Toronto P25 is up

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exkalibur

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The only thing I can assume it might be is that scanners don't properly handle CQPSK which is what the TPS system is using. Simulcast P25 uses a different modulation technique than a non-simulcast. For example, Fleetnet is using C4FM non-simulcast which is why it works fine on scanners, but systems like TPS, Halton, York, Peel and Metrolinx are simulcast which a scanner can't properly handle.

Try turning on your attenuator - it makes my 396 happier on the Toronto system.
 

bigcam406

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im getting 95% control channel signal strength off of north tower,90% off of east tower at my work.at home,its approx 20% off the east tower..i dont think attentuator will solve the problem.im at work now and its sounding fine.must be a location issue im guessing.
 

exkalibur

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The problem isn't signal strength (per say). The issue is that CQPSK doesn't use standard FM. Your scanner's demodulator was designed for pure FM. C4FM is the method that a non-simulcast system uses, such as OPP (Fleetnet) which is why it sounds good. TPS uses CQPSK which uses PSK instead of FM. As a result, your scanner can't properly recover the digital data stream.

By turning on the attenuator, you're reducing the chance of picking up multiple sites which can make reception even worse with CQPSK. On my 396 for example, when I turn the attenuator off, east zone is basically unusable at home, but with the attenuator on, it works "okay".
 

bigcam406

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all due respect,then why is it fine at 1 location,where it works and sounds good with no tweaking,yet at another location,i can barely get a signal? sounds like a location issue to me.BTW, i found out recently that one of the new Durham Region towers is approx a mile and a half from my place.im assuming that might have something to do with it.i tried using the attentuator this afternoon but it didnt make a difference.thanks for your help.
 

Forts

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It has to do with how the CQPSK signal is received from multiple towers simultaneously. Some places will always be better than others as reception from other sites is blocked. Do a search on here for 'CQPSK distortion' or 'simulcast reception' and you will find countless discussions about it. This was one of the big selling features for the new 436/536 Uniden scanners, better simulcast performance.
 
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