[amsat-bb] Re: 10mtr and Galileo

[Bill Ress]

John - a PS,

Maybe I was reading too much into Rick Hambly's response yesterday when he
stated that "we now have a band pan" without referring to L Band being in
the plan, digital or analog. Hopefully, that was just a minor oversight on
his part.

Regards...Bill - N6GHz

-----Original Message-----
From: John B. Stephensen [mailto:kd6ozh at comcast.net]
Sent: Sunday, September 10, 2006 11:18 PM
To: Bill Ress; jules at g0nzo.co.uk; amsat-bb at amsat.org
Subject: Re: [amsat-bb] Re: 10mtr and Galileo


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.

73,

John
KD6OZH

----- 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
ground
> ATC radar systems. It has been indicated that the Galileo receivers will
> need to consider these and other interference issues (like us) and build
in
> 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
Amateur
> 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
747.
> 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
interference.
>
> 3) Galileo, when (if) built out will employ 27 active satellites in a
medium
> earth orbit (23,616 km). I'm not sure how many satellites will be in view
at
> 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
be
> 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.
If
> that is the case, then the P3E folks are really using some good "science"
to
> 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
gaps
> 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
and
> the statement in the report that "there is the potential for most amateur
23
> cm transmissions to interfere with Galileo unless the Galileo receivers
are
> designed and built to withstand it".
>
> 73,
>
> John
> KD6OZH
>
> ----- 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
> launched:
> > http://news.bbc.co.uk/2/hi/science/nature/4566264.stm
> >
> > Also there was a study made by the UK microwave group (the body
> representing
> > 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
require
> a
> > little re-interpretation, with respect to satellite based reception. But
> as
> > 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
would
> > 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
a
> > >decision based on "crystal ball engineering" and not fact. I've even
read
> > >that if Galileo ever was launched - and that appears in the latest
press
> to
> > >be questionable" the US "would has threatened to shoot them down!"
> > >
> > >Regards...Bill - N6GHz
> >
> > _______________________________________________
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