Basic tuning procedures for Receiver W (B and D bands)

These instructions are not intended to provide a complete description; they are a prompt sheet to help after having done it a few times.

• A. In the control room...
• Submit the RxW MSB using the query and queue tool the normal way
• Wait for the tuning screen to appear and select the appopriate option -
• Tuning Complete - your are done! The observation can go ahead
• to Zenith + Tune - new frequency you need to tune
• to Zenith - already tuned but you need to lock the Gunn and/or check/optimize the tuning.
• Abort Obs
• Tune RxA3i to 221.3 LSB to avoid interference - or turn off RxA3i.
• B. In the cabin ... This is for a complete tuning - if optimizing /checking do only what is appropriate
• Check the receiver, esp. the electronics rack, for anomalous settings which may have been left after previous work.
• Select B or D band by rotating the LO injection grids as required
• Tune and lock the Gunn using the value you get when pressing the appropriate button on the RxW micro. Check the lock with the spectrum analyzer below RxA - and check to see that spectrum analyzer cable is connected to correct band monitor port on PLL.
• For D-band: tune the multiplier using the values supplied when pressing the appropriate button on the RxW micro. The tuning curves are not perfect. So if you see mixer current it is easier to maximize the current instead of just go to the supplied values. At least take note of the values where you saw current so you can go back
• Check for mixer current -
  • If no mixer current - set the modulator to 100% in manual mode.
  • If still no current go back and recheck B/D band, and Gunn & multipler tunings.
  
  
• If you selected to Zenith + tune you can now press remote on the micro to set the IF level and mixer currents automatically. Make sure the modulator control is in remote first. Optionally you can continue in manual mode but make sure you leave the modulator in computer mode when finished.
• With the mixer current at the nominal setting switch to the Trx meter and the load modules to manual.
• Optimize the Trx using the LO interferometers
• In DSB only - optimize the SSB interferometers
• In SSB do not tune the SSB interferometer very far away from starting position (and note down, or remember, your starting point)
• When finished make sure you set the modulator to computer control.
• If you selected Tune+Zenith press remote again
• B. In the control again...
• Select "Tuning Complete" in the manual tuning window. Oberving will start.
• Check for phase lock errors