February 2007 - Eagle (INACTIVE)

TeamSpeak conference for Tuesday 13 Feb
by Jim Sanford 23 Mar '07

23 Mar '07

Team: Our next TS conference will be Tuesday night at 2100 EST, 1800 PST, 0200 ZULU. The agenda is posted on the TeamSpeak conferences page of EaglePedia. Please add to it and join us Tuesday night. Note: I'll be travelling to VA and the weather is looking ugly (to be kind), so I might be a few minutes late. If I don't show up, please press on and take good notes. Thanks & 73, Jim wb4gcs(a)amsat.org

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Info for the ANS Bulletins this week?
by JoAnne Maenpaa 23 Feb '07

23 Feb '07

Hi everyone, This seems to be a quiet week for general AMSAT and satellite info for the ANS Bulletins. Perhaps its an opportunity to provide a shot of longer range information about what AMSAT is up to? 1. Anything that can be said about Eagle? 2. Anything that can be said about the New Lab or University projects? 3. Anything that can be said about P3E? 4. Plans for Dayton? 5. Early info for the next Symposium? If you have anything please send the info to me by Saturday afternoon? I'll get it formatted into the final form for the bulletins ... just having the info helps the ANS editors a lot! Thanks! -- 73 de JoAnne K9JKM k9jkm(a)amsat.org Editor, AMSAT News Service

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URx
by Dick Jansson-rr 21 Feb '07

21 Feb '07

John: Per your suggestion, I have examined your data for the U band Receiver. I shall first examine the power supplies for the receiver. The data that I have elicited from your information is as follows, powers in Watts: Device Dissipation Delivered U16 0.340 0.850 U17 0.411 U18 0.384 1.200 U19 0.108 0.090 U20 0.040 0.224 ------------ ------------ Totals 1.283W 2.364W For a grand total power dissipation of the power system of 3.647W. Of the delivered power you have identified two devices that suck up (U2 = 0.490W and U3 = 0.388W) a total of 0.878W. It is not clear where the remaining 1.486W is dissipated. Your help in identifying where this thermal energy is dumped in the module would be helpful, just to make sure that no stone remains unturned in this matter of handling these dissipations. Hot resistors could be an issue of concern...... You talk (somewhat glibly) of sinking regulator devices to PCB copper pads and such. For at least five devices, U2, U3, U16, U17, & U18 I consider that such mounting is not acceptable as such concentrated dissipations, exacerbated by the vacuum environment, must be treated more specifically in achieving heat sinking to the module housing. The module Base Plate, drawing E05 21, being of somewhat robust 1.6mm thick aluminum should help significantly in dissipating these module powers. More direct thermal coupling methods are going to be needed in this module to get that heat to the Base Plate. PCB thermal conductivities, even enhanced by added copper, are not good at all and cannot really be depended upon in these situations. With this module "pushing" the envelop of module power rating, baring a full heatsink module, it is clear that the coatings of the module will not be bare aluminum. This raises the ante in the picture of keeping command-level modules from getting too cold in the eclipse situation. The original concept for maintaining full control of the spacecraft through a 3 hour eclipse, where the spaceframe can be as low as -130°C or lower, low power, command-sensitive modules would not become dangerously cold, provided that their dissipations are indeed low and the thermal coatings highly reflective. If on the other hand we depend upon higher dissipation modules, such as this URx, then the module temperatures may be a concern in the eclipse situation. This is all subject to detailed analytic examination upon the construction of a full spacecraft analytic model, which we do not have at the moment, we first need a detailed mechanical design before having that analytic model. In any event, this URx presents a significant thermal challenge. Solving this challenge first needs an understanding of the physical bodies of these devices of the forenoted concern. Can you provide me with the physical information on these devices, either directly or by URL? Can you also respond to my earlier question on where the rest of the power dissipation resides? By one means or another we need to engineer a more direct thermal connection between these devices and the E05 21 Base Plate, which may require some inventiveness of our collective crania. '73, Dick Jansson, KD1K (ex: WD4FAB) kd1k(a)amsat.org ---------------------------

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adding stuff to amsat.org
by Phil Karn 18 Feb '07

18 Feb '07

I had pizza with Brian Kantor WB6CYT Saturday night. He said somebody in AMSAT, possibly Rick, had asked for root access for the amsat.org machine so that various new functions could be added. I wasn't sure (and neither was Brian) of the specific new functions to be added, but they seemed to be various forms of engineering support. Brian is concerned, and I agree with him, that these additions might risk the stability and security of a stable machine already relied upon very heavily by everyone in AMSAT for email reflector and web services. Problems might come from the new services themselves, or from the much larger set of administrators with root access that would surely result. For example, counter to the assumptions of some, the amsat.org machine doesn't run Linux; it runs BSD Unix. They're similar in many ways, but there are crucial differences that anyone with root access must be aware of. Computers, even rackmount servers, just aren't so expensive or hard to come by that we have to cram everything on a single box. If there's need for another new server to handle AMSAT engineering-related services, I'm sure we could come up with a new box and host it at either UCSD (where Brian would manage it) or Qualcomm (where I would manage it.) Just let me know what's really needed, and we can make it happen. Phil

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Proposed Eagle Antenna Arrays
by Louis McFadin 15 Feb '07

15 Feb '07

This is a repeat of the earlier e-mail. Here is a proposal for arranging the Eagle antennas that Stan Wood and I worked out today. By moving the 2M dipoles to the corners we have sufficient room for full sized elements over the ground plane. The 2M antennas should get about 8dB. Three L band patches in cavities should give us greater than 12 dB gain. By putting the S1,S2 and C band patches in hex shaped cups we maximize the available space. The cup arrays can be NC machined out of a solid blank and therefore attain precise control of the spacing. It may also serve as heat a radiating device. Each patch will be circular polarized and fed with a single feed from it's matching amplifier. The 70 CM Circular polarized patch should have around 6 dB gain. We will look at getting more gain on 70 cm. Seven S1 patches will be mounted on top the 70CM patch. They should get about 15dB gain. Tom's S2 interferometric patches are included. Omni antennas similar to that used on P3D will be required on the opposite side of the spacecraft. There should also be room for the Sun Sensors on both sides of the spacecraft. Lou McFadin W5DID w5did(a)mac.com _______________________________________________ Via the Eagle mailing list courtesy of AMSAT-NA Eagle(a)amsat.org http://amsat.org/mailman/listinfo/eagle Lou McFadin W5DID w5did(a)mac.com

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TeamSpeak ports
by John B. Stephensen 15 Feb '07

15 Feb '07

What ports does TeamSpeak require other than 8767 for UDP and 9274 for TCP? 73, John KD6OZH

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Regrets (buried in Boston)
by Robert McGwier 14 Feb '07

14 Feb '07

(Repeated from earlier since I did not see a return note) I regret very much not being with you tonight. I am in Boston trying to not get snowed in with Eric Blossom and others taking Cell processor training from Mercury. We left dinner long after the TS started because we left work long after the TS started! The Cell processor is a fascinating thing and has the potential to be a really disruptive technology but it is tedious to program. 73's Bob N4HY -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "Taking fun as simply fun and earnestness in earnest shows how thoroughly thou none of the two discernest." - Piet Hine

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Mail
by Dick Jansson-rr 14 Feb '07

14 Feb '07

Lately I have not been receiving Eagle email, owing to shifts in addresses that I was assured did not make for problems. For the moment, please add kd1k(a)amsat.org to your submissions to Eagle mail. Thanks. Dick Jansson, KD1K (ex: WD4FAB) kd1k(a)amsat.org ---------------------------

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Re: 70 cm Receiver layout
by John B. Stephensen 14 Feb '07

14 Feb '07

I've added a paragraph to the U-band receiver page in EaglePedia that describes the PCB layout rules and the board materials. 73, John KD6OZH

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Regrets
by Robert McGwier 14 Feb '07

14 Feb '07

I regret very much not being with you tonight. I am in Boston trying to not get snowed in with Eric Blossom and others taking Cell processor training from Mercury. We left dinner long after the TS started because we left work long after the TS started! The Cell processor is a fascinating thing and has the potential to be a really disruptive technology but it is tedious to program. 73's Bob N4HY -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "Taking fun as simply fun and earnestness in earnest shows how thoroughly thou none of the two discernest." - Piet Hine

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