[evlatests] L-Band RFI

[Michael Rupen]

These data were taken on 14jul09 in the late afternoon (~3:30-5pm).

          Michael

On Wed, 15 Jul 2009, Rick Perley wrote:

>
>    A new observation at L-band gave me some decent looks at our current
> environment.  A few interesting issues ...
>
>    1) Radar signals are easy to identify because of their regular
> pulsing (really cool to see in SPFLG!).  We have radar signals at:
>
>    1254.5, 1300.0, 1310.0, 1320.0, 1330.0, and 1338.0 MHz.  The signals
> at 1300, 1320, and 1338 are very weak.   None of these will cause any
> future troubles, as they are nowhere near strong enough to contaminate
> adjacent channels (after Hanning-like smoothing).  Zap the affected
> channel, and move on ...
>
>    2) In the past we've had *huge* signals, very wide in frequency,
> centered near 1245 MHz.  These are definitely not radars.  However, in
> this new observation, these are virtually absent.
>
>    3) The entire band between 1929 and 1989 MHz is occupied with what I
> believe are cell emissions.  (Dan -- is this right?)  In the more
> distant past (a couple years ago), these were entirely open.  The
> signals are quite strong.  Pity.
>
>    4) The two 128-MHz-wide bands centered at 1435 and 1820 MHz are
> almost entirely free of RFI.
>
>    5) The internal 1408.0 MHz birdie, reported on a few days back, is
> still with us, with the same characteristics as reported earlier.
>
>    Rick
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