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Re: "spontaneous" LEILA activation << I hear the pulses here too>> ?? A radar or ranger?? Lband or U band???



Yes, in deed, I noted the same effects during the time as
command station of AO-21.
There seems to be the same radar used in UK. AO-21
showed as a LEO, that the interfere was mostly when
the Satellite was visible from UK!
As result I had to use the east orbits from my location
to upload software.
Typical effect by the radar interfere are the cracks
in your own cw carrier.
It´s possible, that this pulses will start LEILA.....

73´s de Robert, DD4YR



Jesse Morris schrieb:

> The US Navy has had, for many years, ships with air search radars in the
> 420 to 450 Mhz frequency range which use pulse expansion/pulse
> compression type of modulation.  The technique is somewhat like a cross
> between spread spectrum and FM.  The pulse is generated by sending a
> narrow pulse down an LC type delay line (at a lower IF frequency).  The
> resultant pulse length is something on the order of 200 micro seconds
> long and contains a more or less linear phase (freq) shift from start to
> end.  On the receive end the process is reversed to recover the narrow
> pulse for processing.  This is a very high (average) power radar with a
> beam pattern looking up at the sky.  It could look somewhat like FM to a
> narrow band receiver. There should be a slow antenna rotation rate
> associated with this type of signal.
>
> There are also some airborne radars with actual swept frequency
> modulation methods which I hear often here in the Norfolk, VA area.
> There is a Navy axillary landing field a couple of miles from my QTH and
> when the AEW planes are flying there the interference on 435 is very
> severe.  It is a wideband signal which covers all of my 432 to 437 Mhz
> frequency range.  Fortunately the noise blanker takes them out almost
> completely so they do not cause me a major problem.  These are equivalent
> to the Air Force AWACS planes (the navy used to call them WF ("Willie
> Fudd")  but I don't know what they are named now.  These signals have the
> same type of slow rotation rate associated with them also.
>
> Actually there are many swept frequency type radars in various frequency
> bands in the military inventory that might cause interference on the
> AO-40 uplinks.
>
> 73's de Jess - W4MVB
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