September 2006 - Eagle (INACTIVE)

N1AL Award
by Tom Clark, K3IO 13 Sep '06

13 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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[Fwd: [amsat-bb] Re: S band downlink on P3E]
by Jim Sanford 09 Sep '06

09 Sep '06

Team: The kind of rational technical argument we should be prepared to answer. . . . 73, Jim -------- Original Message -------- Subject: [amsat-bb] Re: S band downlink on P3E Date: Thu, 7 Sep 2006 17:40:39 -0400 From: Jeff Griffin <kb2m(a)comcast.net> Reply-To: Jeff Griffin <kb2m(a)comcast.net> To: <amsat-bb(a)amsat.org> References: <01b401c6d28f$cc51d870$1001a8c0@RAFPavillion> <050e01c6d2ac$e29ff720$6401a8c0@KO4MA> Ok guy's, how about a test ? Why not everyone who is mode L/S capable get on AO-51 between September 11, and September 18th and post all results here? Or have another mode V/S session for the L band challenged? All we need is degree(s) of elevation worked, type of antenna, and rx environment, and quality of rx signal received. This should tell us what we want to know. I don't think there is a problem, as I worked up to 10 stations a pass last mode V/S session , and didn't hear anyone complain.... 73 Jeff kb2m ----- Original Message ----- From: "Andrew Glasbrenner" <glasbrenner(a)mindspring.com> To: "Rick Fletcher" <rfletcher(a)plumdragon.com>; "'AMSAT'" <amsat-bb(a)amsat.org> Sent: Thursday, September 07, 2006 2:38 PM Subject: [amsat-bb] Re: S band downlink on P3E > Rick, > > I am in _TOTAL_ agreement. I live in the suburbs of Tampa/St. Pete and > never > had an interference problem on my 3 foot dish. I have used the same dish > to > log well over a dozen WiFi access points in that immediate neighborhood. > With properly designed equipment, all that trash on 2.4 ghz goes away with > some elevation. What won't work is helixes with multiple sidelobes, and > surplus dishes that let one whole polarity of noise right thru the back. > > Everyone knows I'm a big supporter of AMSAT, but I gotta call it as I see > it. It makes me think of "bait and switch" to collect money for a project > featuring such a popular mode and then drop it. > > The loss of Mode B on AO-40 caused a lot of the hardcore AO-10/AO-13 types > to walk away, and that was tough to overcome. Now that we have, and we > have > people wanting S band, we leave them behind too. Even if it's a sound > engineering decision (and that hasn't been proven to me) it's a horrid > marketing decision. Bad mojo for a organization that lives on the > donations > of it's members. > > Sorry if this causes any pain to those involved with Eagle, but I needed > to > get it off my chest. > > 73, Drew KO4MA > AMSAT LM 2332 > > >>While AO-40 was still alive and I was working it from deep within "Silicon >>Valley", an area blanketed by WiFi, 2.4GHz cordless phones, etc., I >>discovered that a parabolic dish with a properly positioned and designed >>patch feed (slightly under-illuminating the dish and having no significant >>side-lobes) would bring in AO-40's S-band downlink very nicely and >>cleanly. > >>Of course, other feed or antenna types such as helical antennas/feeds were >>useless in that environment. > >>I have to admit that I don't buy the "too noisy" argument. > >>73, > >>Rick >>KG6IAL _______________________________________________ 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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[Fwd: Re: S band and Eagle: an appeal for a higher level discussion]
by Tom Clark, K3IO 08 Sep '06

08 Sep '06

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Last call for papers - Deadline Approaching
by Emily Clarke 01 Sep '06

01 Sep '06

2006 AMSAT North America Space Symposium 6-8 October 2006, Foster City, California Call for Papers: Final Call http://www.amsat.org/amsat-new/symposium/2006CallForPapers.php Invitation: Speakers are invited to submit and present papers dealing with the science of Amateur Radio Satellites and associated technologies for the AMSAT 2006 Space Symposium. The Symposium will be held at the Crowne Plaza Hotel in Foster City, California approximately 10km south of San Francisco International Airport. This is an annual Symposium, however the 2005 Symposium was cancelled due to hurricane damage caused by hurricanes Katrina and Rita. Speakers originally scheduled for the 2005 Symposium are invited to re-submit papers for the 2006 Symposium. Topics: Recommended topics include but are not limited to the following categories: · AMSAT P3E · AMSAT Eagle · Microsatellite Projects · Cubesat and Nanosatellite Projects · ARISS · Attitude Determination and Control · Propulsion · Communications · Mechanical · Antennas · Groundstations · Digital Modes · Education and Outreach · Launch Opportunities · Status Reports Other Activities: · The AMSAT Board of Directors will meet on 5-6 October. · The AMSAT Annual General Meeting (AGM) will be held on 6 October. · AMSAT International will meet 8 October · The IARU Satellite Committee will meet during the Symposium and will hold a public round table discussion on frequency coordination on 8 October · The ARISS International Delegates Meeting will be held on 9-10 October · "Birds of a Feather" sessions (BOFS) will be available on request Deadline: Applications for papers must be received ASAP. Papers must be submitted no later than 12 September 2006. Procedure: The planning committee has created an online registration system where you can submit your abstract and track it. Using this system you will allow you to submit your paper and any subsequent changes online. Visit the 2006 Symposium Paper Registration webpage for instructions: http://www.amsat.org/amsat-new/symposium/2006PapersProcedure.php Contact Emily Clarke, N1DID for additional information or Jean Fletcher KG6IAK for additional information Venue: See the 2006 Space Symposium web page for additional information about the venue.

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