[evlatests] C and X Wideband Tests

[Rick Perley]

    A test of observing in 1 GHz-wide wideband mode, cycling between X 
and C bands was done Saturday night.  The results are very impressive 
indeed!

    This was another test of 'demo science' on Hercules A.  The idea is 
to observe the entire C-band from 4 to 8 GHz, and all of X-band (current 
receivers) from 8 to 9 GHz.  To test this, I made a script to cycle 
around the following loop:

    Cal, Cband, 4 -- 6 GHz for 50 seconds
    Herc A, C-band, 4 -- 6 GHz, for 90 seconds
    Herc A, C-band, 6 -- 8 GHz, for 90 seconds
    Cal, Cband, 6 -- 8 GHz, for 50 seconds
    Cal, X-band, 8 -- 9 GHz, for 50 seconds
    Herc A, X-band, 8 - 9 GHz, for 90 seconds.

    This loop was repeated four times. 

    Results:

    1)  All scans were observed, *except* for the final pair at X-band. 

    2)  In general, the data are very fine for all three tunings. 

    Problems common to all three tunings:

    a) All 8 subbands from antenna 11, IF 'B' had a very incorrect 
passband.  There are 'suckouts' appearing between the 2nd and 3rd 
subbands, and between the 6th and 7th. 
    b) All data from antenna 22, IF 'B' were integer zero.  (No data 
delivered). 
     c) Antenna 27 requires a huge delay correction -- about 55 nsec. 
   
    Problem specific to C-band:

    Antenna 16, IFs A and B (RCP) gave no fringes -- only noise. 

    Problems specific to X-band:

    a) Antenna 7 gave no fringes (as reported by Ken, I believe).
    b) Antenna 9, IFs C and D (LCP) gave no fringes -- only noise. 

      
    A more thorough report may come tomorrow (time permitting). 

    On the basis of these very good results, I think we can move ahead 
with the long version of the program.