I've just come across the following interesting references on space ref to what seems to be a VHF telemetry channel (bio/medical monitoring?)
"...including VHF/voice & biomedical electrode belt and *telemetry hookups via the BSS (later by the wireless in-suit Tranzit-B radio telemetry system) for vital signs and equipment monitoring".
http://www.spaceref.com/news/viewsr.html?pid=30763
and:
" [The suited run requires wireless Tranzit-B suit radio telemetry on both semisets (activated: 2:56am) and temporary deactivation of the Russian VHF channel 1 (Very High Frequency, Russian: UKV1, for ultra-shortwave) to avoid interference from extraneous radio stations to the Orlans while over Russian ground stations (RGS, DO 3/4). All EVA preps were monitored by the ground via audio, the reason for the early morning time of the training run. Tranzit-B TM was turned off at ~3:10am EST.]"
http://www.hq.nasa.gov/osf/iss_reports/reports2008/12-19-2008.htm
My questions are: what is the TRANZIT-B TM system, how close is it to the 2m channels, what is the TLM data modulation and breakdown?
73 de andy G0SFJ
The Russians have a few transmitters in the VHF band. I am not at liberty to release the exact frequencies.
One of the commercial radios on ISS is a FM Repeater. The downlink is just below the amateur radio 2-meter band and the uplink is in the aircraft band.
Once a month or so they leave the VHF-1 radio running constantly to test the ground stations ability to access this system in case of emergency. If the ISS ever tumbles, it will loose satellite lock and will have to rely on VHF communications line-of-site links until stable flight is reestablished. The Mir Space Station tumbled on several occasions.
Sometimes you can hear VHF-1 while ISS is passing over the USA. When the repeater mode is active you can hear American aircraft signals being re-transmitted over the ISS commercial repeater.
It seems that there is no interested in making the Russian ISS repeater input channel a clear channel in the USA.
When VHF-1 was active on Mir, it would immediately de-sense the Kenwood TM-733 and the TM-V7A. To correct this problem I installed a custom built filter from DCI to notch out the offending VHF-1 transmission. I have not been able to confirm if ISS has the same issues.
73 Miles WF1F www.marexmg.org
--- On Mon, 3/16/09, andy thomas [email protected] wrote:
From: andy thomas [email protected] Subject: [amsat-bb] Tranzit-B telemetry system on ISS To: "amsat" [email protected] Date: Monday, March 16, 2009, 6:08 PM I've just come across the following interesting references on space ref to what seems to be a VHF telemetry channel (bio/medical monitoring?)
"...including VHF/voice & biomedical electrode belt and *telemetry hookups via the BSS (later by the wireless in-suit Tranzit-B radio telemetry system) for vital signs and equipment monitoring".
http://www.spaceref.com/news/viewsr.html?pid=30763
and:
" [The suited run requires wireless Tranzit-B suit radio telemetry on both semisets (activated: 2:56am) and temporary deactivation of the Russian VHF channel 1 (Very High Frequency, Russian: UKV1, for ultra-shortwave) to avoid interference from extraneous radio stations to the Orlans while over Russian ground stations (RGS, DO 3/4). All EVA preps were monitored by the ground via audio, the reason for the early morning time of the training run. Tranzit-B TM was turned off at ~3:10am EST.]"
http://www.hq.nasa.gov/osf/iss_reports/reports2008/12-19-2008.htm
My questions are: what is the TRANZIT-B TM system, how close is it to the 2m channels, what is the TLM data modulation and breakdown?
73 de andy G0SFJ
Sent via [email protected]. 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
The Russians have a few transmitters in the VHF band. I am not at liberty to release the exact frequencies.
Sheesh. If anyone is curious, look about halfway down this page: http://www.issfanclub.com/frequencies
73, Drew KO4MA
How are the "American aircraft signals" which are all AM, being rebroadcast in any intelligible way by an FM receiver?
The only aircraft that MIGHT transmit with FM, are military aircraft. And rarely in the clear or without frequency-hopping spread spectrum technology involved. (And that's not really FM, so to speak -- nor copyable through the repeater you're describing.)
I smell something wrong here with your information, or there's more to the story.
Nate WY0X
-----Original Message-----
Sometimes you can hear VHF-1 while ISS is passing over the USA. When the repeater mode is active you can hear American aircraft signals being re-transmitted over the ISS commercial repeater.
Aircraft transmissions are AM to allow detection a weaker signal that may come from a distressed aircraft. A carrier 30 dB lower will still produce a whistle allowing the controller to ask the other aircraft to stand by to copy the weaker signal.
Art, KC6UQH
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Nate Duehr Sent: Monday, March 16, 2009 5:27 PM To: 'amsat' Subject: [amsat-bb] Re: Tranzit-B telemetry system on ISS
How are the "American aircraft signals" which are all AM, being rebroadcast in any intelligible way by an FM receiver?
The only aircraft that MIGHT transmit with FM, are military aircraft. And rarely in the clear or without frequency-hopping spread spectrum technology involved. (And that's not really FM, so to speak -- nor copyable through the repeater you're describing.)
I smell something wrong here with your information, or there's more to the story.
Nate WY0X
-----Original Message-----
Sometimes you can hear VHF-1 while ISS is passing over the USA. When the repeater mode is active you can hear American aircraft signals being re-transmitted over the ISS commercial repeater.
_______________________________________________ Sent via [email protected]. 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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On Mar 16, 2009, at 6:27 PM, Nate Duehr wrote:
How are the "American aircraft signals" which are all AM, being rebroadcast in any intelligible way by an FM receiver?
You know, you didn't say (and probably can't) what kind of receiver it's using, actually. I assumed FM in, FM out.
I smell something wrong here with your information, or there's more to the story.
I was careful to say this, but got one very professional and two nasty comments off-list who thought I was attacking the original poster. I wasn't. The professional comment came (not too surprisingly) from someone elected to AMSAT leadership, showing excellent taste and restraint. Thanks, you know who you are.
Just saying it smelled fishy to me -- assuming an FM receiver. No harm meant by it. The typical FCC TSO'ed AM aircraft transmitter is 5W PEP, some are 10W PEP. 5W PEP AM to an FM receiver to be well detected at ISS's range is certainly do-able, but it wouldn't sound very good, I'd think. Don't know. All depends on the receiver quality, of course... a bunch of stuff.
The MUCH more interesting tid-bit that was somewhat hidden in the rest of the non-AMSAT info in the message was that there's a DCI filter on the front-end of the Kenwood? Did I read that correctly?
That made me wonder a new question: What's the measured insertion loss on it?
It would make for more interesting data for accurate link-budget analysis/calculations for talking to the ARISS station. Would be interesting to see if the rig meets the published Kenwood specs, minus the antenna "gain" and filtering by altering power from this end and seeing if the numbers match up in the real world.
Is the DCI filter being in-line widely known? I've never seen it on any of the ARISS documentation I've read, but it might have been there somewhere. Maybe I missed it.
That seemed to be the only AMSAT-related part of that original posting... the fact that there's other "commercial" transmitters and receivers on board, seemed like a "given" to me. It also seemed obvious that filtering and mitigation of effects from one system to another has to be done, like on all spacecraft or other multi- frequency RF systems crammed into a relatively small space.
-- Nate Duehr, WY0X [email protected]
On Mar 16, 2009, at 11:57 PM, Nate Duehr wrote:
harm meant by it. The typical FCC TSO'ed AM aircraft transmitter is
Bah... the FAA TSO's Aviation gear. Too late at night... no brain cells firing anymore... (sigh).
-- Nate Duehr, WY0X [email protected]
I believe DCI specs their filters on their website. I have a 6-pole 144-MHz cavity filter that runs about 0.1 dB insertion loss, though I believe they spec it as 0.2 dB. There are several models so one would need the model number. I use mine between my 1st preamp and 2nd preamp in my 2m-eme station to help isolate out of band RF overload of the receiver. It is rated for 200w so can be used for Tx filtering.
73, Ed - KL7UW
At 09:57 PM 3/16/2009, Nate Duehr wrote:
On Mar 16, 2009, at 6:27 PM, Nate Duehr wrote:
How are the "American aircraft signals" which are all AM, being rebroadcast in any intelligible way by an FM receiver?
You know, you didn't say (and probably can't) what kind of receiver it's using, actually. I assumed FM in, FM out.
I smell something wrong here with your information, or there's more to the story.
I was careful to say this, but got one very professional and two nasty comments off-list who thought I was attacking the original poster. I wasn't. The professional comment came (not too surprisingly) from someone elected to AMSAT leadership, showing excellent taste and restraint. Thanks, you know who you are.
Just saying it smelled fishy to me -- assuming an FM receiver. No harm meant by it. The typical FCC TSO'ed AM aircraft transmitter is 5W PEP, some are 10W PEP. 5W PEP AM to an FM receiver to be well detected at ISS's range is certainly do-able, but it wouldn't sound very good, I'd think. Don't know. All depends on the receiver quality, of course... a bunch of stuff.
The MUCH more interesting tid-bit that was somewhat hidden in the rest of the non-AMSAT info in the message was that there's a DCI filter on the front-end of the Kenwood? Did I read that correctly?
That made me wonder a new question: What's the measured insertion loss on it?
It would make for more interesting data for accurate link-budget analysis/calculations for talking to the ARISS station. Would be interesting to see if the rig meets the published Kenwood specs, minus the antenna "gain" and filtering by altering power from this end and seeing if the numbers match up in the real world.
Is the DCI filter being in-line widely known? I've never seen it on any of the ARISS documentation I've read, but it might have been there somewhere. Maybe I missed it.
That seemed to be the only AMSAT-related part of that original posting... the fact that there's other "commercial" transmitters and receivers on board, seemed like a "given" to me. It also seemed obvious that filtering and mitigation of effects from one system to another has to be done, like on all spacecraft or other multi- frequency RF systems crammed into a relatively small space.
-- Nate Duehr, WY0X [email protected]
Sent via [email protected]. 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
On Mon, 2009-03-16 at 23:57 -0600, Nate Duehr wrote:
Just saying it smelled fishy to me -- assuming an FM receiver. No harm meant by it. The typical FCC TSO'ed AM aircraft transmitter is 5W PEP, some are 10W PEP. 5W PEP AM to an FM receiver to be well detected at ISS's range is certainly do-able, but it wouldn't sound very good, I'd think. Don't know. All depends on the receiver quality, of course... a bunch of stuff.
Further to my earlier message, a quick experiment has shown that my Kenwood TH-F7E (same one I picked the Edinburgh guys up with) gives intelligible but not brilliant audio from aircraft when it's set to FM. This may be down to the radio. I can post a couple of recordings, if you like.
Gordon
Hi all:
I guess I should have used the word “Transponder” rather than the word “Repeater” in my last memo. The device on ISS appears to act more like a Transponder, rather than a true FM repeater. The Transponder will repeat any signal it hears on the input and retransmit that signal on the output. At the end of this memo I attached an email from the person that provided the recording made last year.
[SCPC-FDM,SAT DX] 143.625 ODD CommsTuesday, July 8, 2008 11:12 PM From: "Jody" Add sender to Contacts To: [email protected]
This morning, sometime before 12 EST time local here I copied some strange comms from the ISS frequency of 143.625. The modulation mode was WFM. Other known ISS frequencies were active with data transmissions at the same time. Attached is a link to a recording I made of the 143.625 Frequency. You can tell at the start of the recording I was tuning in the Narrow FM mode, 5.5Khz bandwidth, after switching to wide FM mode on my Icom R8500 I was able to copy the comms. For some reason the crew was retransmitting aircraft comms. In the clip you hear a center controller and some other aircraft. One aircraft heard in the clip was Cessna 38 Uniform. it appears that aircraft was based in Colorado from a registration lookup. Also the center controller made references to Memphis center. It sounds very much like someone was tuning around the airbands and it was getting retransmitted. I was told by one that it could been a possible Comm test for a upcoming EVA. Take a listen and see if you can pull anything more from the recording. I was using a Icom R8500 and a discone antenna. No chance of intermod. Poor signal quality due to the antenna not being resonant, it’s was 225-400Mhz mil discone being used.
Link to audio: http://www.savefile.com/files/1655618
One aircraft in recording: http://registry.faa.gov/aircraftinquiry/NNumSQL.asp?NNumbertxt=38U&cmndf...
Jody North Georgia
***********
The DCI filter was a custom Job for Space Station Mir.
Picture of Filter http://www.flickr.com/photos/36403622@N06/
The problem: When the VHF-1 Transmitter was active, the Amateur radio station would go deaf. The Russian crew used the VHF-1 transmitter frequently over the USA during joint American missions. This would manifest its self by seeing the Kantronics KPC-9612 packet system send out a consecutive series of 7 Retries to the person that was last logged in. No other packet would be seen coming down. It was just like someone was logged in and then the receiver was turned off. If you switched over to the VHF-1 frequency you could hear a strong down link signal and voice.
I tested this theory again with a phone patch to Jerry Linenger and his brother in Detroit. The first few seconds of the phone patch went good via the Kenwood TM-733, then Jerry could not hear my signal any more. I quickly checked the VHF-1 channel and found the Mir crew members talking to Moscow via the Houston VHF-1 ground station. I was finally able to punch through the interference for a few seconds while Mir was directly over my house. I was using a Yaesu FT-736R, M2-CP22 antenna, AZ/EL rotor and EIRP 2-5 kW.
I was finally able to convince ARISS the filter was a needed project and they agreed. ARISS generate the appropriate paper work and Russia flew the filter to Mir in the spring on 1998, just in time for Andy’s mission.
The Solution: Ralph at DCI used one of this stock 4 cavity filters and added a 5th cavity. The extra cavity contained a Notch filter aimed at the frequency of VHF-1. The Notch filter provided an additional 20-25 dB of attenuation. With the new filter the Kenwood radios could be used to receive down to the 145 MHz range, while the VHF-1 transmitter was active.
At the present time ARISS does not believe their is any noticeable de-sensing problems with the Amateur Radio station on ISS, so the DCI project for ISS is on hold until we have proven there is a need.
Special thanks to Jody at the Yahoo SCPC-FDM,SAT DX group for providing the recordings from ISS
And thanks to Kenwood for building radios that can survive for years inside a manned space station.
73 Miles WF1F Marex, (4 project in flight an growing)
On Mar 17, 2009, at 6:09 AM, MM wrote:
Link to audio: http://www.savefile.com/files/1655618
One aircraft in recording: http://registry.faa.gov/aircraftinquiry/NNumSQL.asp?NNumbertxt=38U&cmndf...
Jody North Georgia
Hi Jody,
Interesting recording.
The female voice clearly says, "Calling today, this is Memphis Center?"... a Center controller picking up an aircraft in-flight, probably for VFR "flight following" services, or she just missed a call-up. Standard phraseology. Seems to match the "flight following" thing since then...
The analysis of the tail number is incorrect. Later she talks a couple of times to "Cessna 38U".
Tail numbers on-air are shortened to the last three characters of the tail number, if no conflicting callsigns are on the frequency -- to save airtime. Therefore that's not "N38U" as the full callsign (a glider based out of Boulder, CO as you noted with the FAA registry), but is a Cessna with a tail number ending in 38U, flying somewhere in Memphis Center's controlled airspace.
At one point the flow of the conversation through standard phraseology would indicate that the Cessna or another aircraft she's talking to is at 5500' MSL. Making her a "low-altitude" sector at Memphis, or dual- controlling (transmitting on more than one frequency) multiple sectors, depending on time of day and traffic load.
There's also communications with a King Air, but I need to go get the headphones out to pick that callsign out.
http://microvoltradio.com/ARTCC/KZME.htm
Right at the very end you also hear an aircraft call up "right downwind", likely ISS has moved far enough East that Memphis Center can no longer be heard, and the frequency is re-used by the FAA at a towered airport somewhere further East.
At the very beginning of the recording, it sounds like the receiver is wide enough that it's hearing some other stuff that's not on its center frequency on the West Coast... or wherever the ground track took ISS this particular day and time of this recording.
Thanks for sharing, neat to listen to...
-- Nate Duehr, WY0X [email protected]
No, you misread it. The DCI filter was used on the Mir installation. There is no additional filter on the D700 aboard ISS.
-- Dave, W8AAS
On Mar 17, 2009, at 1:57 AM, Nate Duehr wrote:
The MUCH more interesting tid-bit that was somewhat hidden in the rest of the non-AMSAT info in the message was that there's a DCI filter on the front-end of the Kenwood? Did I read that correctly?
On Mon, 2009-03-16 at 18:27 -0600, Nate Duehr wrote:
How are the "American aircraft signals" which are all AM, being rebroadcast in any intelligible way by an FM receiver?
Uhm, perhaps because FM receivers can usually pick up AM pretty well, if not perfectly?
It took me a while to realise that the slight distortion I was hearing on the infamous Edinburgh 145.800MHz (yes, they trample on the ISS downlink) net was because they were using AM, not FM. It just sounded very slightly off-tune, but no amount of tweaking would bring it in...
Gordon
participants (8)
-
Andrew Glasbrenner -
andy thomas -
Art McBride -
Dave Taylor -
Edward Cole -
Gordon JC Pearce MM3YEQ -
MM -
Nate Duehr