[evlatests] P-Band Status

[Walter Brisken]

I've been meaning to address the 11D and 24A IFs at P-band as per Steve's 
comments last week, but in the last week I haven't been able to coordinate 
it.  Today I tried a little but power was bouncing around too much to make 
any reliable adjustments (RFI?)  From below, it sounds like 24A is not a 
problem and 11 has problems on all IFs.  Determining proper attenuator 
values will have to wait until I return on Sunday or until someone else 
gets to it.

-W


On Mon, 26 Nov 2007, Rick Perley wrote:

>    I looked at P-band status at noon today:
>
>    Antennas 1 and 4 are out of the array.
>
>    Antenna 2 was stowed for servo work -- no data.
>
>    Antenna 16 has no receiver -- no data.
>
>    Of the remaining antennas, which were pointing, and are claimed to
> be outfitted:
>
>    a) Antenna 13 is claimed to be outfitted at P-band, but provides no
> fringes at all.  Its Tsys values are also completely corrupted.
>
>    b) Antenna 21's fringes are low by at least an order of magnitude on
> all IFs.  Tsys is shown as relatively normal, so the problem is in the
> signal path.
>
>    c) Antenna 11's fringes are low by a factor of about 2.5, on all
> IFs.    Tsys is normal, so again, we are losing signal.
>
>    d) Antenna 26C is weak by a factor of about 2.5, and Tsys is
> elevated by about a factor of 1.5 -- close enough to suggest this is the
> cause.
>    e) Antenna 26D gives no discernible fringes, and a bandpass
> indicating no signal.  Its Tsys reads 1800K (!), and is erratic.
>
>    f) Antenna 28C and 28D (LCP) fringes are low by a factor of about
> 5.  Again, Tsys is normal.
>
>    g) Antenna 7D is weak by a factor of 3.3, and an elevated Tsys (500K).
>
>    h)  Antenna 24B gives no fringes, and the bandpass is just noise.
> (The other IFs are fine, however).
>
>    i) All others look good, with antenna sensitivities within 20% of
> the median value.
>
>    Delays:
>
>    There are a number of significant delay errors, as listed below.
> The IF order is (A, B, C, D), in nsec.   The value is to be added to
> that which was used in the observation.
>
>    14:  0, -50, -20, -60
>    17:  0, -40, 0, -40
>    18:  -20, 0, -40, -50
>    23:  -20, -40, 0, -50
>    24:  +250, nofrg, +40, -40      **** Note delay error in IF 'A' ***
>    26: -30, 0, 0, nofrg.
>
>
>
>
>
>
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