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
Hi Jules,
Thanks a bunch for referencing your link. It is a MUST READ for EME and satellite operators - not to mention AMSAT leadership.
That link was the source of my earlier comments, including the remark about the "US jamming or worse" (the worse alluding to taking the satellites down)."
I would like the AMSAT decision makers to detail the reasoning for dropping the L-Band Uplink like a hot potato besides the "Galileo" excuse. As yet, I can't find it in Eagelpedia.
In view of Peter Blair's (G3LTF) paper (PLEAS SEE JULES LINK BELOW) I cannot see any rational for dismissing Eagle use of the L-Band satellite Uplink allocation. I don't thing using the statement that "we will lose our L-Band allocation" is indicative of the much appreciated "science" the team is bringing to the Eagle design process.
Now if it was a trade-off between the Eagle uplink being at S-Band, as is now propose, instead of at L-band on the basis of limited space, current, etc., that's one thing. I could understand that decision.
By the way, the Galileo "shoot down" was me being dramatic. The US and the EU have since signed an agreement for making the technical standards between GPS and GNSS compatible and allowing "countries" to disable the capabilities over certain regions (which satisfied the US concerns).
Regards...Bill - N6GHz
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org]On Behalf Of jules@g0nzo.co.uk Sent: Sunday, September 10, 2006 4:38 PM To: amsat-bb@amsat.org 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
----- Original Message ----- From: "Bill Ress" bill@hsmicrowave.com To: jules@g0nzo.co.uk; amsat-bb@amsat.org Sent: Monday, September 11, 2006 3:16 AM Subject: [amsat-bb] Re: 10mtr and Galileo
I would like the AMSAT decision makers to detail the reasoning for dropping the L-Band Uplink like a hot potato besides the "Galileo" excuse. As yet, I can't find it in Eagelpedia.
In view of Peter Blair's (G3LTF) paper (PLEAS SEE JULES LINK BELOW) I cannot see any rational for dismissing Eagle use of the L-Band satellite Uplink allocation. I don't thing using the statement that "we will lose our L-Band allocation" is indicative of the much appreciated "science" the team is bringing to the Eagle design process.
Regards...Bill - N6GHz
Hi Bill, N6GHZ
Hopefully for P3E the L-band has been supported but I can't understand why not for EAGLE
Just in view of possible interference with Galileo and the primary uplink L1 of P3E from 1268.725 to 1268.875 MHz a Galileo Alternative uplink L2 has been chosen for linear transponder from 1263.225 to 1263.375 MHz
L2 will be switched on just in case in the future we cannot transmit in L1 but for P3E the L-band has not been abandoned.
Read please here part of the letter RE [amsat-bb] INFO ON P3E sent by Peter DB2OS to amsat-bb on 15 April 2006 wich is fully available in the AMSAT-BB archives.
-------------------------------------------------------------------
Quoting Peter DB2OS
Hi Domenico and All,
some clarification...
1) the 2nd L-band linear Passband Uplink "P3E Galileo Alternative" was originally choosen to be from 1260.100 to 1260.250 MHz and has been moved to 1263.225 - 1263.375 MHz.
............omitted
The 2nd L band uplink was allocated exactly to the first minimum of spectral density of GALILEO E6-A which is 1263,520 MHz (frequency of the E6-A carrier is 1268,520 MHz and chip rate 5 MHz). The 2nd or secondary L2 Gallileo alternative uplink will only be chosen if the primary L1 uplink can not be used.. it's just a switch in the transponder.
73s Peter, DB2OS
----------------------------------------------------------------
73" de
i8CVS Domenico
One thing may not be clear to all AMSAT members. There is still an L-band receiver in the Eagle requirements document for the analog transponder. The San Diego meeting recommendation was to move the digital transponder uplink from C to S. So far, no decision has been made to eliminate the L-band analog uplink.
The analog transponder has a U uplink so if L becomes inaccessible, it still works. The digital transponder has no secondary receiver so its uplink frequency is more critical.
73,
John KD6OZH
I would like the AMSAT decision makers to detail the reasoning for dropping the L-Band Uplink like a hot potato besides the "Galileo" excuse. As yet, I can't find it in Eagelpedia.
In view of Peter Blair's (G3LTF) paper (PLEAS SEE JULES LINK BELOW) I cannot see any rational for dismissing Eagle use of the L-Band satellite Uplink allocation. I don't thing using the statement that "we will lose our L-Band allocation" is indicative of the much appreciated "science" the team is bringing to the Eagle design process.
Hi John,
I have just re-read the Eaglepedia report of the San Diego meeting.
I must admit I continue to be shaken by Tom Clark's early statement about his views on the L-Band situation and then with the table called "Band Usage" which states L-Band usage (for digital) "Discarded due to possible L-band loss". I realize that this was referring to DIGITAL band allocations and that later a table called "preliminary power budget" includes 3 watts for a L-Band ANALOG receiver but I have been concerned that this position about digital L-Band is based on the unsubstantiated and unproven notion about the "government(s)" taking us off the air there.
John, I think engineering decisions should be based, as much as possible, on real facts and data - not a notion about the future.
Now another question. Why can't the L-band analog receiver (if it remains) be used for digital modulation (i.e. digital backup). Down to an IF frequency or modulation detection frequency it shouldn't care if the modulation is analog or digital. Have I missed something?
Regards and thanks for your patience and time responding to my posts.
Regards...Bill - N6GHz
-----Original Message----- From: John B. Stephensen [mailto:kd6ozh@comcast.net] Sent: Sunday, September 10, 2006 10:59 PM To: i8cvs; Bill Ress; jules@g0nzo.co.uk; AMSAT-BB Subject: L band
One thing may not be clear to all AMSAT members. There is still an L-band receiver in the Eagle requirements document for the analog transponder. The San Diego meeting recommendation was to move the digital transponder uplink from C to S. So far, no decision has been made to eliminate the L-band analog uplink.
The analog transponder has a U uplink so if L becomes inaccessible, it still works. The digital transponder has no secondary receiver so its uplink frequency is more critical.
73,
John KD6OZH
I would like the AMSAT decision makers to detail the reasoning for dropping the L-Band Uplink like a hot potato besides the "Galileo" excuse. As yet, I can't find it in Eagelpedia.
In view of Peter Blair's (G3LTF) paper (PLEAS SEE JULES LINK BELOW) I cannot see any rational for dismissing Eagle use of the L-Band satellite Uplink allocation. I don't thing using the statement that "we will lose our L-Band allocation" is indicative of the much appreciated "science" the team is bringing to the Eagle design process.
We might be able to use the L receiver as a backup, depending on the final digital transponder design, but it would only work well near apogee. The digital transponder needs to work over 75% of the orbit so that it's just as available as the U/V analog transponder. This mandates a phased array antenna with multiple receive paths. It's unlikely that all receivers in the array will fail so a backup receiver on another band isn't a big issue.
73,
John KD6OZH
----- Original Message ----- From: "Bill Ress" bill@hsmicrowave.com To: "John B. Stephensen" kd6ozh@comcast.net; "i8cvs" domenico.i8cvs@tin.it; jules@g0nzo.co.uk; "AMSAT-BB" amsat-bb@amsat.org Sent: Monday, September 11, 2006 06:47 UTC Subject: RE: L band
Hi John,
I have just re-read the Eaglepedia report of the San Diego meeting.
I must admit I continue to be shaken by Tom Clark's early statement about his views on the L-Band situation and then with the table called "Band Usage" which states L-Band usage (for digital) "Discarded due to possible L-band loss". I realize that this was referring to DIGITAL band
allocations
and that later a table called "preliminary power budget" includes 3 watts for a L-Band ANALOG receiver but I have been concerned that this position about digital L-Band is based on the unsubstantiated and unproven notion about the "government(s)" taking us off the air there.
John, I think engineering decisions should be based, as much as possible,
on
real facts and data - not a notion about the future.
Now another question. Why can't the L-band analog receiver (if it remains) be used for digital modulation (i.e. digital backup). Down to an IF frequency or modulation detection frequency it shouldn't care if the modulation is analog or digital. Have I missed something?
Regards and thanks for your patience and time responding to my posts.
Regards...Bill - N6GHz
-----Original Message----- From: John B. Stephensen [mailto:kd6ozh@comcast.net] Sent: Sunday, September 10, 2006 10:59 PM To: i8cvs; Bill Ress; jules@g0nzo.co.uk; AMSAT-BB Subject: L band
One thing may not be clear to all AMSAT members. There is still an L-band receiver in the Eagle requirements document for the analog transponder.
The
San Diego meeting recommendation was to move the digital transponder
uplink
from C to S. So far, no decision has been made to eliminate the L-band analog uplink.
The analog transponder has a U uplink so if L becomes inaccessible, it
still
works. The digital transponder has no secondary receiver so its uplink frequency is more critical.
73,
John KD6OZH
I would like the AMSAT decision makers to detail the reasoning for dropping the L-Band Uplink like a hot potato besides the "Galileo" excuse. As yet, I can't find it in Eagelpedia.
In view of Peter Blair's (G3LTF) paper (PLEAS SEE JULES LINK BELOW) I cannot see any rational for dismissing Eagle use of the L-Band
satellite
Uplink allocation. I don't thing using the statement that "we will
lose
our L-Band allocation" is indicative of the much appreciated
"science"
the team is bringing to the Eagle design process.
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
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@amsat.org [mailto:amsat-bb-bounces@amsat.org]On Behalf Of John B. Stephensen Sent: Sunday, September 10, 2006 7:47 PM To: jules@g0nzo.co.uk; amsat-bb@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@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
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@hsmicrowave.com To: "John B. Stephensen" kd6ozh@comcast.net; jules@g0nzo.co.uk; amsat-bb@amsat.org Sent: Monday, September 11, 2006 06:02 UTC Subject: RE: [amsat-bb] Re: 10mtr and Galileo
Hi John,
Consider this.
- 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.
- 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.
- 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.
- 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.
- 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@amsat.org [mailto:amsat-bb-bounces@amsat.org]On Behalf Of John B. Stephensen Sent: Sunday, September 10, 2006 7:47 PM To: jules@g0nzo.co.uk; amsat-bb@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@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 - 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@comcast.net] Sent: Sunday, September 10, 2006 11:18 PM To: Bill Ress; jules@g0nzo.co.uk; amsat-bb@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@hsmicrowave.com To: "John B. Stephensen" kd6ozh@comcast.net; jules@g0nzo.co.uk; amsat-bb@amsat.org Sent: Monday, September 11, 2006 06:02 UTC Subject: RE: [amsat-bb] Re: 10mtr and Galileo
Hi John,
Consider this.
- 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.
- 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.
- 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.
- 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.
- 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@amsat.org [mailto:amsat-bb-bounces@amsat.org]On Behalf Of John B. Stephensen Sent: Sunday, September 10, 2006 7:47 PM To: jules@g0nzo.co.uk; amsat-bb@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@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
--- jules@g0nzo.co.uk wrote:
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
For me the key point is that Peter estimated that a single Amateur Radio beacon operating at 1296 MHz such as that at Martlesham could force every Galileo receiver out of lock over a radius of 16 km (10 miles).
It's not just the increase in noise floor that needs to be considered, it's the concern that a typical Amateur station will jam Galileo receivers over a wide area. If at some point in the future that transponder were used for what might be losely interpreted as "safety critical" applications then would forsee Amateur Radio activities either being suspended or power levels being severely curtailed in 1260-1300 MHz.
Now it's going to be 2012 before they get the Galileo system fully operational so we should at least get 4 years use out of the P3E "L" uplink. What happens post 2012 is a big unknown.
73 Trevor M5AKA
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Hi Trevor,
Agreed that a terrestrial 1.2 GHz Amateur transmission can cause interference to Galileo, so will the ground ATC radars and myriad of other possible signals like the 3rd harmonic of 420 to 433 MHz signals or harmonics of high power TV transmitters (and the list goes on).
In light of this, Galileo is stated to have the capability to "detect, isolate and mitigate interference." They have a two year study program called MAGIC to work the issue of interference (see galileoju.org).
Also see: http://uranium.stu-dif.com/QuickPlace/sensors-processing/PageLibraryC12570C1 005A34E8.nsf/h_Index/6A2577AA3F531D6BC12570C1005A49F6/?OpenDocument
I would guess that the result of the study could provide one of two conclusions: 1) they can technically handle interference or 2) they can't and will insist that governments take Amateurs, ATC radars and any other interferers off the air.
I'm thinking 1) will prevail and we can all rest easy until the next financially lucrative use of the frequencies comes about.
But your right - we're looking at 4 to 5 years before we'll know what is reality.
Regards...Bill - N6GHz
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org]On Behalf Of Trevor Sent: Monday, September 11, 2006 2:04 PM To: AMSAT BB Subject: [amsat-bb] Re: 10mtr and Galileo
--- jules@g0nzo.co.uk wrote:
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
For me the key point is that Peter estimated that a single Amateur Radio beacon operating at 1296 MHz such as that at Martlesham could force every Galileo receiver out of lock over a radius of 16 km (10 miles).
It's not just the increase in noise floor that needs to be considered, it's the concern that a typical Amateur station will jam Galileo receivers over a wide area. If at some point in the future that transponder were used for what might be losely interpreted as "safety critical" applications then would forsee Amateur Radio activities either being suspended or power levels being severely curtailed in 1260-1300 MHz.
Now it's going to be 2012 before they get the Galileo system fully operational so we should at least get 4 years use out of the P3E "L" uplink. What happens post 2012 is a big unknown.
73 Trevor M5AKA
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participants (5)
-
Bill Ress -
i8cvs -
John B. Stephensen -
jules＠g0nzo.co.uk -
Trevor