Radar Setup Advice

Note: this page is very obsolete. Please use instead the following page:

New GBT Radar Observing Advice

Advice for setting up for planetary radar observing with the GBT.

Center Frequency of IF input of Radar Backend: 720 MHz
Converter module CM10, J4 connects to Radar PFS Input A.
Converter module CM14, J4 connects to Radar PFS Input B.
Set RF power in CM10&14 to about 0.5 v.
Setup scripts are in /home/astro-util/radar/
Standard S-band setup: radar_S.py
Standard X-band setup: radar_X.py
Standard P-band setup: pband_setup.py
Asteroid ephemeris tables: /home/gbt/etc/config/Asteroid.tbl
Select User Defined coordinates in GO when using Asteroid table.
Alternately, use a GO Table with rates. (see below)

Radar back end: PFS (portable fast sampler)

Developed at Arecibo, described here.

Example of Asteroid.tbl

	#
	#             UTC        RA___apparent___DEC  
	2002 08 18 16:00:00  11:49:29.63  +31:46:18.1
	2002 08 18 16:01:00  11:49:15.59  +31:44:23.8
	2002 08 18 16:02:00  11:49:01.59  +31:42:29.6
	2002 08 18 16:03:00  11:48:47.64  +31:40:35.6
	2002 08 18 16:04:00  11:48:33.72  +31:38:41.8
	2002 08 18 16:05:00  11:48:19.84  +31:36:48.1
	2002 08 18 16:06:00  11:48:06.01  +31:34:54.6

Note that one must select the Coordinate Mode in GO to match what is used in the table (ApparentRaDec in this case).

To activate a User Table:

Copy the table to /home/gbt/etc/config/Asteroid.tbl
In the main GO screen, under "coordinate selection", select "UserTbl" under the "New Origin" button.
In GO, make sure longitude, latitude, Long.Rate, Lat.Rate are all set to zero.
In GO, press the "Start" button to start the antenna following the table. If the table has more than a few hundred lines there will be a several second delay while GO converts the table to a list of instructions for the antenna manager.

Example of GO Table

#
header \
   sc.starttime   ra   dec   ra_rate   dec_rate   procedure
16:00:00  11:49:29.63  +31:46:18.1   -2.969   -1.900     track
16:05:00  11:48:19.84  +31:36:48.1   -2.931   -1.887     track
16:10:00  11:47:11.06  +31:27:22.0   -2.894   -1.874     track
16:15:00  11:46:03.26  +31:17:59.9   -2.857   -1.860     track
16:20:00  11:44:56.44  +31:08:41.8   -2.821   -1.847     track
16:25:00  11:43:50.57  +30:59:27.6   -2.786   -1.834     track
#

 NOTE: there must be no blank spaces following the backslash (\)
	in the "header" line !!!

Hardware notes

There are 2 computers in the radar data acquisition rack:

pfs1 and pfs2

The system needs NRAO-supplied reference signals:

A 10 MHz reference signal.
A 750 MHz LO signal.
A one PPS signal.
Sometimes a 20 MHz or 1 MHz signal is also required.

All the above signals must be locked to the H-maser.

Modified by F. Ghigo Feb 2005