TGBT14A_912_79 - Bank to bank variations with noise source

Goals

• test banks E through H with a new, flat-bandpass, noise source.

Details

• set up the new noise source, through the attenuator, through an 8-way splitter, to VEGAS Banks E-H
• Start with VEGAS in mode 4, then switch to mode 1
• John puts in a 300 MHz, low pass filter
• Configure bank_gain_mode4_cband_nocal
• setValues 2**27.5
• attenuator setting 4dB
• Scan 1 - 10 secs
• att setting 5dB
• Scan 2 - 10 secs
• form ratio Scan 1 / Scan 2 for all four banks (pol 0). Results look extremely similar from bank to bank
• remove low pass filter, need to set att to 7 dB to get back to -20dBm
• filtersnap now around -23dBm - SetValues 2**28
• Scan 3 - 10 secs
• set attenuator to 8dB
• Scan 4 - 10 secs
• form ratio Scan 3 / Scan 4. Again, results look extremely similar.
• Connect the noise source to the inputs of the VEGAS IF module. Need to remove amplifier, set attenuator to 20dB
• SetValues 2**27
• Scan 5 - 10 secs
• Set attenuator to 21dB
• Scan 6 - 10 secs
• Set attenuator to 25dB
• Scan 7 - 10 secs
• set attenuator to 15 dB
• Scan 8 - 10 secs
• have to stop at this point

• reconfigure to normal.
• Bank H now seems to have too much gain in the Converter Rack! Put the 10dB pad back onto the input to VEGAS