Current Channel lineup - SPVM?

[plaws]

I see many things posted claiming to be SPVM channels. Not sure which is the most current. For instance, some show 410.4875 as Ouest 1, others show 410.1125. Another even shows 857.5875 for units at YUL.

Clearly, some of those lists are wrong. I'll make this easy: Is the list at Montreal County, Quebec (QC) Scanner Frequencies and Radio Frequency Reference correct? Are the labels correct (aside from being in English)?

 

[VORTAC]

I see many things posted claiming to be SPVM channels.

Where ?

Do not worry, everything that is written in the database is correct.

 

[plaws]

Where ?

Do not worry, everything that is written in the database is correct.

Not here, obviously. I thought they were using channel numbers like "2-1" and "1-4". Is that no longer the case?

 

[rc1990]

Not here, obviously. I thought they were using channel numbers like "2-1" and "1-4". Is that no longer the case?

Yes they still do : the first number identifies the group of frequencies. For exemple, 1-x are dispatch (OPS) channels, 2-x are investigative (encrypted) channels and 3-x are SWAT channels. When the Montréal page was updated, the group number (1, 2,3) was deleted fron the alpha tags and they were added in the freq table's title.

 

[plaws]

Yes they still do : the first number identifies the group of frequencies. For exemple, 1-x are dispatch (OPS) channels, 2-x are investigative (encrypted) channels and 3-x are SWAT channels. When the Montréal page was updated, the group number (1, 2,3) was deleted fron the alpha tags and they were added in the freq table's title.

Capte. Merci.

So when were the Metro Cops (that weren't actually cops for the longest time) integrated with SPVM? Or is that just some sort of mutual aid channel?

And what's with the 800-MHz channel at YUL?

 

[rc1990]

Capte. Merci.

So when were the Metro Cops (that weren't actually cops for the longest time) integrated with SPVM? Or is that just some sort of mutual aid channel?

And what's with the 800-MHz channel at YUL?

Pas de problème mon ami! For that info you could consult the following websites :

Accueil - bienvenue sur le site du Service de police de la Ville de Montral
Service de police de la ville de Montréal - Wikipédia

 

[rc1990]

Capte. Merci.

So when were the Metro Cops (that weren't actually cops for the longest time) integrated with SPVM? Or is that just some sort of mutual aid channel?

And what's with the 800-MHz channel at YUL?

Pas de problème mon ami.

I don't personnaly know the answer for these question. However, you can consult the following websites :

Service de police de la ville de Montréal - Wikipédia
Accueil - bienvenue sur le site du Service de police de la Ville de Montral

 

[VORTAC]

Capte. Merci.

So when were the Metro Cops (that weren't actually cops for the longest time) integrated with SPVM? Or is that just some sort of mutual aid channel?

And what's with the 800-MHz channel at YUL?

The change occurred in July 2007.

For 800mhz, Montreal airport is covered by an EDACS system. The SPVM is working on this radio system with a 400 mhz UHF link, which allows them to listen to channel 1. Optionally, they have two private channels on the EDACS system.

 

[TurboLed]

I'm wondering why the Montreal SPVM feed doesn't broadcast channel 7 ? Today a lot of the officers are moving to channel 7 but then we cannot hear them...

I can't wait to get a scanner just to be able to hear all the channels including the simplex ones when they are in my area. I bought a used Pro-76 on eBay (I know, it's analog and not 800 MHz)

 

[plaws]

I'm wondering why the Montreal SPVM feed doesn't broadcast channel 7 ? Today a lot of the officers are moving to channel 7 but then we cannot hear them...

I can't wait to get a scanner just to be able to hear all the channels including the simplex ones when they are in my area. I bought a used Pro-76 on eBay (I know, it's analog and not 800 MHz)

Despite what you read, they are still on UHF, so the 76 will be fine for now.

 

[TurboLed]

Despite what you read, they are still on UHF, so the 76 will be fine for now.

I never said it wouldn't. Just preventing comments like my scanner won't be able to listen to SIM and Laval and this and that.

 

[TurboLed]

Yesterday was an interesting intervention from SPVM. A shooter in a school gym, with a machine gun. 2 suspects were shot dead. I was listening with all my attention, being sure I was hearing live about the scoop of the year...
At the end I learned this has all been a training scenario. Suddenly, all was over and I got fooled.

 

[kirk23]

Yesterday was an interesting intervention from SPVM. A shooter in a school gym, with a machine gun. 2 suspects were shot dead. I was listening with all my attention, being sure I was hearing live about the scoop of the year...
At the end I learned this has all been a training scenario. Suddenly, all was over and I got fooled.

LOL...
Don't feel bad...we have all been fooled by their "excersises" even on duty cops that happen to flip over to that channel think it's real.. unlike other police agencies the SPVM doesn't announce very often during these excersises that it is only a simulation. Normally they use the UQAM on St.Denis as their simulation location.

 

[TurboLed]

Sometimes on my scanner I hear scrambled (digital) transmissions on investigation channels 1-15 (e.g. 408.4125 MHz). Are these encrypted? If not what kind of digital encoding is it?

 

[kirk23]

Sometimes on my scanner I hear scrambled (digital) transmissions on investigation channels 1-15 (e.g. 408.4125 MHz). Are these encrypted? If not what kind of digital encoding is it?

Yes all the Investigation channels are encrypted. . they are not digital..just encrypted.
There is 1 investigation channel that is in the clear..that is 2-11 411.4375 with a ctcss tone of 203.5. it is used mostly during large demonstrations like the student demonstrations earlier this year.

 

[exkalibur]

And what's with the 800-MHz channel at YUL?

YUL is on an 800MHz system. My bet is that the airport has an internal DAS type system (internal antennas to provide coverage in the building). It was probably easier to give the Police 800MHz radios and set up a link between their 800MHz channel and the regular UHF one, than it would be to re-transmit the UHF signal on the DAS.

Also, since the Police work at the Airport, it would make sense for them to carry radios which can inter-op with airport ops in times of emergency.

 

[TurboLed]

There's something weird with the SPVM frequencies these days. Several times during an hour we can hear the morse identification from the repeater, which I'm familiar with. The problem is that on some channels it appears to be off-frequency (noisy) or from a different location. On one of the channels the audio pitch is drifting up while the ID is playing, the tones are getting higher and higher in pitch.
And the funniest part is that on one channel, when officers are talking over the ID the transmissions becomes very noisy but the people talking don't seem to hear it.
Is the ID coming from a different site or is it modulated in another mode than FM ? It's just looking weird sometimes, and the fact that they don't hear it makes me clueless.

 

[plaws]

There's something weird with the SPVM frequencies these days. Several times during an hour we can hear the morse identification from the repeater, which I'm familiar with. The problem is that on some channels it appears to be off-frequency (noisy) or from a different location. On one of the channels the audio pitch is drifting up while the ID is playing, the tones are getting higher and higher in pitch.
And the funniest part is that on one channel, when officers are talking over the ID the transmissions becomes very noisy but the people talking don't seem to hear it.
Is the ID coming from a different site or is it modulated in another mode than FM ? It's just looking weird sometimes, and the fact that they don't hear it makes me clueless.

I've never known the technical details of the system BUT it's apparent (to me!) from listening while visiting that they are using multiple transmitters to cover the island. If you listen carefully (earbuds) you can hear a slight wooshwooshwoosh on the audio signal. As I understand it this comes from the fact that your receiver is closer to one transmitting site than another and the difference in time of arrival, though **very** slight, is enough to detect on the audio. This occurs despite the fact that multiple-transmitter systems have to be extremely closely synchronized.

So, *if* it's true that there are multiple transmitters, then it may be the case that only one of them does the CWID. If you have CTCSS on your radio, many systems are set to NOT transmit the tone during the CWID, so you could eliminate it entirely that way. Of course, if there is someone talking, you'll still hear the ID.

Surely someone here has actual insight (not wild speculation!) into the system architecture that can tell us about it ...

 

[kirk23]

So, *if* it's true that there are multiple transmitters, then it may be the case that only one of them does the CWID. If you have CTCSS on your radio, many systems are set to NOT transmit the tone during the CWID, so you could eliminate it entirely that way. Of course, if there is someone talking, you'll still hear the ID.

Surely someone here has actual insight (not wild speculation!) into the system architecture that can tell us about it ...

Peter has an excellent point regarding using the CTCSS tone... I use the tone 203.5 on all my SPVM freqs and I don't pick up the CARRIER ID at all when using the tone.

That would explain why the police officers will constantly " Talk over " this carrier tone..because they can't hear it when it's transmitted because of the CTCSS tones in their radios

 

[TurboLed]

The CTCSS is used to squelch your radio/scanner when nobody is talking. It doesn't remove audio frequencies while someone is talking and the ID is playing.
So if the ID is playing while an officer is talking, even with CTCSS you will hear it.
On SPVM when officers are talking, usually we still hear the ID but muffled in background.
But recently, on some channels, we clearly hear the ID while they're talking, and sometimes with a lot of background snow noise. And that doesn't seem to disturb them.

On the SQ frequencies, however, the ID will stop immediately if someone starts talking at the same time. It makes me wonder if they still are within regulation if the ID is not playing completely when it should?