TotPwr images of a2010 apr05 data showing radar with
A2010 is doing 600 second drift scans with
alfa (each 600 second drift is refered to as a strip). The center frequency
is 1385 with 100 Mhz bandwidth and 1 second 3 level sampling. For each
strip the total power was computed for each beam/pol after removing frequency
channels with rfi. The data was then normalized to the median value for
each strip. Images were made of this value with strip number vs sample.
Alfa has problems with saturation from the 1350
Mhz radar. Occasionally the power will increase and then take 10 to 20
seconds to recover. On 05apr05 a 10 db amplifier was placed before the
1st mixer upstairs to test the oh path (with the new filterbank). This
amplifier improves Tsys (at least for polB at HI). We need to know if it
is making the saturation problem worse.
The images below show the total power for a strip
versus strip number. The top plot on each page is polA and the bottom plot
is polB. The data is taken from 02apr05 thru 07apr05. At strip number
150 (the dashed line in the image) the amplifier was installed in pixel2a,b.
The closely spaced dots are the radar compression. The longer lines are
continuum sources drifting through the beam. Radar problems occurred:
They appeared more often in pixel 2a,b after strip 150 (when the new amp
strips 1-30. Pix0B pix2B, pix3a,
strips > 150. pix2a,2b,