[evlatests] More on S-band birdies ...

[Dan Mertely]

It has the sound of being the 128 MHz comb output from the
L300 reference, being up-converted by the L301 which uses the
comb as a reference.  ...Maybe different manufacturing
"techniques" produce slightly different leakages in the L301?
At 9cm, different wiring placement within the module might
attenuate some lines, while enhancing others.

Terry Cotter could render a more insightful opinion.

-Mert


Rick Perley wrote:
>     In looking at the autocorrelation spectra, we find the peculiar RFI 
> at S-band is more peculiar than previous reported:
> 
>     The separation between the birdies is 128 MHz, not 256MHz.  They are 
> all 'centered' at 3200 MHz.  Different antennas show different RFI 
> lines, but all of them are n*128 MHz away from 3200 MHz. 
> 
>     In this experiment, subband 6 contains 3200 MHz in channel 577.  
> (Because the subband separation is 128 MHz, all birdies are in channel 
> 577 of the relevant subbands). 
> 
>     Antenna 8 shows them strongly in subbands 4, 6 and 8, and weakly in 
> subband 7
>     Antenna 9 has a very strong signal in subband 5, and none in any other!
>     Antenna 15 shows them weakly in subband 6 and 8.
>     Antenna 24 has it only in subband 6.
>     Antenna 27 shows them weakly in subbands 6 and 8.
>     Antenna 28 shows it strongly in subbands 4 and 8. 
> 
>     An explanation is wanting ...
> 
>    
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