OPP and NOR in the past

[w3rwn]

It was for sure state of the art and ahead of its time in terms of integration but it never made much sense to me from an officer safety perspective. The fact that they went back to a traditional "one to many" system with FleetNet is evidence that they weren't happy with the "one to one" design of NOR.

I imagine it would have been far cheaper to go the way of the Alberta PACS system, or the Quebec RITP system where they're regular conventional channels and the Officer pushes a Request to Talk button, which brings up the dispatcher. That could have been done with off the shelf equipment available at the time.

PACS was a generation later than the OPP System. The OPP system was purchased and stored in a warehouse for years, waiting to be deployed, so it appeared to be deployed at or slightly later than PACS. Much of the OPP systems equipment was out of date when it was deployed. The Audio Switching in the OPP controller/console system was done using a custom designed Ward Beck switch. Ward Beck or WBS was a Toronto based maker of studio audio consoles. The Audio multiplexers were all analog frequency division multiplex, when the entire telecom world had migrated to digital TDM etc. Ontario deployed a museum piece as a new radio system, and it was still better than the old low band system.

 

[exkalibur]

I didn't realize Motorola made stuff for the railways back in the day, that's a market they've most certainly lost. Fun fact, the system that Ontario Hydro has for their low band system is using a SafeTran system intended for the Rail market as the requirements (extremely remote base sites) are pretty much identical. Most of them are regular analog dial-in sites.

 

[w3rwn]

I didn't realize Motorola made stuff for the railways back in the day, that's a market they've most certainly lost. Fun fact, the system that Ontario Hydro has for their low band system is using a SafeTran system intended for the Rail market as the requirements (extremely remote base sites) are pretty much identical. Most of them are regular analog dial-in sites.

I remember Hydro used Redicode DTMF mics which were rectangular, with a plastic film DTMF keys and a steel PTT switch.

 

[RFI-EMI-GUY]

I don't recall the exact date it switched over, but I have some system documentation that has a copyright date of 1985 so I'd imagine around that time. The radios were originally a Syntor (later a Spectra) so whenever that was a current model would be a good guide.



So each site generally had two frequencies (originally, there were 3 channels assigned to each site, A, B and C but in practice, only a few got 3 frequencies). One would always be transmitting the marker signal, the other idle frequency would be used for the next voice comm. The best way to scan them was with a PL capable scanner, as voice comms transmitted with a tone of 107.2 (although sometimes the marker also got sent with this, so it was annoying). If you didn't have a PL capable scanner, you'd lock out the current marker channel and once you heard it pop up on the other channel, you'd know there is voice comms on the "old" marker frequency.

A normal system call (in NOR mode) would essentially be what is now called a private call between the PCC and the Officer. The tower's output would have the comm center and you'd only hear the Officer very quiet likely due to cross-talk in their handset. This represented the vast majority of calls on the system. Though, you could listen to the input frequency if you were close enough.

They could also set up a "line patch" which allowed two units to speak directly. This tied up both tower frequencies (one unit on Channel A, the other on Channel B).

They could also set up a "TAC", or Tower All Call. Basically it turned one of the channels into a conventional repeater. The dispatcher would set up a TAC, then the units involved would push the TAC button on their radio. This would remain until the PCC knocked down the TAC.

I managed to find a picture of the control head, attached to this message.

On this model, there's a "TEL" button which was a telephone interconnect feature, but was later replaced with an "AUX" button which allowed an additional frequency to be programmed (such as a Fire Department, or something else location specific).

"COM" was Provincial Common, 142.770
"RTT" was Request To Talk, the Officer would push this and the PCC would respond.
"PRT" was the Pac/RT button to enable the mobile repeater.
"SIM" was to allow them to select a Simplex frequency. They could select SIM 1, up to SIM 19. SIM 2 was the "A" frequency of whatever tower they were sitting on.

The long yellow "banana" button was an emergency button. The green buttons were status buttons - AVaiLable, ENRoute, At Scene, DETachment, OFf Duty, DISpatch, LOG on/off and GRouP select (to manually select a different dispatch zone).

During normal use, the screen would look something like "NOR 2 AVL M" meaning Normal Mode, Tower Group 2, Available, and repeater in Mobile mode.

Useless trivia, but the system wasn't actually called "NOR", rather NOR was the "Normal" operating mode - so you'd often hear them referring to the system as NOR. In documentation, it was just referred to as the "OPP Radio System"

That looks like a prototype Syntor x9000 control head. What was the control channel data scheme?

 

[exkalibur]

I found this YouTube clip, you can hear what it sounded like when a NOR call was released - at about the 10 second mark.

 

[RFI-EMI-GUY]

I found this YouTube clip, you can hear what it sounded like when a NOR call was released - at about the 10 second mark.

Sounds much like MDC1200 signalling which was a Motorola thing at the time. Motorola MetroCom transit systems also used it if I recall.

 

[w3rwn]

I found this YouTube clip, you can hear what it sounded like when a NOR call was released - at about the 10 second mark.

Hearing that brought back memories of my Realistic scanner before scanner had CTCSS.
Refresh my memory.. When a base station at a site was busy, did the marker tone then come up on the alternate channel at the site?
Or did the marker on the alternate channel start when that MDC release sequence was sent?

The original OPP Analog system used MSR 2000 crystal 100 Watt base stations.
They had a rack mount base station controller that generated the MDC 1200? signalling


The other big change over time was the use of handsets, transitioning to hand mics now.
In the initial OPP Analog system, the mobiles had handsets with the thought that an officer might want to hear the dispatcher without others in the patrol car hearing the dispatcher audio.

 

[exkalibur]

Hearing that brought back memories of my Realistic scanner before scanner had CTCSS.

107.2!

 

[mrweather]

Yep, that "sqwak.. sqwak..... sqwak-sqwak" brings back memories.

 

[smackdaddy]

Refresh my memory.. When a base station at a site was busy, did the marker tone then come up on the alternate channel at the site?
Or did the marker on the alternate channel start when that MDC release sequence was sent?

You are correct. I remember the days before I had a receiver with CTCSS decode. I would sit on the idle channel because it would not be keyed at all. As soon as it keyed up with the MDC marker it was time to flip to the other channel and listen to a conversation. Then after the conversation dropped that channel would become the idle channel and be silent until another call began.

 

[mrweather]

Just after getting my Basic licence in 1999, I picked up a used Yaesu FT-5100 and specifically bought the CTCSS decoder board so I could monitor the OPP.

 

[Gymbag]

You are correct. I remember the days before I had a receiver with CTCSS decode. I would sit on the idle channel because it would not be keyed at all. As soon as it keyed up with the MDC marker it was time to flip to the other channel and listen to a conversation. Then after the conversation dropped that channel would become the idle channel and be silent until another call began.

I too used to do the same thing lol until I got my RELM 200 portable scanner.

 

[mikewazowski]

If you had a Motorola radio with Data Operated Squelch, it would detect the MDC600 data on the channel and mute it.

I remember listening to the system on my FRG9600 when the system went live in Southwestern Ontario. The FRG9600 passed CTCSS tones so as soon as I heard voice, I heard the tone. Called a friend who worked at Motorola and he confirmed the system was using 107.2 Hz.

Next day, I had a BC590XLT and the optional CTCSS board on order.

 

[SmileyFM]

Here are some details on how the old MSR2000 were setup for NOR:

VA3OPP: Equipment

 

[SuitSat]

I'm so glad I clicked this thread - love reading about early "oddball" systems. Thanks for all the info, guys!

Ditto ! Love those oddball too !

If you remember, we started discussing about "NOR" here : Early pseudo-trunked system.
As this other thread is locked, I'm very glad to see this informative topic revived with a lot of valuable knowledge, Thx all !

NOR meant NORmal mode. The system could also work in SIMplex mode, COMmon mode or a TAC (Tower All Call).

Thanks a lot for the Spectra SP NOR control head picture ! Been searching for that a LONG time !
The control head was VCN1020A, IIRC...

As for the radios, was it V1377A ? or maybe V1296 ? (can't remember which Spectra revisions it was...).
IIRC they were originally used with Ackermann handsets ?

If memory does not fail me again, that head was originally planned for Syntor before seeing use on the SP Spectra, right ?
I can't remember if they used that particular custom head with Syntor at all (I think it was the case, but I'm no longer sure about a ton of stuff...), or if they went directly to the Spectra (as, as you said, the materiel was left "dormant" for some time...)

TAC stood for Tactical.

But, IIRC, in my clouded memory, TAC was "Total Access Channel" ?!
Not "Tower All Call" (but it could be, seems logical enough), not "Total Area Coverage" (that's for the Spectra-TAC comparator), and not TACtical either... (But I could (probably am) be wrong)...

Can someone shed some light on this please ?

the OPP found that the leased lines between sites were not reliable enough and put the system on hold until they could build out a microwave network.

True that ! In the 2 GHz band IIRC ?

It was also the console system for the Toronto Police, in the first iteration of radio upgrade after the old GE VHF system that used a marker tone when idle.

Don't remember that one, can you please enlighten me a bit ?
Something akin to GE-Marc V (or maybe like the WR "Trac" DTMF system) ? Or was it a simple "channel marker", like the old IMTS 2000Hz Idle Tone ?


And for ALL, thanks a lot for all these new and valuable informations !

 

[exkalibur]

The control head was VCN1020A, IIRC...

Correct!

As for the radios, was it V1377A ? or maybe V1296 ?

They had both. It was a standard Spectra, but it had a custom MLM. You could swap in a regular MLM and a regular Spectra control head and revert it back to a normal radio.

IIRC they were originally used with Ackermann handsets ?

They had two versions, one with the Ackermann handset and one with a standard hand mic. The hand mic was used on motorcycle radios (which also had a custom plastic enclosure for the control head, made it nice to get mint condition ones after they were removed from service).

They continued to use the Ackermann handset on the Astro Spectras with Fleetnet, but ditched that and use regular palm mics on the new system.

If memory does not fail me again, that head was originally planned for Syntor before seeing use on the SP Spectra, right ?
I can't remember if they used that particular custom head with Syntor at all (I think it was the case, but I'm no longer sure about a ton of stuff...), or if they went directly to the Spectra (as, as you said, the materiel was left "dormant" for some time...)

The original radios were Syntors. I don't know how many of them were actually implemented as they were already outdated by the time the system went live. I've seen at least one Syntor VHF NOR radio so they did exist.

The original setup used a VHF radio and a UHF PAC-RT with a custom interface box in the middle of the two. It was quite the contraption.

But, IIRC, in my clouded memory, TAC was "Total Access Channel" ?!

Yes, my mistake about Total Area Coverage - that is what a SpectaTAC stood for. I checked a manual I have and you're right, Total Access Channel.

 

[w3rwn]

Ditto ! Love those oddball too !

If you remember, we started discussing about "NOR" here : Early pseudo-trunked system.
As this other thread is locked, I'm very glad to see this informative topic revived with a lot of valuable knowledge, Thx all !


Thanks a lot for the Spectra SP NOR control head picture ! Been searching for that a LONG time !
The control head was VCN1020A, IIRC...

As for the radios, was it V1377A ? or maybe V1296 ? (can't remember which Spectra revisions it was...).
IIRC they were originally used with Ackermann handsets ?

If memory does not fail me again, that head was originally planned for Syntor before seeing use on the SP Spectra, right ?
I can't remember if they used that particular custom head with Syntor at all (I think it was the case, but I'm no longer sure about a ton of stuff...), or if they went directly to the Spectra (as, as you said, the materiel was left "dormant" for some time...)


But, IIRC, in my clouded memory, TAC was "Total Access Channel" ?!
Not "Tower All Call" (but it could be, seems logical enough), not "Total Area Coverage" (that's for the Spectra-TAC comparator), and not TACtical either... (But I could (probably am) be wrong)...

Can someone shed some light on this please ?


True that ! In the 2 GHz band IIRC ?


Don't remember that one, can you please enlighten me a bit ?
Something akin to GE-Marc V (or maybe like the WR "Trac" DTMF system) ? Or was it a simple "channel marker", like the old IMTS 2000Hz Idle Tone ?


And for ALL, thanks a lot for all these new and valuable informations !

Motorola used TAC, for example in SpectraTAC voting receivers, as Total Area Coverage.
That referred to wide area receiver voting, which is very different from the TAC button on the OPP control head.

The photo below is a Motorola SpectraTAC Receiver, and SpectraTAC comparator.
Comparators like this were used in the Comm Centers to vote the various SIM channel receivers, and to display to the Dispatcher what site/tower a SIM channel user called in on. The SIM base stations sent a tone down the wireline control to the comparator. The absence of tone indicated a mobile was transmitting, then the comparator voted the least noisy signal and sent that to the console/dispatcher.
The SIM Transmitter selection was done on the Console with buttons, and a specific tone-remote-control tone for each SIM transmitter was used for signalling. Typically the dispatcher used the site/transmitter that the mobile called in on.

 

[Service9]

Motorola used TAC, for example in SpectraTAC voting receivers, as Total Area Coverage.
That referred to wide area receiver voting, which is very different from the TAC button on the OPP control head.

The photo below is a Motorola SpectraTAC Receiver, and SpectraTAC comparator.
Comparators like this were used in the Comm Centers to vote the various SIM channel receivers, and to display to the Dispatcher what site/tower a SIM channel user called in on. The SIM base stations sent a tone down the wireline control to the comparator. The absence of tone indicated a mobile was transmitting, then the comparator voted the least noisy signal and sent that to the console/dispatcher.
The SIM Transmitter selection was done on the Console with buttons, and a specific tone-remote-control tone for each SIM transmitter was used for signalling. Typically the dispatcher used the site/transmitter that the mobile called in on.


View attachment 170156

Spectra Tac was also used on the Provincial Common channel. The Spectra Tac Receiver modules were part of the MSR 2000 control shelf. The dispatcher could enable the repeat function on the PC channel by a simple switch on the console.

The mobile repeater was a full duplex Mitrek mobile that had a onboard duplexer and a modified DPL board to decode RTT and ERTT coming from the portable radio. The original mobile set up for a standard car was a Syntor , Logic Box and Mitrek. I would set them up as a complete package ensuring all audio levels were set correct and the digital squelch for the MDC was set to 18 dB Sinad.

It was truely an one of a kind system that worked. And you were able to repair all equipment at a component level.

Ministey of Health tried to have a similar system designed by GE. That didn't work out so well!!!

 

[Forts]

107.2!

I still vividly remember the one dispatcher at Chatham Comm Centre..

"Chatham Comm Centre clear, 16:35... brawwwk brwk brwk"

 

[exkalibur]

I still vividly remember the one dispatcher at Chatham Comm Centre..

"Chatham Comm Centre clear, 16:35... brawwwk brwk brwk"

A ham I used to talk to from time to time worked at the old Burlington Comm Centre, he said that the "squawk squawk" often came over their headset at the end of a call, followed by an open squelch. Said it was quite annoying!

You can tell the old school dispatchers (not that there's any left now); They'd say "go ahead" after every transmission and "call release" at the end. It held over on FleetNet days for quite awhile.