[evlatests] New (?) RFI in Ka-band

[Ken Sowinski]

On Fri, 15 Jan 2021, Wes Grammer via evlatests wrote:

> 30976 MHz is the second harmonic of 15488 MHz, which is one of the L301 
> tuning frequencies. A stretch, but was the L301 on any of the antennas set to 
> this frequency during the observation?

Bingo.

L301-1: 15488
L301-2: 11904

Irrelevant, but the L302s were: 12036, 13916, 14036, 11916

I also note that this is not really new.  Rick lodged the same
complaint in November 2016.  At that time the strongest responce
was seen in ea25 with a few nearby antennas.

Ken

> On 1/15/2021 10:42 AM, Ken Sowinski via evlatests wrote:
>>  On Fri, 15 Jan 2021, Vivek Dhawan via evlatests wrote:
>> 
>>>
>>>  on second (or rather the first real) thought, my statement is
>>>  false if the firstLO is not a exact multiple of 128.
>>
>>  But the first LO is constrained to be a multiple of 128.
>>  See my email of a moment ago.
>>
>>>  On Fri, January 15, 2021 10:37, Vivek Dhawan via evlatests wrote:
>>> |  Ken, Rick,
>>> | 
>>> |  I believe it cannot be a harmonic of 128, because any of
>>> |  these falls in a null between subbands, by construction.
>>> | 
>>> |  On Fri, January 15, 2021 09:24, rperley via evlatests wrote:
>>> | |  ... however, I'll note here that no other RFI spikes were seen in
>>>  the
>>> | |  entire Ka band.  So why just this particular harmonic?
>>> | | 
>>> | |  Rick
>>> | | 
>>> | |  On 2021-01-15 11:14, Ken Sowinski wrote:
>>> | |>  On Thu, 14 Jan 2021, rperley via evlatests wrote:
>>> | |> 
>>> | |>>  New data, taken Tuesday afternoon, reveals an unresolved birdie in
>>> | |>>  Ka-band.
>>> | |>>  Frequency = 30.975 GHz.
>>> | |> 
>>> | |>  128*242 = 30976
>>> | |> 
>>> | |>  That seems pretty close.
>>> | |> 
>>> | |>  Ken
>>> | |> 
>>> | |>>  Very strong -- equivalent to a couple of Jy in 128 MHz width. 
>>>  (That's
>>> | |>>  BIG).
>>> | |>> 
>>> | |>>  Rick
>>> | |>> 
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>>> | |>> 
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