Quickdata Quikstop-15 Especificações descarregar pdf (Página 49)

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6.8. Unable to bring GTP’s down/up into normal range

Under some circumstances (usually weather inflicted), it is possible that you are

unable to use “matten au” in MOPS to bring the gated total powers into the

appropriate range. In these cases you always first try to tame the powers with the

MOPS attenuators: MOPS only automatically sets attenuators in the range of 0 to

12. Any higher attenuation (up to 15 is available) must be set manually.

To set them manually, use this command in MOPS (example to set all IF’s in Pol

A to 15):

matten a 15 15 15 15

Repeat for Polarisation B and use different attenuator values as needed.

If that still does not produce enough attenuation (or if you are already at a

marginally low power with attenuators set to 0), you can change the upstairs

attenuators (B6).

Here’s how to do it properly:

1. Check the B6 attenuator settings in the TOAD SYNOP window while

observing your science target. Take note of what the numbers are at

your observing frequency of interest.

2. Note: The attenuators change completely depending on what frequency

you are observing at, so you cannot make a guess while pointing at 86

GHz for what the attenuators will be at your observing frequency of 111

GHz!

3. Open a bigrock terminal (blue) and prepare the following command (do

not press enter yet):

4. atds control -a 27 -d 0xa9 -f 0x100 -h mpacc -p 8019

5. The 0xa9 part defines the attenuator values for Pol B and Pol A (in that

order) in hexadecimal format. You need to replace those with the values

you want. In this example, the numbers would set Polarisation B to 10 (‘A’

in hexadecimal) and Polarisation A to 9 (same in hexadecimal).

6. Start the schedule on your science target.

7. Run the above command and make sure your GTP’s are within range.

8. Stop and restart, a few seconds after you’ve started the schedule, run the

atds command again.

Note that this atds command must be repeated after every start of a

schedule because TCS resets the B6 after every start!

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Quickdata Quikstop-15 Especificações Página 49