Are QCII tones a finite set?

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fogster
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What radios do you own?: XTS2500/5000, XPR7550/5550

Are QCII tones a finite set?

Post by fogster »

Speaking as someone that's never programmed a Minitor...

I've noticed some scanner-oriented sites listing "Fire Toneouts," but they rarely map up with the exact tones I see in the QCII tone tables. For example, one site lists my local fire department as using 898.2, 734.7 for tones. Neither tone is in the tables on Batlabs (or any other site, for that matter). Receiving them over the air, a decoder app I have shows 903.2, 726.8 -- tones that are in the table.

What I'm wondering is who's right. Assuming they're not using bizarro equipment, do Motorola console / Minitors / Quick-Call II enabled radios support entering arbitrary tone frequencies, or do they require you stick with the tables? I have a hunch that people are using scanners / software to ID the tones, and they're posting the exact tones their soundcard sees, but they're a few Hz off. But maybe I'm the one that's wrong, and you've been able to use 898.2 for ages.
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SteveC0625
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Re: Are QCII tones a finite set?

Post by SteveC0625 »

fogster wrote:Speaking as someone that's never programmed a Minitor...

I've noticed some scanner-oriented sites listing "Fire Toneouts," but they rarely map up with the exact tones I see in the QCII tone tables. For example, one site lists my local fire department as using 898.2, 734.7 for tones. Neither tone is in the tables on Batlabs (or any other site, for that matter). Receiving them over the air, a decoder app I have shows 903.2, 726.8 -- tones that are in the table.

What I'm wondering is who's right. Assuming they're not using bizarro equipment, do Motorola console / Minitors / Quick-Call II enabled radios support entering arbitrary tone frequencies, or do they require you stick with the tables? I have a hunch that people are using scanners / software to ID the tones, and they're posting the exact tones their soundcard sees, but they're a few Hz off. But maybe I'm the one that's wrong, and you've been able to use 898.2 for ages.
There are other tone systems besides Motorola's QC-II. Reach, Plectron, GE, QC-I, Bramco, and more. This page should help. I keep a summary from this on my laptop, my smartphone, and in a hard copy binder on my desk.

http://genave.com/two-tone_paging.htm

You will find intermixed tone usage on many dispatch systems. One department has used Plectron for ever and a day while another is stuck on QC-I. Yet another uses QC-II. Very few areas have actually settled on a single code plan for their entire coverage. There's almost always a maverick in there. I've even heard of mixing tone types within a single pair.

The tones you are monitoring are correctly tones 5 and 9 from QC-II Reed Group 5. I don't see the 898.2/734.7 on any of my charts. I suspect that who ever reported that tone set for that list was using a decoder that is inaccurate or the tones may have been slightly off freq when measured and reported. Older encoders could drift a bit. Newer ones are steadier. Your hunch is almost certainly what has happened.

Decoding radios like the Minitors are supposed to handle a slight variation in tone frequency; probably up to 1% or so. My own experience varies from that, a lot. My squad uses Plectron 1130/992 for alerting to Minitor V's. I've measured the actual on the air tones from dispatch using a cell phone app and they are 1122.5/928.1 which are Group 6/Tone 0 and Group 2/Tone 9 from the QC-II chart. Yet when I reprogram a Minitor V to the Motorola tones, it won't alert when the tones are sent out. Set it back to the Plectron tones and it alerts fine. The cell phone app (Radio ID) that I am using does properly and accurately decode other agencies' tones on the same radio frequency and all of them are local to me. They're all coming out of the same tone generator. I've tried using the User, Motorola, and Plectron settings with identical results. The Minitors are set up using User tone system and have a mix of the Plectron tone pair for primary alert and a tone pair from the old QC-I chart for backup alerting. It's a real head-scratcher for me.
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fogster
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What radios do you own?: XTS2500/5000, XPR7550/5550

Re: Are QCII tones a finite set?

Post by fogster »

Thanks, Steve! Very helpful info!

Funny that you mention Radio ID; that's exactly what I've got on my phone. I installed it to try to decode some GE-Star traffic, but found it very helpful with tones as well. Wanted to confirm that it was more accurate than what I was seeing people post online, which seems to be the case.
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