Configuring the NEXRAD Decoder

If you will be decoding radar (formerly NEXRAD; now WSR-88D and TDWR) products you must configure the file NEXRID.CFG (which defines the stations and products that will be decoded by the NEXRFILE decoder, and the amount and location of data to store) and then activate the data monitor.

Edit the file ~oper/mcidas/data/NEXRID.CFG and set the values for the following variables:

FILE= and EXCEPT= variables in the STATIONS control line
FILE= and EXCEPT= variables in the PRODUCTS control line
WSRFILE=, TDWRFILE=and KEEP= variables in the DISPOSE control line

Activate the NEXRAD data monitor by running the following command in a McIDAS-X session running under the oper account.

Type: DECINFO SET DMNEXR ACTIVE

Note: The Unix warning message component of path does not exist will normally be displayed by the NEXRAD decoder each time it creates a subdirectory for incoming stations and products. The error message is normal, so can be ignored.

Creating a Separate Spool File for the NEXRAD Decoder (optional)

This procedure is optional and is available only to sites that receive data via the LDM. The procedure significantly reduces processor usage by creating a separate spool file for NEXRAD data. The gains in efficiency are due to the NEXRAD decoder no longer needing to scan through GRIB data looking for the next NEXRAD product and vice-versa for the GRIB decoder.

Complete the steps below to implement the procedure.

Run the command below from the McIDAS-X Text and Command window to stop the NEXRAD decoder.

Type: DECINFO SET DMNEXR INACTIVE

Run the command below from the Unix prompt to copy the NBIN circuit configuration file (no changes to the file need be made).

Type: cp ~oper/mcidas/data/NBIN.CFG ~oper/mcidas/data/NEXR.CFG

Run the command below from the McIDAS-X Text and Command window to add the new NEXR circuit.

Type: CIRCUIT ADD NEXR INGESTOR=INGEBIN CONFIG=NEXR.CFG SPOOL=NEXR.SPL "NOAAPORT NWSTG NEXRAD Binary Circuit

Modify the NEXRAD decoder configuration file with the name of the new circuit.

Open the file ~oper/mcidas/data/NEXRFILE.CFG for editing.
Change the value of SPLFILE= to NEXR.SPL.
Save and close the file.

Run the command below from the McIDAS-X Text and Command window to define the full Unix path of the NEXR.SPL file.

Type: REDIRECT ADD NEXR.SPL "/data_directory_path

For example: REDIRECT ADD NEXR.SPL "/home/oper/xcd_data

Modify the LDM configuration so that it pipes NEXRAD data to a second instance of the binary ingestor.

Open the file ~ldm/etc/pqact.conf for editing.
Create a separate entry in the Request Entries section for NEXRAD data and set it to pipe the data to the binary ingestor using the NEXR circuit. If you had a line that contained NNEXRAD as well as other binary feeds such as HRS, remove NNEXRAD from this line. The resulting entry should look like that in the box below.
NNEXRAD ^.* PIPE /home/oper/mcidas/bin/ingebin.k NEXR
Save and close the file.

Run the command below from the Unix prompt to remove the old pointer file for the NEXRAD decoder.

Type: rm ~oper/mcidas/data/NEXRFILE.PRO

Run the command below from the Unix prompt to stop and restart the LDM.

Type: ldmadmin restart

Run the command below from the McIDAS-X Text and Command window to start the NEXRAD decoder.

Type: DECINFO SET DMNEXR ACTIVE

You should notice very soon after starting the NEXRAD decoder that there is a third entry in the ingestor section of the statdisp display. Two instances of the binary ingestor (INGEBIN) will exist. The NEXRAD data should now be written to NEXR.SPL by the binary ingestor using the NEXR circuit.