[evlatests] RFI birdie in Ka-band

[Evangelia Tremou]

Thanks, Ken. Indeed, it makes sense.

Rick and I were just looking at the yesterday's data and there is no 
birdie at 28808 MHz.

Lilia


On 8/18/23 15:21, Ken Sowinski wrote:
> On Fri, 18 Aug 2023, Evangelia Tremou wrote:
>
>> Looking at some test data taken yesterday (Ka_3bit_23A256*), the 
>> 30.976GHz birdie is not present.
>>
>> The scripts was using:
>>
>> LoIfSetup(True,"33GHz",35900,37900,28500,30500,1)
>
> This sets L301-1 to 14404 MHz, so if there were a birdie I would expect
> to see it at 28808 MHz in this case.
>
> Ken
>
>
>> Lilia
>>
>>
>> On 8/18/23 09:59, Ken Sowinski via evlatests wrote:
>>>  On Thu, 17 Aug 2023, Rick Perley via evlatests wrote:
>>>
>>>>  I find a fairly strong 'birdie' in Ka-band -- at 30.976 GHz. This 
>>>> is the
>>>>  242nd multiple of 128 MHz.  Don't know if this is relevant ...
>>>
>>>  This was in 23A-317 observed on July 17, 2023 using
>>>
>>>       LoIfSetup(True,"33GHz",37500,35500,33500,31500,1)
>>>
>>>  Which resulted in an L301-1 setting of 15498 MHz, the second harmonic
>>>  of which is 30976 MHz.
>>>
>>>  We have previously seen such birtdies in Ka band with a variety
>>>  of tunings; some of them much stronger than this one.  I don't
>>>  know if anyone was able to show whether it was really the second
>>>  harmonic getting into the RF, or some other path with the same
>>>  outcome.
>>>
>>>  Ken
>>>
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>>