12m position switching with winking cal

Processing the data
Plotting the results


      Experiments are being performed to see if we can monitor variable sources who have flux levels on the order of Janskies. The current sefd of the 12meter is about  4000 Jy (so this is going to be tough :). The new cooled wide band receiver will help since it's expected system temperature will improve by a factor of 2 or 3.
    The current variable source tests are using:

    If we used on,off position switching then the on source integration time could be about 50%. Possible trouble with on.off position switching are:

Problems with the current warm receiver:

    We've seen that the current  12meter (warm receiver) output level changes with temperature.

    Since the cal diode is temperature stabilized, the 25Hz hardware winking cal  can be used to correct for the electronic gain variations with temperature.

The ra,dec mapping tests are using the hardware winking cal. The crosses are not using the winking cal.

Look at on,off position switching stability using the hardware winking.

   Some tests were run using  on,off position switching with the  hardware winking cal running during the on and off position. We wanted to see
if it was an acceptable alternative to the  radec mapping or cross patterns when monitoring total power from weak sources. It will also give us some insights into how good (or bad) the current warm receiver is. 


Processing the data:

Plotting the results:

    There are two sets of plots:

Notes on plots
processing: x101/220803/onoffwcal.pro, 220819/onoffwcal.pro.pro


12meter page