[evlatests] P-Band Status

[Charles Kutz]

Antenna 13's P-Band is turning into a head scratcher at the moment. The 
crew swapped out the P-Band this afternoon and the LCP/RCP looked ok 
going into the T304, but there is a huge spike in the bandpass plots.

The P-Band that was removed checked out fine on the bench.

The P-Band was working at one time in A13. I'll talk to Rob in the morning.
We will probably remove the T304 and bring it back to the AOC for check 
out also.

Chuck

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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