Staten Island Railway CTCSS Tone Change?

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JustLou

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I noticed lately that my WS1080 was no longer picking up the Staten Island Railway on 470.4375. When I removed the CTCSS Tone (141.3), it started receiving it again. So I put the channel in Tone Search, and it says the Tone is 118.8 now. I just received a new TRX-2 today, and it also tells me the Tone is 118.8 now. What is weird is that I have a Uniden BC125AT still programmed with the old Tone, and it still picks it up. Can someone in the Staten Island area confirm the Tone has changed? Thanks.
 

JustLou

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Thanks. I programmed it into several old radios this morning, and 141.3 works. 141.3 still doesn’t work on the 1080 or TRX-2. It seems they aren’t seeing a Tone. 118.8 pops up occasionally in search mode. I’m not even gonna try and figure this out. I’ll just turn the tone off on those radios.
 

JustLou

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FYI, in search mode, my radio shows 118.8 when they're transmitting their Morse code station ID.
That’s what I’m seeing too. On voice transmissions, I’m not seeIng anything on the Whistler radios. If I enable 141.3, it mutes the audio.
 

Ant9270

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Possible that the TX frequency PL Is 118.8 and the RX is 141.3?
 

k2hz

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A 118.8 or 179.9 PL display is often bogus if there is any AC hum in the station's audio. 120/180 Hz - harmonics of 60Hz - are close enough to the nearby PL toes to fool the decoder. This hum used to be common on some railroad systems that used their own signal wire lines for radio remote control. Not common now with almost all circuits on fiber optics. Those PL tones were often avoided due to this problem.

But, this does not explain why 141.3 is not working in some radios. If they just went narrow band, a radio programmed for wide band may not decode the reduced PL deviation but I don't think that is the case.
 

JustLou

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A 118.8 or 179.9 PL display is often bogus if there is any AC hum in the station's audio. 120/180 Hz - harmonics of 60Hz - are close enough to the nearby PL toes to fool the decoder. This hum used to be common on some railroad systems that used their own signal wire lines for radio remote control. Not common now with almost all circuits on fiber optics. Those PL tones were often avoided due to this problem.

But, this does not explain why 141.3 is not working in some radios. If they just went narrow band, a radio programmed for wide band may not decode the reduced PL deviation but I don't think that is the case.

It's a mystery. As far as I can tell, the Whistlers don't have any issues with any of the dozens of other UHF channels in the NYC area I have programmed.
 

k2hz

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Some scanners may rarely have a firmware issue with a particular PL tone but I don't think that is the case since you say the WS1080 worked before and then quit. I assume you did not do a firmware upgrade when this happened.

I don't know if SIRT has just one or multiple base stations that you are listening to. If it is just one, there is a possibility that something happened that dropped their PL deviation to an abnormally low level and the Whistler scanners are more sensitive to the PL level than other scanners. If scanners are showing the 118.8 PL there is the remote possibility that a 120Hz hum in the base station audio is causing the scanner to assume that is the PL and ignore the actual 141.3 which may be weaker than the hum.

Are there any other systems in the area that are 141.3 PL you can try to monitor to rule out a problem unique to that PL tone in the Whistler scanners?
 

JustLou

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Some scanners may rarely have a firmware issue with a particular PL tone but I don't think that is the case since you say the WS1080 worked before and then quit. I assume you did not do a firmware upgrade when this happened.

I don't know if SIRT has just one or multiple base stations that you are listening to. If it is just one, there is a possibility that something happened that dropped their PL deviation to an abnormally low level and the Whistler scanners are more sensitive to the PL level than other scanners. If scanners are showing the 118.8 PL there is the remote possibility that a 120Hz hum in the base station audio is causing the scanner to assume that is the PL and ignore the actual 141.3 which may be weaker than the hum.

Are there any other systems in the area that are 141.3 PL you can try to monitor to rule out a problem unique to that PL tone in the Whistler scanners?

I do have a couple of other channels programmed in the 1080 and TRX-2 that use 141.3, and they're fine. Queens Fire Dispatch is one of them, and I was listening to it earlier. I really don't know how long the 1080 wasn't picking up the SI Railway. I noticed it awhile ago but just turned the Tone off. I didn't think much of it until I got the new TRX-2 yesterday and it didn't work on it either.
 

k2hz

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The best explanation I can think of is there is some anomaly that has developed on the SIRT signal that the Whistler scanners are sensitive to. If there is hum or other extraneous low frequency tone on the signal in addition to the PL it could cause some PL decoder circuits to ignore the real PL tone.

Many systems drop the PL tone during the CWID so the users don't hear it. If scanners are showing 118.8 during this period I think there is 120 hum on the signal. If I wasn't 300 miles away, I would look at the SIRT signal on my service monitor to see what is going on.
 

JustLou

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The best explanation I can think of is there is some anomaly that has developed on the SIRT signal that the Whistler scanners are sensitive to. If there is hum or other extraneous low frequency tone on the signal in addition to the PL it could cause some PL decoder circuits to ignore the real PL tone.

Many systems drop the PL tone during the CWID so the users don't hear it. If scanners are showing 118.8 during this period I think there is 120 hum on the signal. If I wasn't 300 miles away, I would look at the SIRT signal on my service monitor to see what is going on.

I appreciate your input. Your hypothesis is better than anything I can come up with. :)
 

JustLou

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JFI, I heard them working on and testing the radio system the other day. Now the modulation is louder and the correct 141.3 Tone is working again on the Whistler radios.
 
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