• Beeps and Rings

  • Discussion related to railroad radio frequencies, railroad communication practices, equipment, and more.
Discussion related to railroad radio frequencies, railroad communication practices, equipment, and more.

Moderator: Aa3rt

  by spence.smith
 
I am looking for a CD or other media recording of a railroad telegraph suitable to put in a restored depot as a background sound. Anything that can steer to a possible source would be appreciated. I have done a Google source to no avail.
  by Ken W2KB
 
spence.smith wrote:I am looking for a CD or other media recording of a railroad telegraph suitable to put in a restored depot as a background sound. Anything that can steer to a possible source would be appreciated. I have done a Google source to no avail.
The best search phrase is "american morse code" recordings. Found this one http://www.morsetelegraphclub.org/libra ... rought.mp3
  by EdM
 
Plate F wrote:That was a city police transmission captured on a railroad frequency with the interference tone. So what happened was that the police signal was too strong and pried into the railroad frequency? But why is it only on THAT particular frequency I ever hear the noise or even the wrong broadcast for that fact?
A radio "listens" to frequencies both above and below the local oscillator frequency, the local oscillator runs at either plus or minus the radios IF... That is what an image is, [some people call 'em 'intermods, which means intermodulation products' (or just mixing products)also at various multiples of the local oscillator frequency. These are real signals.. Real radios have preselection to filter these signals out, scanners, being broadbanded, escentially do not. These signals are another reason why an external preamplifier can cause more trouble than it is worth. These signals are real and can cause all kinds of problems, the reason why one is better off with an amateur two meter radio or RR freq only radio over a wide band scanner..... Elsie Kay
  by Plate F
 
EdM wrote:
Plate F wrote:That was a city police transmission captured on a railroad frequency with the interference tone. So what happened was that the police signal was too strong and pried into the railroad frequency? But why is it only on THAT particular frequency I ever hear the noise or even the wrong broadcast for that fact?
A radio "listens" to frequencies both above and below the local oscillator frequency, the local oscillator runs at either plus or minus the radios IF... That is what an image is, [some people call 'em 'intermods, which means intermodulation products' (or just mixing products)also at various multiples of the local oscillator frequency. These are real signals.. Real radios have preselection to filter these signals out, scanners, being broadbanded, escentially do not. These signals are another reason why an external preamplifier can cause more trouble than it is worth. These signals are real and can cause all kinds of problems, the reason why one is better off with an amateur two meter radio or RR freq only radio over a wide band scanner..... Elsie Kay
Nice explanation, thank you.
  by Engineer Spike
 
You guys were right about how the CP system works. The other strange part about the system is that the tones are set up by switching the transmit channels to what they call the “call in channel.” Once the tone is heard, then the dispatcher is spoken to on the main channel. I don’t know why they can’t be set up on the main frequency. They also have special tones to open up waysides to be used as field repeaters.