Help with Understanding frequencies

Status
Not open for further replies.

_DeS_

Member
Feed Provider
Joined
Jun 6, 2006
Messages
140
Location
Cape Breton Regional Municipality
Greetings All,
I opted post here as this my question more so relates to general radio, although I'm going to use my specific area as an example to help with understanding. So hopefully no one gets overly upset and starts the usual why don't you post in the specific area and what not as the area specifics are for example only. If need be feel free to move and my deepest apologies...

So here goes, I'm trying to compile a list of my area fire departments. It has proven to be a little difficult. Each area is divided into Alpha,Bravo etc. etc. So when going through the Canadian Freq Allocation Database and querying a know fire dept, here is what I find.

Query for Gabarus Fire that is in the Gulf Group

Tx Rx
151.3400 155.5050 GABARUS N.S., FIRE CAPE BRETON REGIONAL MUNICIPALITY
153.8300 153.8300 GABARUS N.S., FIRE CAPE BRETON REGIONAL MUNICIPALITY
154.3250 154.3250 GABARUS AREA, GULF GROUP CAPE BRETON REGIONAL MUNICIPALITY
155.5050 151.3400 GABARUS N.S., FIRE CAPE BRETON REGIONAL MUNICIPALITY

Query For Louisbourg Fire that is in the Gulf Group

Tx Rx
151.3400 155.5050 LOUISBOURG N.S., FIRE CAPE BRETON REGIONAL MUNICIPALITY
153.8300 153.8300 LOUISBOURG N.S., FIRE CAPE BRETON REGIONAL MUNICIPALITY
155.5050 151.3400 LOUISBOURG N.S., FIRE CAPE BRETON REGIONAL MUNICIPALITY
154.3250 154.3250 LOUISBOURG AREA, GULF GROUP CAPE BRETON REGIONAL MUNICIPALITY

So I'm new to all this and dont understand how that one fire station can use the same frequency as the other. So let me take a stab at this based upon commonalities on queries of all groups...I'm 99% sure that the 153.8300 is a Mutual aid type freq as ALL groups have it Alpha,Bravo etc, Makes Sense ? Secondly, I would assume that the 154.3250 is the dispatch channel for the group as it is listed the same in both departments as the "Gulf Group" and is the same for all other groups,now what I cant make sense of is the remainder of the freqs, 151.3400 & 155.5050 as they are both listed for both departments as the Rx channel. I assume that in order to hear these in my scanner I would program the Rx channel ? but how can the same 2 freqs be listed as the Rx channel for 2 diff fire depts, and why are there 2 for each department this goes for the rest of the groups aswell....

Any help with making sense of how to program this to hear in my scanner would be greatly appreciated and just any insight to my problem at all is much apprecaite.

Thanks For Any help
 

dangitdoug

Member
Premium Subscriber
Joined
Feb 21, 2006
Messages
329
Edumutated guess

First of all, don't panic. It'a actually very simple. Both sets of listings you show are dispatched from one 911 Comm Center.

This is very common and helps to lower the cost of communications to public authorities. One system is built and put into place with several municipalities paying for the construction and/or usage of the system.

Doug K
 

_DeS_

Member
Feed Provider
Joined
Jun 6, 2006
Messages
140
Location
Cape Breton Regional Municipality
Well thanks for the reply Doug, Im fine with the details of how its dispacthed and designed, I'm sure it makes great sense when someon understands it. So any idea how I would program this in a scanner or any insight into the questions asked towards the end of the post...Thanks.
 
Last edited:

muhockey86

Member
Joined
Apr 3, 2006
Messages
198
Location
Fenton,MO
To program your scanner for that system, all you would need to do is program in all of the Repeater Outputs once...
 

_DeS_

Member
Feed Provider
Joined
Jun 6, 2006
Messages
140
Location
Cape Breton Regional Municipality
muhockey86 said:
To program your scanner for that system, all you would need to do is program in all of the Repeater Outputs once...
Awsome, thats a help for sure...now how would I identify which would be the repeater ?
and just out of curiosity what about the remainder freqs...Oh and jsut for clarification, its the Rx channel that programmed into the scanner correct ?

Thanks for all the help....
 

AG4WI

Member
Joined
Oct 25, 2004
Messages
60
Location
Middle Tennessee
They have the same Freq. But i would guess they use differant Tones. You can have 30 or more dept,s on the same Freq. but each Dep,t would only hear the Dispatch when the correct Tone was sent along with the Freq.

You did not say what Scanner you have but most of the later Unidens have a search feature that searches for the tone that is being Transmitted along with the Freq.
If you don,t understand what Tones are do a search and there is lots of info. that will teach you the basics of useing Tones to transmit to a Certain group of Radio,s.
 

_DeS_

Member
Feed Provider
Joined
Jun 6, 2006
Messages
140
Location
Cape Breton Regional Municipality
Thanks for the reply. I was jsut reading a bit on tones, and that makes total sense to me and yes my scanner does support Tone display, its a RS Pro-97. I'm still at a loss here at which freq to use. as I stated before, using hte example above, the 153.8300 is a mutal aid type freq and they 154.3250 would be the dispatch channel, so im left with the 2 other freqs and not sure which one to use for the specified station..

Thanks again...
 

dangitdoug

Member
Premium Subscriber
Joined
Feb 21, 2006
Messages
329
The only freqs needed for programming are the rx.

If the listings show two separate freqs, (tx & rx) it is a repeated frequency.

If a listing shows only one frequency it is simplex. These signals are radio-to-radio only. No repeater.

Doug K
 

dangitdoug

Member
Premium Subscriber
Joined
Feb 21, 2006
Messages
329
Can you post the link for the database you used? That will help determine if there are separate tones.

Doug K
 

_DeS_

Member
Feed Provider
Joined
Jun 6, 2006
Messages
140
Location
Cape Breton Regional Municipality
dangitdoug said:
Can you post the link for the database you used? That will help determine if there are separate tones.

Doug K
Hey,
here is the link to the databse I used...

http://neon.polkaroo.net/~darkwing/tafl/

This is just a easier way to search Canadas TAFL, it doesnt allow direct linking to results. But if you change location to Nova Scotia and use Gulf as a search criteria you will get my posted results...
 

dangitdoug

Member
Premium Subscriber
Joined
Feb 21, 2006
Messages
329
Okay

I notice both sets of listings end with Sydney NS. Do you know what that is? My guess is that is the name of the Emergency Comm Center for that area, but you need to confirm that.

There are no tones given, which is unusual for a public authority. This appears to be a privately compiled database and someone got lazy with the listings by not posting tones.

I'll check a couple of other databases and see if I can locate tone info for these. Should take about thirty minutes.

Doug K
 

_DeS_

Member
Feed Provider
Joined
Jun 6, 2006
Messages
140
Location
Cape Breton Regional Municipality
Here is the link to the actual canadian database http://sd.ic.gc.ca/engdoc/main.jsp
I'm not overly farmiliar how to use it to be honest, it may list tones ? the other link I posted references this I assume. Your question about Sydney, it is a main city centre in the area and yes that is where the comm centre is.

I really apprecaite all your help here...
 

dangitdoug

Member
Premium Subscriber
Joined
Feb 21, 2006
Messages
329
Start here and work your way in. I looked at it a little and there are several fire listings with no tones. Maybe your area is not that busy abd they don't need tones?

Good luck. I'll check back later tonight and see how you are doing.

Doug K
 

_DeS_

Member
Feed Provider
Joined
Jun 6, 2006
Messages
140
Location
Cape Breton Regional Municipality
dangitdoug said:
Start here and work your way in. I looked at it a little and there are several fire listings with no tones. Maybe your area is not that busy abd they don't need tones?

Good luck. I'll check back later tonight and see how you are doing.

Doug K
Sorry Start Where ?
 

_DeS_

Member
Feed Provider
Joined
Jun 6, 2006
Messages
140
Location
Cape Breton Regional Municipality
OK, maybe this will help someone help me make sense of it lol....

Using the actual Canadian Database : http://sd.ic.gc.ca/pls/eng_alpha/web_search.licensee_name_input

And the searching the following Criteria:
CAPE BRETON REGIONAL MUNICIPALITY REGIONAL FIRE SERVICE

You will get results, ALOT of results, that just make no sense to me...There are alot of options down the bottom of the search page, but im not sure if any of them reflect tones.

Hopefully someone can help me make sense of this, in the context of my initla post.

Thanks again..
 

scanfan03

Member
Joined
Jun 2, 2003
Messages
1,668
Location
Houston, Texas
To look for tones, just put your pro-97 in tone search mode (refer to manual) per each channel, and let it do the work for you. One of the other two frequencies is probably the input side to the dispatch (output frequecy) if they are repeated, while the other would be a simplex channel. If they are not repeated, both of the other frequencies would probably be two different simplex channels (car to car).
 

_DeS_

Member
Feed Provider
Joined
Jun 6, 2006
Messages
140
Location
Cape Breton Regional Municipality
scanfan03 said:
To look for tones, just put your pro-97 in tone search mode (refer to manual) per each channel, and let it do the work for you. One of the other two frequencies is probably the input side to the dispatch (output frequecy) if they are repeated, while the other would be a simplex channel. If they are not repeated, both of the other frequencies would probably be two different simplex channels (car to car).
Hey thanks for the reply, I was aware about letting my scanner do the work for me, the only thing about that is alto of these fire depts are very small and dont see much action, I would be waiting weeks maybe months for any kind of information lol...

I guess what I really need to know is what frequency to use for what department.
 

n7lxi

Member
Premium Subscriber
Joined
Jun 8, 2006
Messages
165
Location
Lancaster PA
_DeS_ said:
Hey thanks for the reply, I was aware about letting my scanner do the work for me, the only thing about that is alto of these fire depts are very small and dont see much action, I would be waiting weeks maybe months for any kind of information lol...

I guess what I really need to know is what frequency to use for what department.
Why not just put them all in and make note of what you hear?
 
Status
Not open for further replies.
Top