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GET /hyperkitty/api/list/[email protected]/email/E43QMXVBZPDWL3TGAQFA5TNOVA35F7CY/?format=api
{ "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/E43QMXVBZPDWL3TGAQFA5TNOVA35F7CY/?format=api", "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api", "message_id": "[email protected]", "message_id_hash": "E43QMXVBZPDWL3TGAQFA5TNOVA35F7CY", "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/FEBDCQJ3PAKZ6UFGO4JPZNHRAZYXDDMR/?format=api", "sender": { "address": "n4qwf1 (a) gmail.com", "mailman_id": "8ff6e4ef2f9e4d82a21ee63d740aaf45", "emails": "https://mailman.amsat.org/hyperkitty/api/sender/8ff6e4ef2f9e4d82a21ee63d740aaf45/emails/?format=api" }, "sender_name": "John Price", "subject": "[amsat-bb] Re: S band downlink on P3E", "date": "2006-09-08T17:37:44Z", "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/PSK35MZOI4YT25LHOB26JAFTY63PCHXH/?format=api", "children": [], "votes": { "likes": 0, "dislikes": 0, "status": "neutral" }, "content": "and a big hi, hi....Thanks Bob for telling it like it is.\n\nOn 9/8/06, Robert McGwier <[email protected]> wrote:\n> Dave Guimont wrote:\n> >\n> >\n> >\n> >\n> > 73, Dave [email protected]\n> > Disagree: I learn....\n> >\n> > Pulling for P3E...\n> >\n>\n> As are many of us. That said, The S transmitter is not the primary\n> mode of P3E. The S band transmitter on P3E will be hooked to a dish.\n> This dish will have a half power beam width which will limit the\n> usefulness of the S band transmitter to those times of nadir pointing.\n>\n> The revelation of the results of our meeting, weeks before we could be\n> ready to explain carefully that we are taking a system approach to the\n> design of Eagle, is unfortunate. Not because the conclusions are made\n> public but because there is no context for the decision making process.\n>\n> We cannot build an AO-40 class spacecraft. We do not have the\n> personnel, the facilities, and we likely do not have sufficient talent\n> that we can devote to such an enterprise. We have talent in this\n> organization and around the world. But all of that talent leads a life\n> outside of AMSAT. As an engineering manager for AMSAT it is my\n> responsibility to make cold hard decisions based on personnel,\n> calculation, advice, studies, equipment availability, the\n> availability of launches that we can use and on and on.\n>\n> The organization overreacted to AO-40. It downsized Eagle\n> considerably. It set a goal of no motor. It said \"let's do digital\"\n> and \"give them a whip antenna on two meters\". It did not say this in a\n> crass manner but those were absolutely the conclusions of the\n> organization policies when captured into engineering possibilities.\n> It has literally taken me 11 months to ALMOST right the ship. If the\n> other people in the room will admit to it, I single handedly saved the\n> linear transponders in our current designs by\n>\n> a) picking the receiver designer\n> b) picking the transmitter designer\n> c) choosing SDX as the overall concept for the linear transponder\n>\n> EVERYONE is on board. But do you think such things are done overnight?\n> NO. They are done with leadership and not by whining. These decisions\n> and their outcome led to a MUCH improved antenna system, power\n> amplifier, and absolutely cutting edge efficiencies achievable for this\n> transponder in our current plans. It went from 25 kHz fed to a quarter\n> wave monopole on the back side of the spacecraft to serious antenna\n> absolute eating valuable territory on the business side of the\n> spacecraft and with bandwidth UP TO (but not necessarily) 100 kHz wide.\n> The bandwidth will be determined by the TYPE of customers we wish to\n> serve. We do not want to serve only those who can transmit 10 kW\n> EIRP. We do want to support 1 KW EIRP SSB contacts. We also want to\n> support a text messaging service that will require a shortened dipole on\n> 70cm and 2m which will not be limited to APRS users.\n>\n> The goals stated by the AMSAT board of directors for its next HEO\n> spacecraft design as a follow on to P3E (besides supporting P3E in the\n> interim) included aiding those people who live in CC&R (covenant\n> restricted) communities. It included aiding the first responders by\n> giving them the ability to take a back pack full of equipment, set it\n> up, and operate quickly. It stated that it wanted to produce a system\n> of such satellites over a decade to be available 7/24.\n>\n> We have a concept, not a design, for a spacecraft. This concept is an\n> \"upsizing\" of the near cubical Eagle. We are filling in the blanks on\n> the concept in an attempt to present a design.\n>\n> The concepts we are building to include the ability to use the\n> transponders on this spacecraft 365 days a year, in EVERY year the\n> spacecraft is functional and to try and build a spacecraft that will be\n> there and still usable when the third in the constellation is launched.\n> Do you think this is easy? Of course not. It is easy to pitch mud when\n> you are not responsible for an outcome.\n>\n> We are attempting to have NO bad seasons. We are attempting to have NO\n> funny orbital problems. We are attempting to have the gain antennas\n> solidly usable over 70% of the entire orbit. For these reasons and\n> because of the desire to serve the CC&R customers, this meant we had to\n> use microwaves to get sufficient gain on the antennas on the spacecraft\n> and the ground. We fully understand that Dick Jansson, Drew, Dave,\n> Tony, and others can give us anecdotes of how they can throw enough gain\n> on their antenna system and make S band work for them. I believe they\n> will not be happy with a 60 cm dish but will require a much larger dish\n> to be happy and I am certain they would do it. I do not care. They are\n> not who I am computing for. These are not the customers I am trying to\n> serve. The customers I want to serve for the future of AMSAT cannot be\n> served by a scratchy SSB signal and a (now) 4 foot dish. I have a\n> mission directive from the board of directors you elected and voted for\n> to serve these NEW customers. Those who will be here when the third\n> satellite is launched. They will not be where Dave will be by then. I\n> apologize for the crassness of this remark, but I am trying to make a\n> point. I know Dave and have for nearly 30 years.. We are building for\n> a guessed audience, with a guessed legal and RF environment, with a\n> guessed ability to deliver 3 such payloads over the next 13 years.\n>\n> COLD HARD CALCULATION went into this analysis based on our best guesses\n> and analyses. Given what we believe the environment will be We can\n> only do this on microwaves and we can only do it digitally. PERIOD.\n> End of story. God (as demonstrated through the mathematics of Claude\n> Shannon) has dictated this outcome. We did not sit in a back room and\n> decide what new toys we would throw your way to delight ourselves and to\n> screw you (no more smoke and no more drink in there, we have grown old\n> and boring) . To do it, I have to build a very complex antenna system\n> that will take up most of the available area on the spacecraft for\n> antennas. I cannot build a three axis stabilized spacecraft (I do not\n> have the team or the money to do it), so I must do it with phased\n> arrays. Matt Ettus has given us a great head start on this design and\n> Tom Clark and John Stephensen have done great work on the antennas so\n> far. We will test these antenna designs in the next twelve months\n> thanks to a very generous antenna test range offer and design help by\n> one of our members.\n>\n> The direction Jim and I gave our engineering team was that we cannot\n> rely on this to work perfectly and meet every operational goal\n> perfectly. STUFF HAPPENS. We are attempting to be ambitious but we\n> absolutely must have a credible back up in case this system does not\n> meet our expectations. We now have the upgraded Mode B transponder\n> design which I believe will be the sweetest one flown since Oscar 7's\n> Mode B. Fully equipped with the channelized AGC (Leila or Stella),\n> generating HELAPS with modern technology and new fantastic amplifier\n> components.\n>\n> I gave the argument to our engineering team that I have witnessed one\n> experimental, new widget after another get built, flown, and then have\n> its designers disheartened and dejected because it got \"RUDAK'ed\". It\n> never really gets used or fully developed. It drifts into an inert lump\n> that people mumble about when they are asked of their involvement. I\n> insisted on enough spacecraft power generation to run BOTH the linear\n> transponder and the digital transponder simultaneously and 365 days a\n> year, EVERY year. This is the single most expensive decision we have\n> made. We might spend 1/2 to 3/4 MILLION dollars on solar panels to\n> accomplish this. I have insisted we have enough antenna space to make\n> all of the antennas credible and based on calculation of the required\n> antenna gains to close the links. Again, Claude Shannon has\n> interpreted the natural laws and dictated the outcome. Cold hard\n> calculation has gone into the needed solar generators, and the size of\n> spacecraft required to support this.\n>\n> It will be about 4 feet across and look initially like a scaled DOWN\n> AO-40 at launch if the concept becomes our design.\n>\n> We cannot deliver the quality of services we are demanding of ourselves\n> if we fly all of the bands to be flown on P3E. We do not have the power\n> or the antenna territory to meet our goals for these services.\n>\n> I have taken my direction from the board of directors of this\n> organization. They made the vision statement. They can change it. You\n> elected them.\n>\n> Several things will happen in October. We will install four\n> directors. I may, or may not, be one of them. The board will vote\n> whether or not to retain me as the VP Engineering. I have made almost\n> NO ONE happy by slowing down those who drive me crazy with wanting to\n> rush head long in a ready fire aim approach by demanding that we\n> calculate our way to the vision statement to show the directors the\n> consequences of the decision making processes. I have to tell you, I\n> am damn proud of how much has been done in eleven months. Stuff got\n> put on hold that aggravated many. We all make decisions about the way\n> things have to go but I have done my best to aim us in a technically\n> feasible direction. I do not have time to do all the everyone wants me\n> to do. I will continue to do my best if I stay in the job.\n>\n> I offer the following. If the board votes to change their vision\n> statement and not to build the spacecraft we are proposing, I will\n> tender my resignation as VP Engineering since I will have failed to do\n> the job they elected me to do which was to produce a usable concept to\n> meet their vision. I am not interested in flying a carbon copy of P3E\n> when I know it makes no sense whatsoever. I am 52 years old and one of\n> the most active technical contributors in all of amateur radio. I will\n> not waste my time doing what I know in my heart and my head is not in\n> the best interests of amateur radio even if it is currently perceived to\n> be for the good of the shrinking aging membership of AMSAT. It would\n> be irresponsible of me not to attempt to aid the organization in\n> addressing a new group of members while attempting to thread the needle\n> of serving our current members. If elected to the board, and it changes\n> direction, I will offer my seat to the first alternate. Vote for\n> someone else if you do not want P3E built and you do not want the AMSAT\n> vision statement attempted if you have not cast your vote.\n>\n> The story you have just been told should not have come out in this\n> form. It was NEVER meant to be displayed in this form. The\n> calculations were made at the first of July. They have undergone\n> several iterations and were not really put in there latest form until\n> August. In an attempt to get further interest from the microwave\n> community, we made a decision to give a sneak peek to get some technical\n> aid from RF specialists. This has backfired badly because we, the\n> volunteers who have sacrificed countless hours on your behalf, have not\n> had the time to put together a hundred pages of supporting documentation\n> to tell the story in a coherent fashion so not only do we look like\n> idiots, we have had to do things like waste 3.5 hours writing this\n> silly note when I should have been asleep.\n>\n> Lastly. I have been accused here of being a con artist. I resent\n> it. I don't need to con anyone. Frankly, I don't have to be here at\n> all. I choose to be.\n>\n> Bob\n> N4HY\n>\n> --\n> AMSAT VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats,\n> NJQRP/AMQRP, QRP ARCI, QCWA, FRC. ARRL SDR Wrk Grp Chairman\n> \"You see, wire telegraph is a kind of a very, very long cat.\n> You pull his tail in New York and his head is meowing in Los\n> Angeles. Do you understand this? And radio operates exactly\n> the same way: you send signals here, they receive them there.\n> The only difference is that there is no cat.\" - Einstein\n>\n> _______________________________________________\n> Sent via [email protected]. Opinions expressed are those of the author.\n> Not an AMSAT-NA member? Join now to support the amateur satellite program!\n> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb\n>\n\n\n-- \n<<<<< N4QWF Amateur Radio Operator >>>>>\n<<<<< AO-7,AO-27,FO-29,SO-50,AO-51,VO-52,ISS >>>>>\n<<<<< Internet Email [email protected] >>>>>\n<<<<< Formerly KC4AHW VK3FEZ >>>>>\n<<<<< Amsat Member #27845 >>>>>\n<<<<< LON -79.25 LAT 37.45 Grid FM07 >>>>>\n<<<<< From the Foothills of the Blueridge >>>>>\n", "attachments": [] }