ASSISTANCE will report errors if the power levels into the samplers are such that the samplers are unable to optimally sample the data - this is achieved when the sampler stats are 17.3%.
This can be because of hardware failure, however, often the problem is that the attenuators have not been set up correctly. Check the CAMON /stats and /samp pages and look at sampler levels and settings.
If all values are 0 or close to it, you probably have a hardware problem and need to call an expert.
If the sampler statistics are not approximately 17%, you should adjust the attenuators manually:
| Track strong source. | Usually your secondary calibrator | |||
CAOBS disable auto |
To turn off automatic attenuator setting. |
Bad sampler values will be highlighted on the CAMON /samp
page. To adjust the fine attenuators on antenna ca0n for feeds
A1, B1, A2, B2 (i.e., X and Y on frequency 1, and X and Y on frequency 2)
use:
| CAOBS set atten ca0n jklm |
Only change the values for the feeds that need adjusting. The fine attenuator settings j, k, l and m can range from 0 to 7. |
If you only wish to change the attenuation of frequency 1 feeds, then
omit lm. Likewise to only change those for frequency 2, use:
CAOBS set atten ca0n *lm
For more information see
which way to adjust the attenuator settings
.
If you need to adjust the settings beyond the range of the fine attenuators,
then you will need to adjust the coarse attenuation.
To show the current coarse attenuation:
| CAOBS show coarse |
Current setting will appear in the CAOBS window. | |||
| To adjust the coarse attenuation use: | ||||
| CAOBS set coarse ca0n jklm |
Where the coarse attenuator settings range from 0 to 3. |
After the attenuation has settled down again, enable automatic attenuation
mode with:
CAOBS enable auto
If you are still having problems obtaining appropriate attenuation, then it
is likely to be a bigger problem - seek help from your DA. The CAMON pages
/fe1, /fe2, /cr are useful to investigate more insidious receiver
problems.