wats@scicom.alphacdc.com (Bruce Watson) (08/27/87)
A recent issue of Monitoring Times lists the frequencies 259.700 and 296.800 MHz as Space Shuttle comm frequencies. The mode is given as AM voice. Does anyone know if these are encryp, thi
mike@ames.UUCP (09/02/87)
In article <1008@scicom.alphacdc.com> wats@scicom.alphacdc.com (Bruce Watson) writes: >296.800 >MHz as Space Shuttle comm frequencies. The mode is given as AM voice. >Does anyone know if these are encrypted? Up through 51L, no encryption has been used, except on the military flights. Many people have monitored the shuttle on simple police scanner type radios. I much rather prefer using my satillite dish though, to copy the NASA video feeds. There you get 24 hr/day mission coverage with all downlink video. Heaven to a space junkie like moi! -- *** mike (powered by M&Ms) smithwick *** "ever felt like life was a game, and someone gave you the wrong instruction book?" [discalimer : nope, I don't work for NASA, I take full blame for my ideas]
stu@splut.UUCP (Stewart Cobb) (09/12/87)
Shuttle space-to-ground communications are primarily conducted via S-band digital signals. There are several channels around 2500 MHz, with several different modes. Voice is digitized and stuffed into the telemetry frames. There are several different formats. This is a very hard signal to pick apart, to recover the voice. There is an auxiliary UHF FM system for voice comm only. It has three channels, and is designed to the parameters of a standard UHF aircraft radio. One channel is the UHF aircraft distress (GUARD) frequency, 243.0 MHz. This was included so that the Shuttle could talk to the normal air traffic control system in emergencies. The UHF voice system is normally set to one of the other two channels, and fed audio in parallel with the S-band. Obviously, the UHF voice cannot be encrypted, so it is turned off during secure flights. I am reluctant to give the frequencies of the other two UHF channels, because I don't know how many squirrels read this group. I trust 95% of you, but one bad apple could screw up a major national asset. Sigh. "Paranoia strikes deep" -- Buffalo Springfield. A side note: You may have wondered (I did) why there's not much first-hand info about the Shuttle on the net. Would you believe that there is not a single Internet connection on site at Johnson Space Center? As far as I know, there are no USENET connections, either. JSC is not as far out on the leading edge as you may have been led to believe. We are working on the problem, however. Cheers! Stewart Cobb, N5JXE << Insert the usual disclaimer >>
omega@ut-ngp.UUCP (Omega.Mosley`) (09/15/87)
....just out of curiosity, were the few attempts at ham-links to the Shuttle in orbit done in the 2-meter band, or was this also relegated to the rather demised 220 band? OM Disclaimer: 11-meters BACK to the Hams?? Yer KIDDING, right???
karn@faline.bellcore.com (Phil R. Karn) (09/15/87)
> I am reluctant to give the frequencies of the other two UHF channels, > because I don't know how many squirrels read this group. I trust 95% > of you, but one bad apple could screw up a major national asset. Sigh. > "Paranoia strikes deep" -- Buffalo Springfield. The shuttle comm frequencies are public information. From my Rockwell STS-1 press kit, the three UHF AM frequencies are: 296.8 (primary), 259.7 (secondary), and 243.0 Mhz (emergency). The S-band frequencies are: 2287.5 Mhz (PM downlink - primary) 2217.5 Mhz (PM downlink - secondary) 2250.0 Mhz (FM downlink - primary) 2205.0 Mhz (FM downlink - development flight instrumentation) 2106.4 Mhz (PM uplink - primary) 2041.9 Mhz (PM uplink - secondary) 1831.8 Mhz (PM uplink - DoD primary) 1775.7 Mhz (PM uplink - DoD secondary) The links operate in either a high speed or low speed mode: Uplink High speed Low speed voice 2 @ 32 kb 1 @ 24kb command 1 @ 8 kb 1 @ 8 kb total 72 kb 32 kb Downlink voice 2 @ 32 kb 1 @ 32 kb telemetry 1 @ 128 kb 1 @ 64 kb total 192 kb 96 kb As Ron said earlier, the data stream is multiplexed stuff with digital voice and telemetry. However, all of the data formats are also public information. I have a NTIS report on the performance of the communications system during the STS-2 ascent, and in an appendix are complete details on everything you need - frame sync vectors, channel assignments, etc. In addition to the digital data, the PM downlinks repeat a 1.7 Mhz ranging tone. For the non-DoD uplinks, the carrier frequency of the downlink transmitter is phase locked to 240/221 times the uplink frequency, also for tracking. While certainly challenging, this is not outside of the capabilities of a dedicated amateur. The FM downlinks can carry a variety of stuff, e.g., television [probably analog], 128 kb/s real-time engine data or 192 kb/s playbacks of recorded data. Phil
mac@idacrd.UUCP (Bob McGwier) (09/15/87)
in article <6253@ut-ngp.UUCP>, omega@ut-ngp.UUCP (Omega.Mosley`) says: > Xref: idacrd sci.space.shuttle:298 rec.ham-radio:2496 > > > ....just out of curiosity, were the few attempts at ham-links to the Shuttle > in orbit done in the 2-meter band, or was this also relegated to the rather > demised 220 band? > > > > OM > Two meters and FM. We haven't lost 220 Mhz YET. The FCC hasn't ruled and frankly they were dumbfounded at the overwhelming response from the amateur community. Bob .
winter@apple.UUCP (09/16/87)
In article <6253@ut-ngp.UUCP> omega@ut-ngp.UUCP (Omega.Mosley`) writes: >....just out of curiosity, were the few attempts at ham-links to the Shuttle >in orbit done in the 2-meter band, or was this also relegated to the rather >demised 220 band? "Attempts"? "Few attempts"? That'll be news to the hundreds of hams who've talked to the shuttle. Owen Garriott alone made over 350 2-way contacts--and that was just the first of three hams-in-space. Anyway, yes, they were on 2m. (At least mostly--anybody know if DL-1 used other bands?) Patty -- Patty Winter N6BIS (408) 973-2814 M/S 2C, Apple Computer, Inc., 20525 Mariani Ave., Cupertino, CA 95014 {decwrl,nsc,sun,dual}!apple!winter
karn@faline.UUCP (09/16/87)
> ....just out of curiosity, were the few attempts at ham-links to the Shuttle > in orbit done in the 2-meter band, or was this also relegated to the rather > demised 220 band? The Ham-in-Space operation took place under the Amateur Satellite Service rules, not the regular Amateur Service. The former allows the use of only certain sections of certain amateur bands, generally those that are allocated to the amateur service on a worldwide basis. The 220 Mhz amateur band doesn't exist outside of Region 2, so it is not available to the Amateur Satellite Service. Phil
robert@uop.UUCP (09/17/87)
the frequencies are not confidential information, and are available. they have sufficiently protected themselves by the digitization of the S band yacking. the JSC was on the net, at least i thought i read somethings at some times from jsc (as well as jpl)
mike@ames.UUCP (09/19/87)
In article <6253@ut-ngp.UUCP> omega@ut-ngp.UUCP (Omega.Mosley`) writes: >....just out of curiosity, were the few attempts at ham-links to the Shuttle >in orbit done in the 2-meter band, or was this also relegated to the rather >demised 220 band? The two ham-in-space missions (STS-9 and STS-41somethingorother) were both on 2m, partly because the 2m equipment was donated to the project, and partly because they wanted the widest possible coverage. Even common police scanners could've picked them up. Oh, and by the way, the open shuttle frequencies have been published many times so I don't think that the fbi is going to get me for announcing them. If I havn't had a parity error, the main one is 296.8 mhz with an alternate of 253.--error--. OOps gotta go back and check up on that one. -- *** mike (powered by M&Ms) smithwick *** "ever felt like life was a game, and someone gave you the wrong instruction book?" [discalimer : nope, I don't work for NASA, I take full blame for my ideas]
jay@splut.UUCP (Jay Maynard) (09/19/87)
In article <6253@ut-ngp.UUCP>, omega@ut-ngp.UUCP (Omega.Mosley`) writes: > ....just out of curiosity, were the few attempts at ham-links to the Shuttle > in orbit done in the 2-meter band, or was this also relegated to the rather > demised 220 band? The several links to the Shuttle (including the first TV transmission TO a manned spacecraft) were done on 2 meters. As for the 'rather demised' 220 band: (wait one while I put on my President, Texas VHF-FM Society hat on:) OVER MY DEAD BODY! There's much more ham activity on 220 than anyone gives us credit for. Most of the ruckus being raised by the commercials who want to steal this chunk of ham spectrum got their info from the ARRL Repeater Directory. Of course, they didn't realize (or chose to forget) that there's much more to ham radio than FM and repeaters... (Apologies to pure sci.space.suuttle readers. Followups on the 220 grab, please edit the groups: line.) -- Jay Maynard, K5ZC (@WB5BBW)...>splut!< | uucp: hoptoad!academ!uhnix1!splut!jay Never ascribe to malice that which can | or sun!housun!nuchat!--^ be adequately explained by stupidity. | GEnie: JAYMAYNARD CI$: 71036,1603 The opinions herein are shared by neither of my cats, much less anyone else.