lbw polB cal jump on 23apr04


     The system temperature for lbw jumped in 23apr04. At 2am polA, polB were the same. At 18:30 the temperatures were different by 20 percent. on off position switching was done on two unpolarized continuum source.  If the jump was in Tsys (the cals were ok) then the source deflection in kelvins should have been the same for polA and polB. If the jump was a change in the cal value, the the source deflections for the two sources should differ in polA and polB.
    The source were 3C232 and 4C32. The measurements used 1415 and 1665 Mhz with the feeds native linear mode.  The source fluxes are:
src flux (mJy)
flux (mJy)
3C232 1247 .72
4C32 1263 11.7

    There were 10 measurements of the two sources. 4 on 23apr04 evening and 6 more on 24apr04 evening. The plot shows the results (ps)   (pdf)

* 1415 Mhz
+ 1665 Mhz
Black TsysB/TsysA 3C232
Red TsysB/TsysA 4C32
Green TsrcB/TsrcA 3C232
Blue TsrcB/TsrcA 4C32


processing: x101/lb/