John I am confused
Please provide something to cure my problem
I believe at this point that the Galileo bird transmits to receivers on the ground in the current amateur mode L up link spectrum. Right or wrong? What frequency in the same amateur L mode spectrum is the Galileo using for receiving.
Joe Murray K0VTY Amsat #860 ============== On Mon, 11 Sep 2006 02:47:22 -0000 "John B. Stephensen" kd6ozh@comcast.net writes:
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@g0nzo.co.uk To: amsat-bb@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
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the
author.
Not an AMSAT-NA member? Join now to support the amateur satellite
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Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Galileo transmits on 1260-1300 MHz and 1215-1300 MHz is now allocated to global positioning systems (up to 5 of them). Amateur transmissions can desense the earth-based receivers. Tests on U.S. GPS receivers showed that a 1W EIRP CW signal 10 km away would cause inteference. It would be better if 1260-1270 MHz was a downlink for amateur satellites.
73,
John KD6OZH
----- Original Message ----- From: "joseph Murray" k0vty@juno.com To: kd6ozh@comcast.net; amsat-bb@amsat.org Sent: Monday, September 11, 2006 03:11 UTC Subject: Re: [amsat-bb] Re: 10mtr and Galileo
John I am confused
Please provide something to cure my problem
I believe at this point that the Galileo bird transmits to receivers on the ground in the current amateur mode L up link spectrum. Right or wrong? What frequency in the same amateur L mode spectrum is the Galileo using for receiving.
Joe Murray K0VTY Amsat #860 ============== On Mon, 11 Sep 2006 02:47:22 -0000 "John B. Stephensen" kd6ozh@comcast.net writes:
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@g0nzo.co.uk To: amsat-bb@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
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the
author.
Not an AMSAT-NA member? Join now to support the amateur satellite
program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
John B. Stephensen wrote:
Galileo transmits on 1260-1300 MHz and 1215-1300 MHz is now allocated to global positioning systems (up to 5 of them). Amateur transmissions can desense the earth-based receivers. Tests on U.S. GPS receivers showed that a 1W EIRP CW signal 10 km away would cause inteference. It would be better if 1260-1270 MHz was a downlink for amateur satellites.
73,
John KD6OZH
John,
You are neglecting real word conditions...future civilian airborne GPS/GNSS/Galileo receiver systems are going to have to incorporate anti-jam capabilities. A few do already and changes in the signal coding for the new civilian GPS downlink will have a much more robust capability when it comes to interference rejection. I also believe Galileo will too employ a more jam resistant signal waveform.
There are much greater threats to these systems than ham operators from a real-world technical perspective. However, I will concede that government agencies may eliminate amateur use of L-Band for political reasons...an easy, but meaningless way for them to show they are taking action.
However, until and if the hammer comes down, there are currently no strong technical reasons to eliminate L-Band uplinks.
Bruce
participants (3)
-
Bruce Rahn -
John B. Stephensen -
joseph Murray