[amsat-bb] Re: Galileo interference on L band
domenico.i8cvs at tin.it
Wed Sep 20 21:15:52 PDT 2006
----- Original Message -----
From: "John B. Stephensen" <kd6ozh at comcast.net>
To: "Marc Franco" <lu6dw at yahoo.com>; <amsat-bb at amsat.org>
Sent: Wednesday, September 20, 2006 10:13 PM
Subject: [amsat-bb] Re: Galileo interference on L band
> The article predicts that there may be limitations on the amateur service.
> The biggest problem is sidelobes from the antenna that can be of either
> polarization sense. A 16 kW EIRP uplink can easily generate 500 W EIRP
> sidelobes (15 dB down) within the Galileo receiver passband and,
> the calculations outlined in the article, they can cause interference from
> 42 km away.
Hi John, KD6OZH
Does this imply that all 23 cm EME stations including G3LTF will have to
move away from 1296 MHz ?
> ----- Original Message -----
> From: "Marc Franco" <lu6dw at yahoo.com>
> To: <amsat-bb at amsat.org>
> Sent: Wednesday, September 20, 2006 19:03 UTC
> Subject: [amsat-bb] Galileo interference on L band
> > John,
> > Galileo is circularly polarized, so using the opposite
> > polarization sense will help.
> > An excellent paper on Galileo interference was written
> > by Peter Blair, G3LTF, a well known moonbounce
> > authority and outstanding engineer. The paper can be
> > found following this link:
> > http://www.southgatearc.org/articles/galileo.htm
> > 73, Marc N2UO
> > --- "John B. Stephensen" <kd6ozh at comcast.net> wrote:
> >> Unfortunately, the Gaileo downlink covers 1258-1299
> >> MHz, the first satellite
> >> has been lanched and the satellites in the
> >> constellation will be on over the
> >> entire world. Our uplink antennas have sidelobes
> >> that are 10-20 dB down, so
> >> a 1 kW EIRP SSB uplink results in 10-100 W radiated
> >> towards terrestrial
> >> receivers. A 256 kbps uplink would require 16 kW
> >> EIRP and be 0.5-1 MHz wide.
> >> P3E has a second L receiver tuned to a null in the
> >> Galileo signal (there is
> >> only one null in the 1260-1270 MHz band) but no one
> >> knows if this will help.
> >> SSB users can move to the U uplink if L is a
> >> problem. However, this only
> >> works for narrowband signals. A wideband uplink
> >> won't fit in the null and
> >> can't move down in frequency.
> >> 73,
> >> John
> >> KD6OZH
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