New to scanners...

[MetalCowboy]

In an posting on another forum, Aa3rt recently posted:
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As far as your scanner question-most, if not all, signals that scanners pick up are FM and pretty much limited to line of sight. GENERALLY, the range is about 25-40 miles but can be either further or shorter depending on terrain, (hills, valleys, large buildings, bodies of water) how high the transmitting antenna is above the terrain and the power of that transmitter.

The sensitivity of your scanner and most important, your antenna, also make a difference. The best scanner money can buy is worthless without a good antenna.
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Being new to scanners i had a few more questions.
1. were talking about hand-held scanners here right?
2. how do locomotives pick up transmissions from "home" i.e. those who operate signals/switches at the HQ of the track owners. I live on the CSX mainline and I am pretty sure that they are not picking up signals directly from Jacksonville, FL while going through Erie County.
3. who is being responded to when a response is made to a hotbox detector?

thanks,
MC

[tp49]

To answer questions 1 and 2 we are talking about handheld and table top scanners both have approximately the same range. In order to pick up signals from a distance locomotives (and police and fire departments, etc.) use what are called "repeaters" which in essence take a transmission and "repeat" it to where it needs to go. Also it should be noted that transmissions on lower band frequencies can be heard at much greater distances than those on higher bands. For example under the right atmospheric conditions it is possible to hear the California Highway Patrol on a handheld or desktop scanner, however it is hard to hear anything on the 800 mhz band from more than 15-20 miles away.

[roee]

My answer to your question to the best of my knowledge.

1. Yes, but both. A mobile radio will probably get better reception, but that's mostly due to the antenna. If you connect up a good antenna to your handheld, you'll get near close to mobile reception. But also remember, if you have a wide band scanner, it's not going to be as sensitive as a narrow band or a commercial radio set to that frequency.

2. Railroads typically don't uses 'repeaters' as you might think. The home dispatcher doesn't broadcast out at AAR xx from the office to hit 200 miles away. They either send it out by microwave or by a hardwired circuit to broadcast locations near or next to the tracks. Along a typical sub, there will be several of these locations that both the dispatchers broadcast out of, and that it receives the locomotives radio (and does the reverse to send it back to dispatch). Typically the dispatcher can determine what antennas to broadcast off of, but mostly they seem to use them all. That's why you tend to hear dispatch all the time, but can't hear the locomotive.

3. Defect Detectors work in the same manor. They broadcast out to the road channel (if you ever see one, they typically have a small antenna coming off of it) and it is heard by both the train crew and the Dispatch center. Though it is the train crew’s responsibility to report to dispatch any defects that they have received. As for crews answering the detectors (which they don't do where I am) they are basically talking to no one. I believe all radio transmissions are recorded at the dispatch center, and this is the train crew saying we heard you, incase something happened later and they had to pull the tapes.

[tp49]

Actually I believe the microwave or hardwired circuit is right for the railroads, I was thinking strictly from the public saftey radio standpoint and the former just did not come to mind.

[MetalCowboy]

thanks everyone for your help
MC

[videobruce]

Hey MetalCowboy, where was that pic taken??

[MetalCowboy]

Bruce,
I recieved it in an email so I have no clue. Just thought it was a cool picture.

MC