Re: [amsat-bb] LEILA

["Graham Shirville" <g.shirville@xxxxxxxxxxxxxx>]

Over here in the UK we have a very loud radar that operates on the U band
uplink frequencies and beyond and has a variety of operating modes (pulse
widths/rates/frequency hops etc).

I believe there are a couple of other similar installations around the world
and maybe it is these that are triggering LEILA on what appear to be
unoccupied frequencies.

I am not sure how we could prove this other than asking for all the
installations to be turned off for a few hours and then seeing whether this
cures the problem!

I believe the L band RX has a radar noise blanker (we have lots of air
traffic control radars in Europe all over the 1260-1270 band)
but I am not sure the U band RX is similarly equipped or, if it is, whether
the circuitry is designed to cope with this particular type of transmission.

Maybe a good look at the output spectrum of the transponder may show radar
type pulses?

IMHO

cheers

Graham G3VZV

> LEILA frequently "scolds" me when I'm not even transmitting.  That is, I
> frequently hear the LEILA siren while tuning around empty portions of the
> AO40 transponder.


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