[evlatests] Ku-band RFI -- how bad it can be...

[Dan Mertely]

Ah.  I see. So it's a clear case of "Doctor, Doctor, it
hurts when I beat my head against the wall ...."  Actually
it's good to get a deep look at just what's out there--
thanks!  -Mert


On 10/18/2019 1:58 PM, Rick Perley wrote:
>      Dan:
> 
>      It probably has been this bad for a long time -- rather poor 
> sampling of the data!  I don't often look at X and Ku-band at objects in 
> the 'Clarke' belt.
> 
>      Rick
> 
> On 10/18/19 1:56 PM, Dan Mertely wrote:
>> Hi Rick. I'm surprised that the band seems worse than before.
>> The low Ku band, "Fixed Satellite, (space-to-earth)" (read GSO)
>> allocation is 11.7-12.2 GHz.  Then from 12.2-12.7 is the broadcasting
>> satellite down-link band.  Above that are the uplinks, which we are
>> unlikely to see (none nearby).  So 11.7-12.7 GHz should have been
>> very noisy for years.  -Mert
>>
>> On 10/18/2019 11:40 AM, Rick Perley via evlatests wrote:
>>>      I distributed yesterday a 'waterfall' plot of severe X-band RFI, 
>>> affecting the upper half of the band.
>>>
>>>      Unsurprisingly, it extends well in Ku band.  Attached here is a 
>>> similar plot, for the spectral range 12 -- 14 GHz.  This is a very 
>>> short baseline (N1 x N2), with 1 second averaging, and 2 MHz spectral 
>>> resolution.  Time runs vertically, frequency horizontally.  The 
>>> X-axis is labeled in terms of spectral window and channel.
>>>
>>>      The source is 3C273 -- the 'dark' side of the plot, at the 
>>> higher frequencies, is RFI free, and is at a level of 18 Jy. The 
>>> grey-scale is logarithmic, with the maximum at 567 Jy.
>>>
>>>      The RFI cuts off at 12.7 GHz.  Above that (at least to 16 GHz), 
>>> the spectrum is really clean.
>>>
>>>      Rick
>>>
>>>
>>>
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