[amsat-bb] Re: Response to my request of information about EduSat from GAUSS team in Rome: Re: [CubeSat] Edusat operative or failure
On 30/08/11 21:13, don wrote: Ok, So it's not an amateur sat. It is also not an amateur "experiment",so why is it using amateur frequencies? I have read and reread the regulations governing the use of amateur frequencies and all I can find is a vague definition to the effect that the operators should be licensed amateur operators! What is so different that the amateur satellite "service" can use any non disclosed frequencies and modulation techniques to any other "secret communication" systems that are expressly prohibited by the universal amateur regulations? Just my annoyed response, Don ZL1THO. Hi Dom, The 70 cm ops may well be perfectly legal. The 2 m use perhaps not. In Region three, 70 cm is shared. It's not exclusively ours. It's not even primarily ours, Hams are secondary users. As well as radiolocation, it's available for Earth Exploration Satellites. Perhaps that is what this satellite qualifies as. You can read about this on the RSM website here: http://www.rsm.govt.nz/cms/tools-and-services/publications/public-information-brochures-pibs/pib-21-table-of-radio-spectrum-usage-in-new-zealand/2-3-new-zealand-table-of-allocation-1/2-3-5-uhf-band-300-3000mhz Encryption is permitted (via an exemption) in Amateur bands if the signal is for satellite control. Sil ___ Sent via AMSAT-BB@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
[amsat-bb] Re: NASA 2 Line via mail?
Domenico Yes, what you say is true. But that is not what Rich asked in his email. He asked this: * Which NASA office did these originate from? * When did this service begin/end? * Could requests be made for any unclassified object in orbit, as long as the designator was known? I am sure Rich knows where he can find keps now. That wasn't what he wanted to know. I thought it was an interesting story. Sil ZL2CIA ___ Sent via amsat...@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
[amsat-bb] Re: New Cubesat - the Ultimate Fox Hunt - kinda OT now, sorry
Graham, Cool. But still no cigar as far as Joe's question. So.. the broad flat shape generates more compressive heating, than the more pointy nose of the launch vehicle. But... the launch vehicle is still going to generate a great deal of heat through the same process if it is doing the same hypersonic speed at the same altitude. So is it? Sil Graham Shirville wrote: > According to the "Apollo 11 Owner's Workshop Manual" recently > published by Haynes here in the UK > page 71 > > "Atmospheric Heating" > Frictional heating was not just a problem during re-entry. During the > acceleration after launch through the thicker, lower atmosphere, the > apex of the command module would also be exposed to aerodynamic > heating and needed protection by an additional cork and fibreglass > shroud attached to the launch escape tower. > The far more intense re-entry heating is often mistakenly thought to > be something to do with friction with the passing air. In fact the > extra heating during re-entry is more comparable to the heat that > builds up in a valve in a bicycle pump as air is compressed into a > tyre. When any gas is compressed the amount of energy that it holds in > a given volume rises. When the air in front of a blunt hypersonic > craft cannot move aside fast enough it becomes compressed and so heats > up for the same reason. > During re-entry the speeds, and therefore the compression, are so > great that the temperature can easily rise into the thousands of > degrees, approaching the same sort of temperature as on the surface of > the sun (5,500C) . The advantage of the blunt shape has in this > process over a more streamlined form is that by creating this > compressed layer of air ahead of it, the main part of the craft is > separated from the hottest and most damaging heat." > > So all we need is a cubesat containing a deorbit propulsion system so > that the landing point can be carefully selected, which has inside it, > a miniature Apollo shaped capsule made of titanium with a heat shield > on the blunt end and which has ceramic panels so that the inbuilt GPS > can receive and the VHF or UHF or S band transmitter can transmit.:) > > 73 > > Graham G3VZV > > PS The Haynes Manual is available from the RSGB ___ Sent via amsat...@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
[amsat-bb] Re: New Cubesat - the Ultimate Fox Hunt
Joe, I found a graph here http://www.hq.nasa.gov/pao/History/conghand/possibil.htm that shows speed versus altitude (in obscure units, but never mind) for both sounding rockets and orbital satellite launches (into a circular orbit) It's not in the greatest detail. Now to find the same data for the way down. Sil ZL2CIA ___ Sent via amsat...@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
[amsat-bb] Re: New Cubesat - the Ultimate Fox Hunt
Sil - ZL2CIA wrote: > Bob Bruninga wrote: > > >> The difference is that going up, you are going slowly in the higher density >> atmosphere which is continually lessening as you go up letting you go faster >> and faster with less and less friction. THus, no multiplying build up of >> friction. >> >> >> > Bob, > > I hesitate to say this, but I'm almost certain that re-entry heating is > not caused by friction (well may be 10%). Most reliable sources, NASA > included, attribute re-entry heating to shock wave compression of the > air in front of the descending craft. > > Sil > ZL2CIA > Wikipeadia reckon 80% of the heating experienced by a re-entering orbiter (shuttle) is the result of compression, leaving 20% to friction. The 90% figure might be more correctly applied to the Apollo re-entry vehicle. It was a very different shape. Some highspeed vehicles did experience severe heating, notably the amazing X-15 craft. The question is a good one, but the answer has needs to consider far more than frictional heating, since that accounts for only a small part of the energy that is converted to heat during re-entry. I have no idea what the equivalent ratio is on the way up, but it is a delightful puzzle. Thanks Joe. Sil ZL2CIA Sil ___ Sent via amsat...@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
[amsat-bb] Re: New Cubesat - the Ultimate Fox Hunt
Bob Bruninga wrote: > The difference is that going up, you are going slowly in the higher density > atmosphere which is continually lessening as you go up letting you go faster > and faster with less and less friction. THus, no multiplying build up of > friction. > > Bob, I hesitate to say this, but I'm almost certain that re-entry heating is not caused by friction (well may be 10%). Most reliable sources, NASA included, attribute re-entry heating to shock wave compression of the air in front of the descending craft. Sil ZL2CIA ___ Sent via amsat...@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
[amsat-bb] Re: Here's another set.
Hi The Keps Nigel Gunn G8IFF /W8IFF posted for Dragonsat seem to give me the best match for POLLUX-1 Is there any particular place I should send the captured Telemetry? Sil ZL2CIA ___ Sent via amsat...@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
[amsat-bb] Re: USB-to-Serial adapter
Norman, My experience is that some of the really cheap ones don't have proper level shifters on the RS232 (V.24) side. Instead, they use "power stealing" from the RS232 line. This doesn't always work. It certainly won't work if the TTL <--> RS232 level shifter you use to connect to the rig also tries to "power steal" There is another option. I see RS232<-->USB converters sold here that use 3.3 and zero volt levels, rather that -12 and +12 volt on the RS232 side. Since you are building you own interface, you could use these instead. From memory, the FT736R uses inverted signals on the TTL side, so one TTL inverter chip would probably be all you needed (oh, plus a 7805 or similar) Sil ZL2CIA Norman W Osborne VE3CJE wrote: > Hello everyone, > > I am building an interface for a 736r doppler control and I will be needing > > a USB-to-Serial adapter. > > Looking on ebay I see many choices and prices. > > Have any of you bought any of these adapters?? > > > > Any suggestions appreciated. > > > > 73, > > Norman. > > > > > > ___ > Sent via amsat...@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 > > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.5.392 / Virus Database: 270.13.38/2274 - Release Date: 07/31/09 > 05:58:00 > > ___ Sent via amsat...@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
[amsat-bb] Re: More Telem
Came home, went up into the shack, turned the rig on and captured one packet within seconds. Time is NZST (UT + 12) Fm POLLUX-1 To CQ Via TELEM [23:11:07] SYST 150447 0 0 33 0 fffe 0fd0 fffe 0fc8 fffe 0f80 fffe 0b90 fffe 0b60 0158 08d6 0fba 003a Sil ZL2CIA ___ Sent via amsat...@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
[amsat-bb] Full duplex radios
> Nigel, > > > Yes, of course, that's true. A single band repeater is a full duplex radio. > > I don't think their are any Ham radios that operate full duplex in a > single band. Of course, I could easily be wrong. Do you know of any? > > > > Sil "There", not "their" - sheesh Sil ___ Sent via amsat...@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
