[amsat-bb] Re: 10mtr and Galileo
John B. Stephensen
kd6ozh at comcast.net
Sun Sep 10 23:17:47 PDT 2006
Its not NIH but conservatism. With no secondary receiver, we need to be
certain that there will be no problems in the future. If we were certain
that there will be no government intrusion, then L band would be better as
there are more high-power amplifiers avalable off-the-shelf today.
----- Original Message -----
From: "Bill Ress" <bill at hsmicrowave.com>
To: "John B. Stephensen" <kd6ozh at comcast.net>; <jules at g0nzo.co.uk>;
<amsat-bb at amsat.org>
Sent: Monday, September 11, 2006 06:02 UTC
Subject: RE: [amsat-bb] Re: 10mtr and Galileo
> Hi John,
> Consider this.
> 1) Galileo operating frequencies are already co-located with existing
> ATC radar systems. It has been indicated that the Galileo receivers will
> need to consider these and other interference issues (like us) and build
> anti-jamming capabilities. Our GPS system upgrades are already working
> further in this direction.
> 2) Amateur L-Band satellite transmissions from a single operator would
> typically occur for short periods of time. A moving vehicle (car or plane)
> with a Galileo receiver would quickly be moving itself away from an
> transmission site. So statistically the chances for interference between a
> fixed Amateur transmission and a plane or car have to be very, very small
> and then only for a very short period. I've seen AMSAT comments about the
> possibility of an Amateur L-Band satellite transmission bringing down a
> Don't think so.
> 3) I understand that interference could cause loss of acquisition lock but
> that code reception would "free-wheel" until lock is restored. In other
> words, already there appears to be a way of handling momentary
> 3) Galileo, when (if) built out will employ 27 active satellites in a
> earth orbit (23,616 km). I'm not sure how many satellites will be in view
> any one time but one must consider that not all visible satellites signals
> will be interfered by an Amateur L-Band satellite transmission which will
> using rather directional antennas.
> 4) I understand that the P3E folks have already worked out a solution by
> locating their L-Band operations in what will be a Galileo spectrum null.
> that is the case, then the P3E folks are really using some good "science"
> develop their satellite L-Band operations. Good for them!!
> Hey - I'm not in the thick of it - but it seems there are some serious
> in communication between AMSAT-DL and AMSAT-NA even though we read about
> glimpses of real technical exchange. I hope we're not falling for the NIH
> (Not-Invented-Here) syndrome.
> Regards...Bill - N6GHz
> -----Original Message-----
> From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org]On
> Behalf Of John B. Stephensen
> Sent: Sunday, September 10, 2006 7:47 PM
> To: jules at g0nzo.co.uk; amsat-bb at amsat.org
> Subject: [amsat-bb] Re: 10mtr and Galileo
> What bothered people is the fact that we need high power L-band uplinks
> the statement in the report that "there is the potential for most amateur
> cm transmissions to interfere with Galileo unless the Galileo receivers
> designed and built to withstand it".
> ----- Original Message -----
> From: <jules at g0nzo.co.uk>
> To: <amsat-bb at amsat.org>
> Sent: Sunday, September 10, 2006 23:37 UTC
> Subject: [amsat-bb] Re: 10mtr and Galileo
> > Just for the record, the first Galileo satellite has already been
> > http://news.bbc.co.uk/2/hi/science/nature/4566264.stm
> > Also there was a study made by the UK microwave group (the body
> > UK amateur interests above 1GHz), which makes interesting reading. It
> > suggests that the signals from Galileo would have little impact on
> > terrestrial/EME 23cms opperation. Obviously the conclusions woule
> > little re-interpretation, with respect to satellite based reception. But
> > Galileo transmissions will presumably be aimed at the earth, so that any
> > amatuer satellite will receive signals greater than that on earth, for a
> > minute part of it's orbit, I would think that the conclusions drawn
> > still be valid. It's an interesting read:
> > http://www.microwavers.org/papers/iaru/C5-13_Galileo.pdf
> > Jules
> > G0NZO
> > >Speaking of allocations being taken away, I just can't fathom the AMSAT
> > >decision to drop L-Band up because of the "Galileo Affair." Now that's
> > >decision based on "crystal ball engineering" and not fact. I've even
> > >that if Galileo ever was launched - and that appears in the latest
> > >be questionable" the US "would has threatened to shoot them down!"
> > >
> > >Regards...Bill - N6GHz
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