[amsat-bb] "spontaneous" LEILA activation

[Estes Wayne-W10191 <W10191@xxxxxxxxxxxx>]

I frequently hear unexplainable LEILA sirens in the vicinity of 2401.400 MHz
where there is hardly ever any transponder activity.  Once this weekend I
was tuning across the transponder and heard the LEILA siren go nonstop for
more than 90 seconds.  I don't know how long the siren was going before I
stumbled onto it.  When I hear "spontaneous" LEILA sirens I verify that my
uplink signal is notched, just to ensure that nobody is uplinking a
recording of the LEILA siren.

Could there be a powerful U or L-band terrestrial interference source that
transmits brief pulses or high-speed data that is not audible on the AO40
downlink?  What other theories could explain why LEILA seems to activate for
no apparent reason?

Wayne Estes W9AE
Mundelein, IL, USA

----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org