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pdfdems286

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i recently spectrumsweeper'ed <gre's trade name for nearby fq.finder> 452.93125 from a pretty high point on the new jersey shoreline overlooking new york city.i got a full bar hit on the s-meter.the conversation was in the older style single phase inversion type of scrambling.i took the antenna off of the radio and was still getting the signal full bar.i searched thru the database and found that it was a frequency assigned to the railroad radio service.i'm not a big rail monitor.does anyone know who may use this fq.in the area's mentioned ?.also i believe that it indicated that it was reserved for low power.
 

burner50

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I dont know why you would hear a conversation there... that is what Fred uses to talk to the headend.

Basically just End of train telemetry... very low power...
 

KC9JUM

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signal that strong is probably an Image.....

FRED (the device on the end of the train) and MARY (the device in the Locomotive cab) use a digital mode to talk to each other.
 

trainman111

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The EOTD frequencies are:
Head-end to rear-end: 452.9375
Rear-end to Head-end: 457.9375

If you listen to them on the scanner and a train is close, all you'll hear is a "squak", but there are programs out there that allow you to decode these squaks so you know what specific information is being transmitted (ie. brake pressure, battery life, if the train is moving or not, etc.). It's quite possible that 452.93125 was an image to the 452.9375. Usually, 452.9375 can be heard over a greater distance than 457.9375 because it's mounted on the roof of the locomotive, making it much higher than the one on the rear of the train which is mounted on the coupler.
 

pdfdems286

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but there would not be any actual voice chatter correct ?. what i am hearing is what i assume are 2 people having a conversation in scrambled "donald duck style" inversion.something like single phase inversion.however i think that form of scrambling was done away with.
 

trainman111

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Correct. There wouldn't be any voice chatter. If the "sound" is lasting longer than 1 second, then it's not an EOT. EOT's are very quick chirps. I'm not sure if it's possible, but if you could record it and post the sound file, that might be the key to solving the problem.
 

burner50

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Correct. There wouldn't be any voice chatter. If the "sound" is lasting longer than 1 second, then it's not an EOT. EOT's are very quick chirps. I'm not sure if it's possible, but if you could record it and post the sound file, that might be the key to solving the problem.
Could also be a DPU, they communicate more often.
 
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