlate up to the length of
the end of the smallest data file.
If
a station has a suspected 1 second (or more) offset the "offset"
command is not suitable. Use secoffset. You have to "regrab" the
data after changing secoffset
>
secoffset Mp 1
> grab 03:35:99