clyde
Member
Radio service testing Ch 1 yesterday. New pl?? Not hering much today.
Vernon PD
- Thread starter clyde
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slammed
Member
What does PL 91.5 mean sorry noob here
kb1hwh-2 said:
slammed said:
PL is a Motorola term that means "Private Line". The number is a Hz value.
Every company seems to have their own name for it...
The generic term is CTCSS -- Continuous Tone Coded Squelch System.
Check the CTCSS Wiki for more information:
http://www.radioreference.com/wiki/index.php/CTCSS
On a related topic......
Did anyone else hear Vernon Animal Control on Channel 1 today a little before 2? Or am I just going crazy...?
-Mark
slammed
Member
Hey I did here animal control today I am not sure what channel because I just put a bunch in I dont really know whats what yet
I was hoping to find I good list on the forum but not yet
I was hoping to find I good list on the forum but not yet
why does it matter if they change the PL if they are keeping the same frequency?
slammed said:
After a review of my audio log, it is very clearly animal control calling H on channel 1 (460.325), and them responding on channel 4 (462.625). Interestingly, there is a MDC1200 data burst when H responds on 4 (which normally only happens on 1, and only from units calling H, not H to a unit) which I decoded to "01 00 9901" which, if my current notes are correct would correspond to a POST ID from portable unit 901 (mobile units are 7XXX, potable are 9NNN with XXX being the car number and NNN being the badge/id #). Very weird. Probably just talking to myself here tho.
Sidenote: The 462.625 has a "roger" tone (when user releases the PTT button) from the repeater, very easy to tell when someone is on that frequency (however the tone itself has no PL. The scanner I use normally does not have any PL capability so I always hear CWID and "roger" tones)
I assume you've got all the ones in the database? I've posted everything I have heard myself. What other frequencies were you looking for?
Tolland DB: http://www.radioreference.com/modules.php?name=RR&ctid=310
-Mark
PJH said:
I thought one of the original reasons it was down was due to the fact they wanted to start using NFM or something? (despite KSI977 not being licensed for NFM yet) Maybe the switch to the new PL was the result of them wanting to make sure "old" radios werent being used alongside the "new" ones. MDC1200 data bursts started when they started using the new PL I believe, so im thinking they have new, or upgraded radios?
Or, maybe the guy that reprogrammed them is lazy. The Motorola code for 91.5 is ZZ
And while I'm on the subject of Vernon PD
....anyone have a list of 'clearance codes'?
...anyone else catch a few days ago when the dispatcher *SAID* "ksi977" at the end of a transmission? That one made me do a double-take.
-Mark
PJH
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All PL tones do is help guard against interfearence. It has nothing to do with radio ID, 25/12.5 channel spacing or anything else.
Since I don't listen the Vernon PD, chances are your hearing the tone remotes, and not a "roger tone". Most radio systems use what are called tone signalling. These are internal tones that tell connected equipment when to key up, change channels etc. Most of the time its filtered out within the radio system but depending on installation, you can still hear them.
The most common time you might hear them on any conventional system is when the base radio is keyed up RIGHT after or before an incoming transmission is finished.
Since I don't listen the Vernon PD, chances are your hearing the tone remotes, and not a "roger tone". Most radio systems use what are called tone signalling. These are internal tones that tell connected equipment when to key up, change channels etc. Most of the time its filtered out within the radio system but depending on installation, you can still hear them.
The most common time you might hear them on any conventional system is when the base radio is keyed up RIGHT after or before an incoming transmission is finished.
slammed
Member
Yes I read and added some of those however what is the difference between the colums frequency and input? or I should say which one do I use? I have a pro 2020
what is the difference between the colums frequency and input? or I should say which one do I use? I have a pro 2020 y10kiscoming said:
clyde
Member
Y10Kiscoming what equipment are you using to decode the MDC1200 codes? Am interested in doing this myself.
clyde said:
I wrote a small Linux application (using the sound card) which utilizes the MDC1200 en/decode library I found on Batlabs (http://batboard.batlabs.com/).
The library is here: http://www.matthew.at/mdc/
Works great for Vernon PD. Also, I noticed certain TN stations have a POST ID. Works there too.
As per the Batlab forums, I'm not sure how legal it would be to distribute my copy of it... and from what I gathered from reading there, writing a Windows version would not be easy... but... it is most certainly on my list of things to do.
-Mark
slammed said:Yes I read and added some of those however
This deals with the way repeater systems work.
Again, the Wiki is a newbie's best friend:
http://www.radioreference.com/wiki/index.php/Repeater
Basically the Input is what the radio transmits on, and the repeater "repeats" it on the output frequency. You will want to be listening to the output frequency, which is the lower one. In the 450-470mhz range, output and input are separated by 5Mhz. So Vernon output is 460.325 and input is 465.325. Listening to the Input is fun only if you want to see if any cars are relatively close to you.
-Mark
slammed
Member
Thank you
Now I gotta learn that wiki thing
Now I gotta learn that wiki thing
y10kiscoming said:This deals with the way repeater systems work.
Again, the Wiki is a newbie's best friend:
http://www.radioreference.com/wiki/index.php/Repeater
Basically the Input is what the radio transmits on, and the repeater "repeats" it on the output frequency. You will want to be listening to the output frequency, which is the lower one. In the 450-470mhz range, output and input are separated by 5Mhz. So Vernon output is 460.325 and input is 465.325. Listening to the Input is fun only if you want to see if any cars are relatively close to you.
-Mark
vs1988 said:
POST ID is an MDC1200 data burst at the *end* of a transmission. It sounds like a "chirp". It basically contains some numbers which include the unit's identification number.
-Mark
clyde
Member
I believe that the Tolland FD are the ones using MDC in the county. East Windsor also is using Ids but they are using Kenwood radios on LTR system. They use the Fleetsync option for Ids.
vs1988 said:
MDC1200 is just one digital format commonly used for ANI (Automatic Numerical Identification i think)
It sounds like this: http://www.kb9ukd.com/digital/mdc1200.wav
Vernon PD is simiar to what you said, but they do it at the beginning of transmissions.
It basically contains an op code, an argument, and a unit ID. Batlabs has a list of the opcodes on the forum, but in general it chooses what the ID is "doing". For example, I have heard Vernon PD accidentally hit their "man down/emergency" button.. all it is is a couple of MDC1200 packets with a special op code. Very interesting stuff..
-Mark
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