[evlatests] Ka-band tests, 33160 MHz

[Rick Perley]

    On Monday, Bob and I (aided by Brigette, Emmanuel and Gordon) 
continued Ka-band antenna tests. 

    Here I give the newer results for 33160 MHz, using the 'direct' path.

    Tr = 24.8
    Tcal = 5.30 (and is exactly the same on hot, cold, and sky -- 
proving the system is very linear)
    Tatm (at zenith) = 6.8  (Bryan says this is about right for the 
super-dry weather we had). 
    Tspill (zenith) = 25.4
    Tsys (zenith) = 57.0

    We got good rasters on 3C273, but the off-source baseline is 
slightly uncertain.  Assuming Craig's VLBA result of 24 Jy at 33 GHz is 
correct, we find

    effic. = 42%. 

    If the flux is 20 Jy (as I assumed before), effic = 50% (which would 
be too good for even me to believe). 

    The efficiency is slightly lower, and the spillover temperature 
somewhat higher than we expect.  There is likely a common cause. 

    I'll report the results from other frequencies (33144 MHz in the 
'indirect' path, and 39600 MHz, tomorrow).