Terrestrial QRM to FM satellites
Today on passes of both SO-50 and AO-27, there were terrestrial QSOs going on. It was especially bad on AO-27 with a few people clearly unable to get through due to the strength of the QRM. It almost sounded like there was a repeater setup on 145.850 with Roger beeps happening. So, what is the "proper" thing to do in situations like this?
Ignore it and talk to anyone who can overpower them?
Stay off the air and hope you can hear callsigns that you can ask carefully to QSY?
Something else?
I'm pretty new to this stuff, and I'd like to do the right thing.
Bob
You sure this wasn't the Mexican taxi stuff that normally plagues the satellite on the southern half of the passes?
73 de Pat --- KA9SCF. Amsat #35741
On 9/19/07, Bob Stewart [email protected] wrote:
Today on passes of both SO-50 and AO-27, there were terrestrial QSOs going on. It was especially bad on AO-27 with a few people clearly unable to get through due to the strength of the QRM. It almost sounded like there was a repeater setup on 145.850 with Roger beeps happening. So, what is the "proper" thing to do in situations like this?
I didn't know about any Mexican taxis. It's possible on SO-50 I suppose, but AO-27 was almost directly over the Chicago/ South Bend area, and their signals were Q5 and blocking a number of the regulars out.
Bob
--- Patrick Green [email protected] wrote:
You sure this wasn't the Mexican taxi stuff that normally plagues the satellite on the southern half of the passes?
73 de Pat --- KA9SCF. Amsat #35741
On 9/19/07, Bob Stewart [email protected] wrote:
Today on passes of both SO-50 and AO-27, there were terrestrial QSOs going on. It was especially bad on AO-27 with a few people clearly unable to get through due to the strength of the QRM. It almost sounded like there was a repeater setup on 145.850 with Roger beeps happening. So, what is the "proper" thing to do in situations like this?
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
--- Bob Stewart [email protected] wrote:
Today on passes of both SO-50 and AO-27, there were terrestrial QSOs going on. It was especially bad on AO-27 with a few people clearly unable to get through due to the strength of the QRM. It almost sounded like there was a repeater setup on 145.850 with Roger beeps happening.
I know the use of Roger Beeps isn't the usual current practice for Radio Amateurs, at least in IARU Region 1, so it maybe that it's unlicenced operation such as extended range wireless phones etc. There seem to be a number of those in use in the northern part of the Russian Federation.
Reports of interference in Amateur Primary allocations (2m, 10m, 15m) clearly need to be co-ordinated. Can somebody comment on the correct channels (email address) to pass reports of this nature to ?
Instances like this show why it is important that, where power considerations permit, Amateur Satellites do not use CTCSS tones for access, since we need to know what interference is occuring in various parts of the world.
73 Trevor M5AKA
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Hi Trevor,
Well at least for Region 1 I can own up to being a conduit for complaints about non amateur QRM in the 2 metre satellite band into the IARU Region 1 Monitoring System. http://www.iarums-r1.org/ They are very active on the HF bands but I have to admit to not having been able to be very busy in respect to the satellite bands. So if any Region 1 active satellite user would like to take on the role please contact me offline.
Generally they have been very supportive as they understand that whereas problems on VHF/UHF are usually local/national issues, this is not the case when interference occurs to satellite uplinks.
In relation to Region 2 - this is the link http://www.iaruregion2.org/
and for Region 3 http://www.jarl.or.jp/iaru-r3/ms/
It would be sensible to also contact your national MS co-ordinator (if there is one in your country) at the same time of course!
cheers
Graham G3VZV
Reports of interference in Amateur Primary allocations (2m, 10m, 15m) clearly need to be co-ordinated. Can somebody comment on the correct channels (email address) to pass reports of this nature to ?
Hi Bob!
Today on passes of both SO-50 and AO-27, there were terrestrial QSOs going on. It was especially bad on AO-27 with a few people clearly unable to get through due to the strength of the QRM. It almost sounded like there was a repeater setup on 145.850 with Roger beeps happening. So, what is the "proper" thing to do in situations like this?
Ignore it and talk to anyone who can overpower them?
Stay off the air and hope you can hear callsigns that you can ask carefully to QSY?
Something else?
AO-27 regularly picks up non-ham transmissions from Central America (two-way radio and long-range cordless telephone conversations), and lately I've heard what sounds like hams chatting on 145.850 MHz simplex not realizing they are on a satellite uplink. Without the PL tone, SO-50 won't retransmit the QRM, but the QRM sometimes overpowers any legitimate transmissions up to the satellites. Up to now, it seems like AO-51 has been free of the non-ham QRM.
In the past, the non-ham stuff from Mexico had been identified and - with lots of pressure - the Mexican authorities forced the taxis and Red Cross ambulances to move their radios to other frequencies. Unfortunately, some of the new frequencies were somewhere else in the 2m band, but at least the satellite uplinks were free from those QRM sources. It took a lot of work by some Mexican hams to find the sources of the transmissions, sending the documentation to the Mexican "FCC", along with complaints from outside Mexico showing the international impact of these illegal transmissions before any action was taken.
What should you do? If possible, record the passes that you work. You never know what you might hear, and the recording might be useful for someone trying to determine the source of the QRM. Generally, I just try to work the satellite despite the QRM. With an HT, I might not get through all the time, but I'll still try. If the QRM is from two hams chatting on the satellite uplink simplex, they are not affected by your transmissions up to the satellite unless they are close to your location. If it's from Central America or Mexico, the problem generally goes away on passes where the satellites are moving from south to north - moving away from the QRM.
If you hear callsigns coming through the satellite from those chatting on 2m simplex, and if you can find an e-mail address for those stations, send them a note mentioning you heard them through a satellite and politely suggesting they use another frequency. If you have a recording of the pass, send a copy to them to show what you heard. Invite them to try working the satellite, since they obviously have stations that are able to transmit to the satellite based on what you heard.
Good luck and 73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/
Hi Bob!
Today on passes of both SO-50 and AO-27, there were terrestrial QSOs going on. It was especially bad on AO-27 with a few people clearly unable to get through due to the strength of the QRM. It almost sounded like there was a repeater setup on 145.850 with Roger beeps happening. So, what is the "proper" thing to do in situations like this?
Ignore it and talk to anyone who can overpower them?
Stay off the air and hope you can hear callsigns that you can ask carefully to QSY?
Something else?
AO-27 regularly picks up non-ham transmissions from Central America (two-way radio and long-range cordless telephone conversations), and lately I've heard what sounds like hams chatting on 145.850 MHz simplex not realizing they are on a satellite uplink. Without the PL tone, SO-50 won't retransmit the QRM, but the QRM sometimes overpowers any legitimate transmissions up to the satellites. Up to now, it seems like AO-51 has been free of the non-ham QRM.
In the past, the non-ham stuff from Mexico had been identified and - with lots of pressure - the Mexican authorities forced the taxis and Red Cross ambulances to move their radios to other frequencies. Unfortunately, some of the new frequencies were somewhere else in the 2m band, but at least the satellite uplinks were free from those QRM sources. It took a lot of work by some Mexican hams to find the sources of the transmissions, sending the documentation to the Mexican "FCC", along with complaints from outside Mexico showing the international impact of these illegal transmissions before any action was taken.
What should you do? If possible, record the passes that you work. You never know what you might hear, and the recording might be useful for someone trying to determine the source of the QRM. Generally, I just try to work the satellite despite the QRM. With an HT, I might not get through all the time, but I'll still try. If the QRM is from two hams chatting on the satellite uplink simplex, they are not affected by your transmissions up to the satellite unless they are close to your location. If it's from Central America or Mexico, the problem generally goes away on passes where the satellites are moving from south to north - moving away from the QRM.
If you hear callsigns coming through the satellite from those chatting on 2m simplex, and if you can find an e-mail address for those stations, send them a note mentioning you heard them through a satellite and politely suggesting they use another frequency. If you have a recording of the pass, send a copy to them to show what you heard. Invite them to try working the satellite, since they obviously have stations that are able to transmit to the satellite based on what you heard.
Good luck and 73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/
Quoting "Patrick STODDARD (WD9EWK/VA7EWK)" [email protected]:
Hi Bob!
Today on passes of both SO-50 and AO-27, there were terrestrial QSOs going on. It was especially bad on AO-27 with a few people clearly unable to get through due to the strength of the QRM. It almost sounded like there was a repeater setup on 145.850 with Roger beeps happening. So, what is the "proper" thing to do in situations like this?
Once I started hearing this QRM while listening to AO-27, I recorded the tail-end of the 20:00Z pass. Interested persons may download a mp3 file at http://heml.mta.ca/Amsat/ (There is no promise that this link will be in place for a long time.)
Besides the beeps and long periods of carrier-induced silence, there are some conversational snippets which seem to me from native English speakers. One of the amateurs on the bird suggested the QRM comes from a pager, and I labeled the file as such, but I don't mean to suggest that this identification is secure.
73, Bruce VE9QRP
It seems that we have been down this road before......
The short data burst is not paging. The 'squawk' that seems to be at the end of the 'offenders' individual transmissions in the first part of the clip is recognizable to me. It is 1200 baud, and from the sound/duration it is Motorola MDC1200 coding. The MDC1200 is used for ID and status on public safety and other systems. Several hams in my area have taken to using the Motorola radios with the MDC1200 system to ID and contact each other (selective calling, status, emergency, etc.). It is not likely that it would give us much info to go on, if we could decode it. The MDC 1200 system uses hex number data, it is not ASCII. The data, when decoded on another radio will be a 4 digit number. There is a short write up (and sound samples) on: http://en.wikipedia.org/wiki/MDC-1200
Another possibility is that someone has established a simplex Echolink system on the uplink. That may be why some have reported a CW id, and the carrier hanging on for longer than a normal simplex transmission.
Perhaps someone with AMSAT could contact the ARRL Official Observer coordinator. They have been known to send out requests for the OO corps to listen for specific interference problems. This might be important enough to get all ears listening. I don't hear it here.
73 Ernie W8EH
Bruce Robertson wrote:
Once I started hearing this QRM while listening to AO-27, I recorded the tail-end of the 20:00Z pass. Interested persons may download a mp3 file at http://heml.mta.ca/Amsat/ (There is no promise that this link will be in place for a long time.)
Besides the beeps and long periods of carrier-induced silence, there are some conversational snippets which seem to me from native English speakers. One of the amateurs on the bird suggested the QRM comes from a pager, and I labeled the file as such, but I don't mean to suggest that this identification is secure.
Does anyone have a program that can decode the digital ID's? Only one portion in the center of the mp3 sounded like a traditional pager but I think it might be just a "dual." I cleaned it up with Cool Edit Pro and the accents sound southwestern to me but then I haven't been everywhere yet ;-)
Roger WA1KAT
----- Original Message ----- From: "Bruce Robertson" [email protected] To: [email protected] Cc: [email protected] Sent: Thursday, September 20, 2007 8:54 PM Subject: [amsat-bb] Re: Terrestrial QRM to FM satellites
Quoting "Patrick STODDARD (WD9EWK/VA7EWK)" [email protected]:
Hi Bob!
Today on passes of both SO-50 and AO-27, there were terrestrial QSOs going on. It was especially bad on AO-27 with a few people clearly unable to get through due to the strength of the QRM. It almost sounded like there was a repeater setup on 145.850 with Roger beeps happening. So, what is the "proper" thing to do in situations like this?
Once I started hearing this QRM while listening to AO-27, I recorded the tail-end of the 20:00Z pass. Interested persons may download a mp3 file at http://heml.mta.ca/Amsat/ (There is no promise that this link will be in place for a long time.)
Besides the beeps and long periods of carrier-induced silence, there are some conversational snippets which seem to me from native English
speakers.
One of the amateurs on the bird suggested the QRM comes from a pager, and
I
labeled the file as such, but I don't mean to suggest that this identification is secure.
73, Bruce VE9QRP _______________________________________________ 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
It seems that we have been down this road before......
The short data burst is not paging. The 'squawk' that seems to be at the end of the 'offenders' individual transmissions in the first part of the clip is recognizable to me. It is 1200 baud, and from the sound/duration it is Motorola MDC1200 coding. The MDC1200 is used for ID and status on public safety and other systems. Several hams in my area have taken to using the Motorola radios with the MDC1200 system to ID and contact each other (selective calling, status, emergency, etc.). It is not likely that it would give us much info to go on, if we could decode it. The MDC 1200 system uses hex number data, it is not ASCII. The data, when decoded on another radio will be a 4 digit number. There is a short write up (and sound samples) on: http://en.wikipedia.org/wiki/MDC-1200
Another possibility is that someone has established a simplex Echolink system on the uplink. That may be why some have reported a CW id, and the carrier hanging on for longer than a normal simplex transmission.
Perhaps someone with AMSAT could contact the ARRL Official Observer coordinator. They have been known to send out requests for the OO corps to listen for specific interference problems. This might be important enough to get all ears listening. I don't hear it here.
73 Ernie W8EH
Bruce Robertson wrote:
Once I started hearing this QRM while listening to AO-27, I recorded the tail-end of the 20:00Z pass. Interested persons may download a mp3 file at http://heml.mta.ca/Amsat/ (There is no promise that this link will be in place for a long time.)
Besides the beeps and long periods of carrier-induced silence, there are some conversational snippets which seem to me from native English speakers. One of the amateurs on the bird suggested the QRM comes from a pager, and I labeled the file as such, but I don't mean to suggest that this identification is secure.
participants (8)
-
Bob Stewart -
Bruce Robertson -
Ernie Howard -
Graham Shirville -
Patrick Green -
Patrick STODDARD (WD9EWK/VA7EWK) -
Roger Kolakowski -
Trevor