Hello
Thanks for being invited to join the group.
For clarification, am I correct in reading that the plan is to formally propose S2 (3.4GHz) as the uplink for the ACP?
Regards
Grant Hodgson G8UBN
The plan is S2 (3.40-3.41 GHz) up and C (5.83-5.85 GHz) down. L (1.26-1.27 GHz) will also be an uplink band near apogee. The SD meeting proposal was S1/C but this conflicted with the L/S1 linear transponder. C/X would have consumed more DC power for the downlink.
73,
John KD6OZH
----- Original Message ----- From: "Grant Hodgson" grant@ghengineering.co.uk To: eagle@amsat.org Sent: Sunday, October 01, 2006 07:33 UTC Subject: [eagle] S2
Hello
Thanks for being invited to join the group.
For clarification, am I correct in reading that the plan is to formally propose S2 (3.4GHz) as the uplink for the ACP?
Regards
Grant Hodgson G8UBN _______________________________________________ Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Thanks to John and Jim.
I didn't want to upset the apple cart on my first post to the group, so I'll do it on my second...
I've just re-read Tom's presentation about Frequencies for Eagle. I'm a bit concerned about the proposal to use S2 up and C down for ACP - it would seem to make more sense to turn it round and make the uplink on C and the downlink on S2.
Advantages -
1) WiFi on 5.6GHz would not raise the receiver's noise floor significantly, unlike C down where future WiFi might raise the noise floor - like some locations now on S1. 2) Although the 3.4GHz band is not allocated to the satellite service in IARU Region 1, that doesn't stop the vast majority of users listening to an amateur satellite in that band. AFAIK the restrictions in R1, which are largely historical, are to prevent interference by amateurs.
Disadvantages
Users may suffer interference from Broadband Fixed Wireless Access (AKA WimAX) in Europe. WiMax transmitters will use relatively high power (50W or so), I don't know what the exact frequency plans are. HOWEVER - in the UK at least, there is some doubt that WimAX will be a commercial success - despite the hype put out by Intel et. al. It's very muddy waters, but we have a very good ADSL service to the vast majority of those that want it, and WiMAX will not be free - somebody will have to pay for a licence. So far in this country, every time somebody tries to come up with an alternative means of supplying broadband, they have failed - and on at least one occasion, spectacularly. So WiMAX is a total uncertainty.
Are there any other disadvantages to using C-S2? Generating power on 5.6GHz for the uplink is getting easier, almost by the day - there are some very interesting new FETs and MMICs becoming available, and the price/performance gets better all the time. And there are also some very interesting devices for the S2 downlink offering ever-higher performance, particularly better efficiency.
I've also read the report of the SD meeting in June; from what's on Eaglepedia it appears that the S2-C option didn't get much mention, maybe due to the uncertainty about the legalities of listening on a band that is not formally allocated. But AFAIK, there aren't many places in the world were it is illegal to intentionally listen to an amateur transmission, the exceptions of course being the countries where all activity above 500MHz is prohibited, who therefore don't get any microwave access anyway.
If the uplink is on S2 then Region 1 won't be able to use the ACP - period. At least, not until the IARU have managed to secure an allocation for the satellite service at 3.4GHz, and there is the possibility that not every country in R1 will adopt any IARU changes anyway, particularly if WiMax is adopted - or is even talked about. And I haven't seen any timescales for when the IARU would be able to make any changes - or even, if. Whilst many national organisations may want to get the 3.4GHz satellite allocation agreed, the international bodies - IARU included, can take a long time to come to formal agreement on such matters.
Region 1 is huge, and don't forget that Australia has lost it's 3.4GHz allocation as well. To potentially deny access to the ACP in most countries of the world might not go down very well, especially as it seems to me that there is an alternative.
I may have missed something; if so I apologise - I wasn't at the previous meetings, and I haven't got access to any of the attachements that were sent to posts on this list as they are not archived. I'm aware of the BOD meeting on Thurs/Fri and I wonder if there is still time to propose an alternative - I just don't have a good feeling about S2-C.
regards
Grant
The problem with an S2 downlink is that any of the countries that don't allow amateur transmission on that band could force ASMAT to turn off the downlink when their country is in the satellite's footprint.
73,
John KD6OZH
----- Original Message ----- From: "Grant Hodgson" grant@ghengineering.co.uk To: eagle@amsat.org Sent: Sunday, October 01, 2006 17:21 UTC Subject: [eagle] Re: S2
Thanks to John and Jim.
I didn't want to upset the apple cart on my first post to the group, so I'll do it on my second...
I've just re-read Tom's presentation about Frequencies for Eagle. I'm a bit concerned about the proposal to use S2 up and C down for ACP - it would seem to make more sense to turn it round and make the uplink on C and the downlink on S2.
Advantages -
- WiFi on 5.6GHz would not raise the receiver's noise floor
significantly, unlike C down where future WiFi might raise the noise floor - like some locations now on S1. 2) Although the 3.4GHz band is not allocated to the satellite service in IARU Region 1, that doesn't stop the vast majority of users listening to an amateur satellite in that band. AFAIK the restrictions in R1, which are largely historical, are to prevent interference by amateurs.
Disadvantages
Users may suffer interference from Broadband Fixed Wireless Access (AKA WimAX) in Europe. WiMax transmitters will use relatively high power (50W or so), I don't know what the exact frequency plans are. HOWEVER - in the UK at least, there is some doubt that WimAX will be a commercial success - despite the hype put out by Intel et. al. It's very muddy waters, but we have a very good ADSL service to the vast majority of those that want it, and WiMAX will not be free - somebody will have to pay for a licence. So far in this country, every time somebody tries to come up with an alternative means of supplying broadband, they have failed - and on at least one occasion, spectacularly. So WiMAX is a total uncertainty.
Are there any other disadvantages to using C-S2? Generating power on 5.6GHz for the uplink is getting easier, almost by the day - there are some very interesting new FETs and MMICs becoming available, and the price/performance gets better all the time. And there are also some very interesting devices for the S2 downlink offering ever-higher performance, particularly better efficiency.
I've also read the report of the SD meeting in June; from what's on Eaglepedia it appears that the S2-C option didn't get much mention, maybe due to the uncertainty about the legalities of listening on a band that is not formally allocated. But AFAIK, there aren't many places in the world were it is illegal to intentionally listen to an amateur transmission, the exceptions of course being the countries where all activity above 500MHz is prohibited, who therefore don't get any microwave access anyway.
If the uplink is on S2 then Region 1 won't be able to use the ACP - period. At least, not until the IARU have managed to secure an allocation for the satellite service at 3.4GHz, and there is the possibility that not every country in R1 will adopt any IARU changes anyway, particularly if WiMax is adopted - or is even talked about. And I haven't seen any timescales for when the IARU would be able to make any changes - or even, if. Whilst many national organisations may want to get the 3.4GHz satellite allocation agreed, the international bodies
- IARU included, can take a long time to come to formal agreement on
such matters.
Region 1 is huge, and don't forget that Australia has lost it's 3.4GHz allocation as well. To potentially deny access to the ACP in most countries of the world might not go down very well, especially as it seems to me that there is an alternative.
I may have missed something; if so I apologise - I wasn't at the previous meetings, and I haven't got access to any of the attachements that were sent to posts on this list as they are not archived. I'm aware of the BOD meeting on Thurs/Fri and I wonder if there is still time to propose an alternative - I just don't have a good feeling about S2-C.
regards
Grant _______________________________________________ Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
The problem with an S2 downlink is that any of the countries that don't allow amateur transmission on that band could force ASMAT to turn off the downlink when their country is in the satellite's footprint.
73,
John KD6OZH
OK, so maybe that's the thing I missed?
I don't know how this would work - I can't believe that an authority in one country can have any sort of power over a satellite organisation in another country. What if the satellite organisation refuse? Anyway, could a satellite, even at perigee, cause interference?
International co-ordination is beyond my level of knowledge and experience, but it is an essential part of the planning phase of a satellite project. Have the IARU satellite advisory panel been contacted about Eagle? There is no mention of it on their website - but they do mention a lot of other satellite projects, and their advisory board have some well known and respected members. I can't find any mention of the IARU in Eaglepedia.
http://www.iaru.org/satellite/
is worth a look.
regards
Grant
Hi Grant
For clarification, am I correct in reading that the plan is to formally propose S2 (3.4GHz) as the uplink for the ACP?
Welcome! Feel free to give me a call and I'll fill you in on the previous discussions to get you up to speed, as we've already discussed many S2 issues almost to death over the past few weeks, both regulatory and technical.
Cheers, Howard G6LVB +44 (0)771 076 3670
Didn't Australia loose only 3425-3600 MHz?
73,
John KD6OZH
----- Original Message ----- From: "Grant Hodgson" grant@ghengineering.co.uk To: eagle@amsat.org Sent: Sunday, October 01, 2006 17:21 UTC Subject: [eagle] Re: S2
Thanks to John and Jim.
I didn't want to upset the apple cart on my first post to the group, so I'll do it on my second...
I've just re-read Tom's presentation about Frequencies for Eagle. I'm a bit concerned about the proposal to use S2 up and C down for ACP - it would seem to make more sense to turn it round and make the uplink on C and the downlink on S2.
Advantages -
- WiFi on 5.6GHz would not raise the receiver's noise floor
significantly, unlike C down where future WiFi might raise the noise floor - like some locations now on S1. 2) Although the 3.4GHz band is not allocated to the satellite service in IARU Region 1, that doesn't stop the vast majority of users listening to an amateur satellite in that band. AFAIK the restrictions in R1, which are largely historical, are to prevent interference by amateurs.
Disadvantages
Users may suffer interference from Broadband Fixed Wireless Access (AKA WimAX) in Europe. WiMax transmitters will use relatively high power (50W or so), I don't know what the exact frequency plans are. HOWEVER - in the UK at least, there is some doubt that WimAX will be a commercial success - despite the hype put out by Intel et. al. It's very muddy waters, but we have a very good ADSL service to the vast majority of those that want it, and WiMAX will not be free - somebody will have to pay for a licence. So far in this country, every time somebody tries to come up with an alternative means of supplying broadband, they have failed - and on at least one occasion, spectacularly. So WiMAX is a total uncertainty.
Are there any other disadvantages to using C-S2? Generating power on 5.6GHz for the uplink is getting easier, almost by the day - there are some very interesting new FETs and MMICs becoming available, and the price/performance gets better all the time. And there are also some very interesting devices for the S2 downlink offering ever-higher performance, particularly better efficiency.
I've also read the report of the SD meeting in June; from what's on Eaglepedia it appears that the S2-C option didn't get much mention, maybe due to the uncertainty about the legalities of listening on a band that is not formally allocated. But AFAIK, there aren't many places in the world were it is illegal to intentionally listen to an amateur transmission, the exceptions of course being the countries where all activity above 500MHz is prohibited, who therefore don't get any microwave access anyway.
If the uplink is on S2 then Region 1 won't be able to use the ACP - period. At least, not until the IARU have managed to secure an allocation for the satellite service at 3.4GHz, and there is the possibility that not every country in R1 will adopt any IARU changes anyway, particularly if WiMax is adopted - or is even talked about. And I haven't seen any timescales for when the IARU would be able to make any changes - or even, if. Whilst many national organisations may want to get the 3.4GHz satellite allocation agreed, the international bodies
- IARU included, can take a long time to come to formal agreement on
such matters.
Region 1 is huge, and don't forget that Australia has lost it's 3.4GHz allocation as well. To potentially deny access to the ACP in most countries of the world might not go down very well, especially as it seems to me that there is an alternative.
I may have missed something; if so I apologise - I wasn't at the previous meetings, and I haven't got access to any of the attachements that were sent to posts on this list as they are not archived. I'm aware of the BOD meeting on Thurs/Fri and I wonder if there is still time to propose an alternative - I just don't have a good feeling about S2-C.
regards
Grant _______________________________________________ Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
John
Sorry, I should have verified the information I was told; various references mention that the 3.4GHz band was auctioned off, it wasn't until I found the actual bandplan that I got the truth.
The situation in Aus is actually quite complex; part of the band above 3425 was auctioned of for BFWA in certain areas. Consequently there are restrictions based on both geographical location and frequency.
3400-3410 IS available for the amateur satellite service. However, note 3 of the Australian bandplan for 3.4GHz says 'There are no amateur satellites operating or planned for this band'. Their bandplan document was last revised Sept 2006. Somebody had better tell the Wireless Instate of Australia about Eagle!
Sorry for the misleading information; I'm very pleased that they've got this allocation.
regards
Grant
Didn't Australia loose only 3425-3600 MHz?
73,
John KD6OZH
Hi Grant
For clarification, am I correct in reading that the plan is to formally propose S2 (3.4GHz) as the uplink for the ACP?
Welcome! Feel free to give me a call and I'll fill you in on the previous discussions to get you up to speed, as we've already discussed many S2 issues almost to death over the past few weeks, both regulatory and technical.
Cheers, Howard G6LVB +44 (0)771 076 3670
participants (4)
-
Grant Hodgson -
Howard Long -
Howard Long -
John B. Stephensen