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Setting up the Chart Recorder


  1. Check the levels on the meter on the front of the filter bank you are using. You should use the variable attenuators to set these 1/10 of a full scale deflection.
  2. Call the controller on the intercom by dialing 19, or on the phone by dialing 249.
  3. Ask the controller to drive to a bright source such as 3C274, 3C405 or 3C461. You can get a list of calibrator sources by typing psrcal 1 on arthur and entering a parameter file eg 600timing. The list is also shown in Section 6.
  4. Adjust the gain on the chart recorder so that the pens come about 2/3 of the way across when on source and then sit near the zero line when you unplug the IF inputs.
  5. Then, with the inputs unplugged, adjust the zero levels so that the pens sit on one of the dark lines on the paper - it is useful to offset the 2 pens by an inch or so.
  6. Check the levels when you plug the inputs back in and iterate the last 2 steps if necessary.
  7. Flick the cal on and off and check that you can see it clearly on the pen chart.
  8. Remove a db of attenuation to compare the marks on the chart recorder with those made by the cal to check that the cal is a suitable level. We usually use 0.6-0.8 of a db.

Jon Bell
Sun Aug 17 17:32:08 BST 1997