[evlatests] L-Band RFI -- again

[Dan Mertely]

Hi Rick.  I discussed the RFI with Tom Banks of the DoD Spectrum
control office @ WSMR.  He said the frequency 1484 MHz was being
used by Eclipse Aviation for jet test telemetry.  They were to
provide scheduling information to Tom, but had failed to do so.
Tom called Eclipse, and they then called me today.  They are
indeed using 1484 MHz frequently, and have lately, occasionally
been using it over the CATO MOA (here at the plains of San Agustin).

Tom's contact at Eclipse Aviation (Garrett Woody) said that they
have been using both 1484 and 1443.5 MHz for telemetry for nearly
3 years now, without coordination, but that they will be coordinating
through Tom @ WSMR from now on.  (Indeed, I have been monitoring
telemetry at 1444 MHz for a couple of years now, and believed it was
caused by Kirtland or Holloman AFB test flights over the Rio Grande
valley.)  Garrett said that they can use 1444 MHz vs. 1484 MHz if we
prefer.  I told him that both are within our default channels, but that
1444 is nearer the edge, and therefore probably a bit less disruptive to us
at this time. I also briefed him on our operations, and discussed dynamic
scheduling, and how, with a bit of advanced notice, some of our L-band
observation scheduling is flexible.

Garrett said that they would try to get as specific as possible in
their future frequency coordination through Tom, but that atmospheric
conditions drive their test times.  When not dictated by weather factors,
he said that their typical operating times are (as we have observed)
from around 7 AM to 2 PM, local time.  They never test at night, and
only sometimes on weekends.

As I begin getting their schedule, I will forward it to the operators,
and whoever else indicates they have an interest.

-Mert



Rick Perley wrote:
>     A continuum L-band observation was taken near noon.  The first 
> observation, at 11:53 through 11:58 MST, was completely wiped out -- all 
> the hallmarks of RFI.   By far the worst offenders are clustered at the 
> center of the array -- antennas 6, 9, 10, 12, 15, 20 and 24.  The second 
> observation was taken at 12:37 through 12:42 -- these data are just 
> fine.   A check done a few minutes ago (2PM), show all is fine. 
> 
>     I note that the time of wipeout was just before lunchtime, and was 
> at the same local time as yesterday's spectral line observation which 
> was wiped out by an *enormous* emission centered at 1484 MHz.   Might we 
> have some microwave oven gone wild?  Or perhaps some piece of equipment, 
> used intermittently? 
> 
>    
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