User's Manual for B3 Remote Tuning Basics

B3 is designed for remote tuning from the TSS's command screen. Normally tuning will be done under computer control. It is extremely useful, though not essential to receiver operation, to have the status screen up and running.

A visual check of B3 in the cabin at the start of the night is useful. In particular ensure that all (five) pull toggle switches on the B3 auxiliary electronics rack in the receiver cabin are in the remote position. The software cannot take command of any component left in manual mode by these switches. The positions of other smaller toggle switches on the receiver are not important as they are overridden in remote control mode.

At the TO's console issue the following ICL commands:

1. ICL> fe]

   Respond appropriately to the prompts. You may choose to put the line frequency in either the USB or LSB, to observe in either DUAL or SINGLE polarization and in either SSB or DSB. The fe] command sets the receiver parameters to the values prescribed in the look-up tables (LUTs) stored under VMS.

   Upon termination of the fe procedure check that the B3 display screen is not showing any parameter values in reverse video. If, for some reason, the actual value of a parameter has not been set to the demand value, the actual value will be displayed in reverse video underneath the demand value.

   The current mixers are both tunerless, and are expected to remain that way. Because the backshort mechanisms are still in place, although not physically connected to the mixer blocks they are set to a nominal value of 20, independent of frequency.

2. ICL> be]

   Following the fe command it is necessary to set up and configure the DAS prior to calibrating. (Use backend CBE for pointing, and IFD for beam-mapping)

3. ICL> cal]

   Calibrate if using the DAS. If the results of the calibration are satisfactory, tuning is complete.