[evlatests] L30x Comb generator RFI.

[Travis Newton]

Vivek Dhawan wrote:

>I got a spectrum of the (unshielded) L300 comb generator measured by
>Colton Dunlap and Mertely, 1-18GHz. I picked off some strong lines and
>tried to find them on the VLA system. 1408 and 22272 were seen.
>8192 was missed in the first attempt but WAS seen subsequently -
>(my notes were sketchy, I have reloaded the archive data to
>make sure). 8448 was weak on 2 occasions.
>
>4608 was very strong on the lab spectrum but not seen on the VLA.
>
>It was not clear if these birdies were really in the RF band, or leaking 
>in somewhere in the IF.
>
>When this was reported back in January, I was told:
>
>1. that the comb generators were different on production antennas
>compared to 14 and 16 (what flavour is 13?).
>  
>
Antennas 13,18,24 have a single 128 and 512 MHz comb generator in the L300.
Antennas 14 and 16's L302's each have a 128 MHz comb generator and the 
L301's each have
a 512 MHz comb generator


>2. And that Hollis had a design to shield the comb generators but it
>had not yet been implimented.
>  
>
no shield has been implemented
Travis


>I intend to run these tests again as soon as its deemed useful.
>
>Vivek.
>
>
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