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

[Ken Sowinski]

Can anyone explain why this ancient message just appeared in my mailbox?

Ken


On Fri, 15 Jan 2021, Ken Sowinski via evlatests wrote:

> 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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>