[evlatests] Ea19, at L-band

[Wes Grammer]

This receiver is modified for solar Tcals, so the noise cal input level 
is adjustable. If you are seeing the same issue on both RCP and LCP, 
there could be a problem with the digital attenuator(s) in the cal 
signal path, or the Cal board driving them.

Rick, I'll go in and re-send the default values now, and you can check 
whether the problem persists.

-Wes

On 8/15/2014 4:22 PM, Rick Perley wrote:
> Something is odd with ea19 at L-band.
>
>     The system temperature, as measured by the PSum/PDif ratio claims 
> to be about 150 K on 3C48.  However, the Tsys ratio between Cygnus A 
> and 3C48 is completely normal (4.82), so the sensitivity of the 
> antenna is fine -- these Tsys values are bogus.
>
>     This normally points to a bad value of Tcal.  But the value in the 
> 'CD' table is also completely normal -- 1.42K.
>
>      So it's acting as if only about 1/4 of the switched noise power 
> is actually getting into the signal path.  (And indeed, the PDif 
> values are ~ 17 millicounts -- at least a factor of four too low). In 
> other words, the effective Tcal is about 0.35 K.
>
>     Can anybody explain what is wrong?
>
>
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