Setting IF Levels

  The IF levels on the bar graphs in IF2 unit should be set correctly, and so the attenuator switches need not be adjusted. With 4 GHz IF receivers (currently only RxC2), the IF switch internally sets up the correct power levels every time a CAL is done. At the end of each sample observation, the Total Power levels are displayed (one pair for each cycle of a pssw observation, two pairs for bmsw). The mean value of these during a sample on the sky should be somewhere between approximately 3.0 and 8.0; if any of them are above 11.0 or below 1.0, the IF level settings should be checked accordingly, and the CAL and SAMple should be redone. Note that if at any time the IF level is changed, the CAL must be redone.

The DAS can now type out the normalized total power readings of the SKY, HOT and COLD after each CAL if the PRINT_POWER parameter is set to true. The default for this parameter is false to prevent extra lines being sent to the operator's terminal if the information is not desired.

To turn the option on:

ICL> send das set print_power true

and to turn it off again:

ICL> send das set print_power false