Sbh tsys polB high: dec19


    The sbh receiver warmed up on 04nov19. It was cooled back down on 26nov19. During this period there were changes in the measured Tsys.

    After the cooldown both TsysA and TsysB came back higher, then on 02dec19 polA jumped back down to its pre-warmup value.

The plots show sbh Tsys PolA, and PolB as well as TsysPolA-TsysPolB for 2019 (.ps) (.pdf)

SEFD shows real tsys problem.

    A change in Tsys could be a problem with the cals used to measure the Tsys, or a real problem with the system temperature.
The SEFD is the ratio of  Tsys/gain.   Since both of these measurements use the cal values, the ratio cancels out the cal usage. If the SEFD shows a change, it is not because of a problem with the cals values.
    On 07dec19 and x102 run tracked 3C48 with the sbh receiver.

The plots show the SEFD changing similar to the Tsys change (.ps) (.pdf)


processing: x101/191222/