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Eastern Railroad Discussion > PL Tone for RR radios


Date: 11/10/03 10:12
PL Tone for RR radios
Author: nr2d

I just programed some frequencies into my VHF mobile radio in my truck to monitor CSX,South Jersey, NJ Transit and AMTRAK. Does any one know if they use PL or sub-audible tones (AKA tone squelch) on the radios used by the crews or dispatchers? I have a lot of interference in my area and would like squelch the interference.

Rich Dunklee
NR2D



Date: 11/10/03 11:47
Re: PL Tone for RR radios
Author: chessie

No PL tones that I am aware of. We have interference problems ourselves on locomotives radios around CP-VALLEY in the North Jersey SAA and occasionally in Philly as well.


Randy



Date: 11/10/03 12:47
Re: PL Tone for RR radios
Author: jonnycando

CSX does not use PL or low freq tones on the official RR channels. As a result since that band is close to a medical paging system band, overpowered pager transmitters interfere badly with the RR channels. For example comms in Richmond used to be occasionally impossible, until thouroughly threatened MCV put filters on their pager transmitter. Only an occasional burst of pager data on Channel 8 nowadays.



Date: 11/10/03 13:26
Re: PL Tone for RR radios
Author: nr2d

How can you guy's, who crew trains, stand this? It drives me nuts with the interference I get here in my Radio/computer room from the local hospital pager, 1/4 mile away. You all have more intestinal fortitude than I would have. The noise over in west Philadelphia, PA and in the North Jersey/New York must be unbelevable.

Thanks for the info.

Rich Dunklee
NR2D



Date: 11/10/03 13:38
Re: PL Tone for RR radios
Author: radioman2

NS uses 103.5 around linwood,asheville,charlotte,NC. This is used on 160.950 and 160.245 but if you use it on 160.950 you will only hear the dispacher talk, I use it only on 160.245 .This is used to keep the dispacter from hearing all the yard chatter until you tone them up then the specific tower takes away the PL to carrier squelch so he/she can hear the train crews. I wish they had a national pl so you would not hear all the unwanted noise pagers and computers. I know they use a differant pl in tennessee but I did not have time to figure it out.



Radioman2 out



Date: 11/10/03 14:40
Re: PL Tone for RR radios
Author: Pj

As stated as a general rule, no PL's. Smaller operations may have it, but then the loco's wouldn't really be quailified to lead since the channel may have a receive PL enabled (they wouldn't hear anything).

Paging sucks. Usually its been my experience with the Motorola Spectra and Syntor line (RR Spectra included) that the colder the radio, more intermod it will suffer. Once the radio is in a warmer enviroment, it will filter it out properly. A properly cut antenna will also help reject the unwanted signals.

Usually during the winter, if the cab has been kept warm, it should be too much of a problem for the crews.



Date: 11/10/03 15:21
Re: PL Tone for RR radios
Author: jonnycando

The Spectra filters poorly under even miserably hot conditions, but true a properly trimmed antenna can help. Still nothing is immune to intermod when tuned to a frequency that is bombarded with spurious emissions from a poorly filtered transmitter.



Date: 11/11/03 05:49
Re: PL Tone for RR radios
Author: Bryan_


> CSX does not use PL or low freq tones on the
> official RR channels. As a result since that band
> is close to a medical paging system band,
> overpowered pager transmitters interfere badly
> with the RR channels.

In Huntsville, AL I've seen interesting interference on 160.950, the NS (ex-Southern) road channel. NOAA weather radio in Huntsville is 162.400 and there is a local AM station on 1450, with a transmitter near the tracks.

162.400 - 1.450 = 160.950. As a consequence, somtimes crews waiting at Elko Siding in Huntsville sometimes have to put up with that horrible robotic voice cutting in and out.






Date: 11/12/03 06:12
Re: PL Tone for RR radios
Author: Chessie_fan

If two signals are mixing, then there's really nothing that can be done. Where I used to live, there was an amateur repeater on 147.210, and a town public works repeater on 151.025. Every time both were transmitting, the police repeater on 154.845 would be covered by audio from both repeaters. I have the feeling that the amateur repeater was the culprit. Spectras are awesome radios. I have never had any problems with them at all.



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