September 2006 - Eagle (INACTIVE)

Re: [Advisors] Re: Re: [Fwd: Re: S band and Eagle: an appeal for ahig...
by RaySoifer＠cs.com 17 Sep '06

17 Sep '06

In a message dated 9/17/06 3:08:03 PM Greenwich Standard Time, kd6ozh(a)comcast.net writes: > Path loss is 15 dB less at 435 MHz than 2400 MHz and antenna gain is 13 dB > less. However, the noise figure is 5 dB higher, so almost twice the EIRP wll > be required on a U uplink than an S uplink. The 70 cm receiver has a 200 kHz > bandwidth so some class 2 (4800 bps) uplinks could be accomodated. Since they > will be BPSK and use FEC, I assume that they will occupy at least 15 kHz > each and will have to be spaced at least 25 kHz apart. This could allow 4 > uplinks. It's not good to increase the receiver bandwidth as it will let in more > PAVE PAWS interference. > > John, I was thinking in terms of an additional 70 cm receiver to accommodate several conference-grade channels, for those users who may be prohibited from using BOTH L-band and S-band uplinks (think Europe). Yes, PAVE PAWS is there, sometimes, but it would still be better than no digital access at all. Also, it's not a certainty that PAVE PAWS will even be there in 2020. 73, Ray

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San Diego Meeting report
by Jim Sanford 14 Sep '06

14 Sep '06

All: It has come to my attention that the San Diego meeting report has format problems. I've ZERO idea how the format got gooned. I have taken it offline for correction. I will advise, tomorrow or Saturday, when I've fixed the format and reloaded. Thanks & 73, Jim wb4gcs(a)asmat.org James A. Sanford, PE Amsat Eagle Project Manager

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Team Speak tomorrow night
by Jim Sanford 13 Sep '06

13 Sep '06

Team: I'm not going to be able to put an agenda on EaglePedia until tomorrow. Things I'd like to discuss: 1. Budget submissions -- I have some, what else is ccoming? What estimates are coming? 2. Status reports -- what should I highlight at Symposium in my BRIEF remarks? Who is making what presentations? 3. Did we write off L-band or not in San Diego? I remember, and my notes and one other attendee confirm, that we wrote off L-band for the digital uplink, but briefly discussed it as ananalog uplink. We never made a decision. Lets discuss and decide. 4. Status reports from those we haven't heard from in a while -- power, sensors, etc. 5. Bob and Rick discussed on the phone, (I was next to Rick) the idea of: Rethinking S2 (3GHz) for the Digital uplink This frees up S1 for any use We offer that anyone willing can develop and submit for testing and qualification a stand-alone L/S transponder to fly in one of the TSFR slots, using fixed antennas. It would be usable at/near Apogee, like the microwave packages on AO-13 and A)-40. What do you think? Les's discuss this. Any other topics? Remember 2100 EDT, 1800 PDT. Thanks & 73, Jim wb4gcs(a)amsat.org

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Analog transponder revisited
by Howard Long 13 Sep '06

13 Sep '06

Folks, Under AOB last night I raised a question regarding there apparently being no analog transponder on board as far as I can see in recent documentation. I was of the impression that a parallel analog transponder would be flying as well as the SDX. I am concerned that as this was a hot issue several months ago, I would respectfully request that we clarify the situation at the next meeting prior to the Symposium. 73, Howard G6LVB

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FW: Re: Team Speak tomorrow night
by Howard Long 13 Sep '06

13 Sep '06

Hi Bob > I know from documentation I received from I8CVS that this will > exclude Italy from the digital payload. > I am expecting to hear from several other countries that, excluding > action from a WARC, they will be excluded from the digital > communications package if we use S2. I think it was clear from the meeting last night that there are two options for the wide band DCP that will be proposed for further discussion. Rick will propose a version with both L and S2 uplinks and a C downlink. John will propose a version with C uplink and X downlink (I wasn't sure if an L uplink was also included). In Rick's proposal, as L will still be available so Region 1 with their current allocations, Region 1 will have access to the DCP whether or not S2 is available to us. It seemed clear from last night's discussion that the assessment to drop L band at San Diego wasn't the right decision. There was also some discussion about whether the high bandwidth digital mode would be viable at L band, probably limited by a non-steerable RX antenna on the spacecraft and uplink EIRP, although somehow I doubt Domenico has a problem with with uplink EIRP ;-) As it's being revisited again in the next couple of weeks, we can go over these again in further detail with the benefit of both your's and Tom's input. Cheers, Howard

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N1AL Award
by Tom Clark, K3IO 12 Sep '06

12 Sep '06

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[Fwd: [amsat-bb] Re: S-Band allocation]
by Jim Sanford 11 Sep '06

11 Sep '06

Team: I forward this because the 5MHz bandwidth is news to me. I heard talk in SD about 10MHz BW for the digital signals. This would exclude the JAs. I know we're a long way from nailing this down, just sharing the data. 73, Jim -------- Original Message -------- Subject: [amsat-bb] Re: S-Band allocation Date: Mon, 11 Sep 2006 19:26:43 +0900 From: T.Komatsu <ruruko63(a)po30.lcv.ne.jp> To: AMSAT BB <amsat-bb(a)amsat.org> References: <20060911083016.63490.qmail(a)web25310.mail.ukl.yahoo.com> Hi, Alls, Please do not forget that there are many amateurs who are in big interest in Japan too. And satellite allocation on this band is 2,400 to 2,405, within whole of the allocated band for amateur, 2,400 to 2,450MHz. There is no amateur allocation on 2300MHz band for us. 73s Toyo JA0CQP _______________________________________________ Sent via AMSAT-BB(a)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

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DCP Bands
by Matt Ettus 11 Sep '06

11 Sep '06

In the time since the San Diego meeting, I have come to realize that: 1 - Nothing is ever final. 2 - The decision about bands for the DCP (digital communications payload) is likely to be made in some combination of the following venues, in none of which you are likely to find me: A - AMSAT-BB B - AMSAT Board Meetings C - Meetings with shadowy DoD figures without names D - IARU, ITU, ARRL, QCWA, or Wuoff-Hong Society meetings 3 - Many of the decision makers (especially those speaking the loudest) think that SSB is the way of the future and Shannon's Law means that sex offenders have to register with the police. 4 - It really doesn't matter to me which bands are chosen, as long as they meet certain basic criteria. In that spirit, I decided to distill the major technical constraints which we agreed on at the San Diego meeting, in order to give a basic set of rules which would provide us a workable bandplan for this satellite. The only legal/regulatory constraint I applied to this list is that we are unlikely to GAIN privileges. Someone else can decide how likely we are to lose them. The constraints, and their reasons, as I see the consensus from the SD meeting: 1 - The uplink band must be chosen from the set of { L, S1, S2, C }. The lower bands simply don't have the bandwidth necessary for what we want to do, and would have unwieldy antennas. The higher bands are much more difficult due to the pointing accuracy required for antennas and the difficulty of generating significant power and low noise figures. 2 - The downlink band must be chose from the set of { S1, S2, C }. The same reasons as constraint #1, with the added constraint that L-band is not legal for downlink (which falls under the "we're not likely to GAIN privileges" category). 3 - The uplink and downlink bands must be distinct. This means no C-C or S1-S1. The bands are simply too narrow to allow for practical duplexers in the quantity we are talking about (~36). 4 - The uplink band must not be used by any other payload on Eagle as a downlink. Obvious interference issues. 5 - The downlink band should not be used by any other payload as an uplink. Obvious interference issues. 6 - Sharing of uplink bands or downlink bands MAY be possible, but probably isn't necessary. Taking constraints 1-6 together, the choices are (in the form A/B where A is up, B is down): { L/S1, L/S2, L/C, S1/S2, S1/C, S2/S1, S2/C, C/S1, C/S2 } In addition to the above "hard facts", we can add in the following concerns which were expressed at the meeting: 7 - We would prefer not to use S1 as a downlink because of possible interference from WiFi devices. 8 - Fear of L being taken away 9 - Uncertain legality of S2 in ITU Region 1 This leads to the following matrix, which I believe effectively boils down the decision process from the SD meeting: Bandplan 7 8 9 L/S1 X X L/S2 X X L/C X S1/S2 X S1/C S2/S1 X X S2/C X C/S1 X C/S2 X The only bandplan with no X's is S1/C, which is what we chose at the meeting. Obviously, there are now additional concerns which have been raised: - S1-Uplink being taken away - #8 not being as big a deal as we thought. This would change the matrix. I welcome your thoughts, especially if you feel I have misrepresented the SD meeting consensus. Thanks, Matt, N2MJI

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Eagle S-Band & L-Band decisions
by Larry Brown 10 Sep '06

10 Sep '06

I have been following this discussion for a number of months now both on the Eagle discussion group and on AMSAT-bb. I don't want to add to the noise on amsat-bb but do have an opinion. I want to hear the satellite as well as possible so if that means abandoning 2.4 Ghz as a downlink, I can live with the decision. I am not happy with the prospect but I realize that you can't fight physics. I do plan to borrow a spectrum analyzer and examine how bad the situation is around my house in Tucson. Before we lost the L1 transmitter and the dish antenna on AO-40 I was hearing the bird very well with a minimal antenna and poor noise figure down-converter. The AO-40 S-band downlink took a huge hit when all we had was the S2 transmitter and the helix antenna. I have spent the best part of 15 years selling S-band as the satellite downlink of choice to satellite users so it is very hard to now have to start selling another answer, but so be it. My BIG concern is giving up the L-band uplink without a fight based on the assumption that at some time in the future we may lose the band due to a system that has not even been fielded yet. While the Galileo system will probably be fielded, let's not give them the benefit of the doubt. Even if it is fielded we do not automatically lose the allocation. It looks to me like our potential for interference is relatively minor compared to the real issues that they face on the E5 links in the radiolocation band where there are aircraft transponders, DME transponders, DME interrogation links, Link-16 Data Links and numerous other radio navigation emitters and radars. I personally don't think that they will even notice us. I have seen one or two places where they are selling the Safety of Life services as being jam resistant and these capabilities are spread out among all of the downlinks. Since L-band only involves a receiver on the satellite and antenna space that could also be shared with other receivers if necessary (with well designed stacked patch antennas or feeds), I think that an L-band receiver should be flown (unless we lose the allocation prior to launch). In making this statement I am assuming that the cost of adding an L-band uplink is not excessive. I think we should plan on using the band and then turn off the receiver if we lose the allocation. It is part of our responsibility to use and defend our bands to the best of our ability and the L-band uplink is very valuable to us. Many of us have existing equipment and are L-band terrestrial or EME users and we need L-band on the satellite to help defend our rights to the band. Have a back-up or alternate uplink in case we do lose L-band at but plan to fly and use it as long as possible. We can inform our members that the band is at risk and then it is their choice if they invest in new L-band equipment. We should make it be the government (not AMSAT) that takes away our access to this band. There are my thoughts. I will happily adapt to whatever decision that AMSAT's management and the Eagle design team make. I am looking forward to seeing many of you at the TAPR/DCC conference next weekend. Larry Brown, W7LB

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Netherlands, S band problems
by Robert McGwier 10 Sep '06

10 Sep '06

All of this hoopla about S band in the AMSAT bulletin board, which thankfully is blocked to me because comcast has chosen to blackball amsat.org (oh drat, the block just got removed ;-) ) caused me to do some talking, searching, thinking. We are definitely NOT at the end of this story. I believe the Netherlands has lost 2400-2540. I am investigating with some help how universal this is. What I believe we are seeing is that like here, the licensed operators are supposed to be protected but what actually happens is that when the licensed operators interfere severely with the 802.11 use, the amateurs are summarily dismissed. It is my opinion that we got bloody lazy. We took the ITU/IARU tables as found on the web and took them as gospel. We need to understand the actual reality as found on the ground. If we cede L band as an uplink, and we see a definite trend towards loss of 2400-2540 because of 802.11 across Europe, we are close to being between a rock and a hard place. Thanks to Lee, a study that was pointed out called ARIA. This, commissioned by Paul Rinaldo at the League was EXACTLY what we are after. It is a study of the rise in noise floor at 2400 due to 802.11. Paul is a) helping me get the results and b) attending our symposium and giving a talk on frequencies. Rick and I spent an hour in discussions with a very high ranking general officer at the Pentagon in a position to have an opinion worth listening to. His opinion is that our band at L band is NOT in danger from Galileo. I will not go into greater detail here and I will never put his remarks in a public record. But suffice it to say, his remarks have indeed caused me to go investigate this. We did our TECHNICAL job in San Diego. We have NOT done our regulatory job and our political job and it has caused many to write me in private about existing situations. I am afraid we are about to be made to look as if we are knuckling under to pressure and it will have nothing to do with the pressure. It will have everything to do with this story getting out before we were ready to tell and had done all of our home work. If the serious impact of 802.11 resulting in loss of 2400 MHz uplink privileges in region 1 and 2 and 3 can be substantiated, then that is a fait d'accompli we must take into account. The loss of privilege, in every case I know of, results from BLOODY ATV users blocking 802.11 users. If we transmit and block, we can cause the same kind of problem. We need to understand how widespread this phenomenon is. We now can document it has happened in LU. I am given to understand by a European who should know that it is true also in the Netherlands. We must find out how widespread. Given loss of 2400 as a fact (should we find this widespread and growing), I would risk using L band and 3400 instead rather than lose the ability to use our satellite altogether within a very short period following launch. Should we find this to be necessary, then we have a tough job to decide how, or whether to do 23cm, 9cm, or both and if we do both, can we put credible antennas on the spacecraft. I believe Rinaldo is coming to tell us the cold hard facts of life. Be prepared to listen. I am also going to ask questions in the amsat-bb to try to elicit first hand knowledge of loss of this band from lurkers there. Bob N4HY -- AMSAT VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP/AMQRP, QRP ARCI, QCWA, FRC. ARRL SDR Wrk Grp Chairman "You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat." - Einstein

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