[evlatests] Antenna 16 Q-band total power

[Jim Ulvestad]

Remember, there hasn't been a run of holography and
panel-resetting since the Q band feeds were moved.
There were some strong hints that the panel re-setting
was partially taking out subreflector irregularities, so
we should expect the aperture efficiency to go down
compared to the previous feed location.  I suspect that
different antennas had different fractions of error due to
the panel setting and the subreflector, so it may be hard
to predict how much we might have lost.

Jim

Bryan Butler wrote:

>
>
> On 12/8/05 16:17, Walter Brisken wrote:
>
>> At peak, the total power detector reported -28.63dB.  Comparing to 
>> the off-source value of -29.69dB suggests that Venus added 27% to 
>> Tsys.  This offset explains Ken's non-fringes.  Is anyone prepared to 
>> say if this is reasonable?
>
>
> i can comment on the Tsys value.  expected increase in Tsys from venus 
> at 43 GHz is ~40 K (assuming 35% efficiency).  if this added 27% to 
> Tsys, then without venus Tsys was ~150 K, which is pretty high for 
> Q-band.  so either Tsys looks high, or the efficiency is much lower 
> than 35%.
>
>     -bryan
>
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