InterceptRadio.com Forums

The radio website that puts military & officer safety ahead of profits.
It is currently Fri Mar 29, 2024 1:35 am

All times are UTC - 8 hours


Forums       Map Search       Database Search       Live Audio       Alerts       Wiki




Post new topic Reply to topic  [ 6 posts ] 
Author Message
 Post subject: 161.250
PostPosted: Mon Mar 14, 2011 8:24 pm 
Offline
User avatar

Joined: Fri Feb 20, 2004 8:57 am
Posts: 751
Location: CN87
I've been listening to the BNSF "Line" channel recently (the apparent operation channel north of Seattle and past Everett). Periodically, there will be a tone burst, slight delay, then another tone burst. I then hear the dispatcher talking to someone in the field.

Is this some kind of "wake up" tone that's generated by the train radio? Or, is it something generated by the dispatcher to control or alert someone in the field?

Does any of that make sense? It appears to originate from a transmitter around Everett or Mukilteo, as I hear those landmarks being mentioned.

Does this make sense to anyone?

Brad.

_________________
Whatever.....


Top
 Profile  
 
 Post subject: Re: 161.250
PostPosted: Tue Mar 15, 2011 11:58 am 
Offline

Joined: Fri Apr 30, 2004 8:28 pm
Posts: 1849
The DS normally has a closed squelch for receiving. The DTMF opens up a particular tower and alerts the dispatcher, which opens the squelch. Sometimes they answer right away, sometimes not.

_________________
"I was installing un-programmed radios"


Top
 Profile  
 
 Post subject: Re: 161.250
PostPosted: Tue Mar 15, 2011 7:59 pm 
Offline
User avatar

Joined: Fri Feb 20, 2004 8:57 am
Posts: 751
Location: CN87
Ok, that makes perfect sense. I'll have to listen closer - the tone didn't seem to be DTMF - perhaps one of the two tones is subdued a bit?

Or, my speaker is crappy.....

Either way, thanks.

Brad.

_________________
Whatever.....


Top
 Profile  
 
 Post subject: Re: 161.250
PostPosted: Wed Mar 16, 2011 10:17 am 
Offline

Joined: Fri Jun 01, 2007 7:46 pm
Posts: 777
Location: Portland, OR
I hear that sometimes in Portland/Vancouver; they use the tone to wake up the dispatcher.

_________________
Mt Wave SAR member
Support Search & Rescue: Get Lost!
http://www.mwave.org


Top
 Profile  
 
 Post subject: Re: 161.250
PostPosted: Sat Mar 19, 2011 1:12 am 
Offline

Joined: Sun Mar 19, 2006 8:41 am
Posts: 117
Location: Salem, OR
As you are hearing there are two tones, the first one (this could also be a DTMF string) the second one will be the base station's transponder to acknowledge the call. If the train crew does not here the transponder then they know they need to tone the dispatcher again.

Jim


Top
 Profile  
 
 Post subject: Re: 161.250
PostPosted: Sat Mar 19, 2011 12:25 pm 
Offline
User avatar

Joined: Fri Feb 20, 2004 8:57 am
Posts: 751
Location: CN87
n7maq wrote:
As you are hearing there are two tones, the first one (this could also be a DTMF string) the second one will be the base station's transponder to acknowledge the call. If the train crew does not here the transponder then they know they need to tone the dispatcher again.

Jim


Yea, I've been listening a little closer over the past few days. I occasionally hear the mobile DTMF strings, followed by the base station with the "acknowledgement" tone. Most of the time, I guess I don't hear the DTMF input, because the trains are likely out of range - but the base station is not.

Thanks for the clarification, all.

Brad.

_________________
Whatever.....


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 

All times are UTC - 8 hours


Who is online

Users browsing this forum: No registered users and 11 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by electricity. Copyright © 2013 Interceptradio.com