Phase 4 versus Eagle discussion seen from Copenhagen, Europe
Hi all, I do not want to go into this discussion from a political point of view - just technical.
From my point of view looking at it from Copenhagen, the
most interesting thing is where the GEO is placed. A fast look at NOVA manipulating existing GEO satellite keps makes it clear that a position at around 90 degrees West will put NA and SA into the footprint (including Hawaii and Alaska). This position will place me outside the footprint - and most of Europe as well. If shifted to 60 degrees West I can just make it :-) That is with an elevation of 2.4 degrees and a range around 41400 km. If I can make it will amongst other factors depend upon the radiation pattern of the antennas on the satellite. Regarding frequencies I agree with Ed, KL7UW. Lots of us have the equipment and antennas to work L/S. Also any station able to work L2/S2 on AO-40 should be able to make it.
The comments above assumes SSB - but if we add the possibilities to use digital forms of (voice) modulation, we can add the advantage of Forward Error Correction.
A non technical comment: Go for both.
73 OZ1MY Ib
Ib,
I was only looking at my situation (and by default probably the rest of the Pacific). I hadn't really considered the EU footprint. These are good points to consider. Since I would assume a max constellation of three P4 sats the decision for location preferences will have to juggle maximum coverage vs overlap between continents. A wild guess is that enabling satellite linking may be the way for this instead of optimum intercontinental locations, but this should all be considered. Perhaps mid ocean locations would be more useful than over land locations? So 060W 180, 060E?
In the end it will also be determined by what Intelsat will offer.
Ed
At 05:50 AM 12/15/2007, OZ1MY wrote:
Hi all, I do not want to go into this discussion from a political point of view - just technical. From my point of view looking at it from Copenhagen, the most interesting thing is where the GEO is placed. A fast look at NOVA manipulating existing GEO satellite keps makes it clear that a position at around 90 degrees West will put NA and SA into the footprint (including Hawaii and Alaska). This position will place me outside the footprint - and most of Europe as well. If shifted to 60 degrees West I can just make it :-) That is with an elevation of 2.4 degrees and a range around 41400 km. If I can make it will amongst other factors depend upon the radiation pattern of the antennas on the satellite. Regarding frequencies I agree with Ed, KL7UW. Lots of us have the equipment and antennas to work L/S. Also any station able to work L2/S2 on AO-40 should be able to make it.
The comments above assumes SSB - but if we add the possibilities to use digital forms of (voice) modulation, we can add the advantage of Forward Error Correction.
A non technical comment: Go for both.
73 OZ1MY Ib
73, Ed - KL7UW ====================================== BP40IQ 50-MHz - 10-GHz www.kl7uw.com 144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w DUBUS Magazine USA Rep dubususa@hotmail.com ======================================
At 03:56 AM 12/16/2007, Edward Cole wrote:
Ib,
I was only looking at my situation (and by default probably the rest of the Pacific). I hadn't really considered the EU footprint. These are good points to consider. Since I would assume a max constellation of three P4 sats the decision for location preferences will have to juggle maximum coverage vs overlap between continents. A wild guess is that enabling satellite linking may be the way for this instead of optimum intercontinental locations, but this should all be considered. Perhaps mid ocean locations would be more useful than over land locations? So 060W 180, 060E?
Well, another assumption we could put in is that there would be some linking between the satellites. I'm sure that AMSAT or other keen people working in conjunction with AMSAT will want to setup ground stations specifically for inter-satellite links. Certainly over ocean locations could mean more single hop (i.e. via one satellite) DX paths. That would need to be balanced by the elevations in populated areas. A Pacific satellite would be the toughest there, given that the Pacific is a huge ocean.
In the end it will also be determined by what Intelsat will offer.
Indeed. In any case, I really hope this comes off. Even with current satellite modes (SSB/CW), Phase 4 makes it much more practical for me to work. I've never been in a situation where rotators have been practical (even for terrestrial work), but fixed antennas pointing at one patch of the sky are certainly do-able. I for one hope that we are able to make the most of this opportunity. LEOs are fun and a good intro to satellite operation and orbital mechanics, but in these parts, they're probably equivalent to a well sited repeater in LA that's turned on for 15 minutes several times a day, due to our lower population density (among satellite ops). I'm really looking forward to the next P3 or P4 (within range, of course!) bird, when the opportunity presents itself. :) P4 birds in the right places are especially interesting, but P3 (with a manual solution to the rotator problem ;) ) will be fun as well. It's a pity that AO-40 ran into problems, I was taking a lot of interest in it at the time it was launched and was considering equipment options, but things don't always go our way.
73 de VK3JED http://vkradio.com
participants (3)
-
Edward Cole -
OZ1MY -
Tony Langdon