new to trunking and confused/dissapointed

[Firepanda]

Hello! I used to have an old, analog-only, simple sony scanner a few years ago and I'm looking to get back into scanning again. I've been drooling over the new models (have my eye on a GRE PSR-500) but I need to figure something about trunking first:

As I understand it, you have to program the frequencies of the system you want to monitor beforehand. This seems silly to me. Where is the excitement of finding a frequency if you need to know them before you listen?

But then I read about an improvement: CCO. Oh, now you only need to know one frequency - the control channel.

That's still no fun!

Why can't the scanner... well, *scan* around and then say "oh, this looks like the control channel for a Motorola type 2!, let me switch to trunk mode and try to listen in!"

Or am I missing something?

Thanks

[hfxChris]

Well, you can always find the control channel frequencies manually if you want. But I mean, once you find it...you've found it. You can't keep re-finding it.

Well you could, but it would be an annoying way to monitor...

[n4yek]

Look at it this way, you do know the frequency you need but now you can figure out who is using which talkgroup ID's.

Originally Posted by Firepanda

Why can't the scanner... well, *scan* around and then say "oh, this looks like the control channel for a Motorola type 2!, let me switch to trunk mode and try to listen in!"

My Uniden 396T does that, it is called Control Channel Only Search option, the new 396XT does not do this though.

[rvictor]

Originally Posted by n4yek

Look at it this way, you do know the frequency you need but now you can figure out who is using which talkgroup ID's.


My Uniden 396T does that, it is called Control Channel Only Search option, the new 396XT does not do this though.

My 396XT does it just fine.

Dick

[gmclam]

Originally Posted by Firepanda

Hello! I used to have an old, analog-only, simple sony scanner a few years ago and I'm looking to get back into scanning again. I've been drooling over the new models (have my eye on a GRE PSR-500) but I need to figure something about trunking first:

Let me tell ya, there are a LOT of changes out there. It is a huge jump to go from analog (especially crystal controlled) to digital trunking object oriented programming.

As I understand it, you have to program the frequencies of the system you want to monitor beforehand. This seems silly to me.

Think of it as a large party line (phone system). Lots of people are sharing a few frequencies. Instead of 'extensions' (with phones) you have talkgroups (TGs).

Where is the excitement of finding a frequency if you need to know them before you listen? But then I read about an improvement: CCO. Oh, now you only need to know one frequency - the control channel. ... Why can't the scanner... well, *scan* around

This function in most scanners is called SEARCH. I say this because SCAN means to sequentially monitor frequencies you've already programmed. SEARCH means to check a range of frequencies with a "step" distance between each.

and then say "oh, this looks like the control channel for a Motorola type 2!, let me switch to trunk mode and try to listen in!"

Two points here.
1) When you find a control channel you'll just hear a buzzing sound. The scanners I've seen don't allow you to select more than AM or FM so you have to stop the search and switch the mode. Then scanners like the PSR-500 will show you "information" being received from the control channel - no voices.
2) The voices are actually on different frequencies than the control channel. The "problem" is that when using SEARCH (or a normal scan of the frequencies in FM mode) is that you'll typically only hear a part of a conversation. What the trunked systems do is assign a different frequency every time a new transmission is started. The scanner can only track this when you are "SCANning" the control channel.

But if you're interested in finding new stuff, it is crazier than ever. Now you don't just surf for frequencies; you can surf for different types of systems. Perhaps you'll find an EDACS or LTR type system. If you do find the active control channel of a MOtorola type system, and scan it, then you can surf it for all of the active TG IDs.

And .. since the PSR-500 is a digital scanner .. there is an entire additional topic of surfing/finding/trying to hear digital stuff.

[wlmr]

Originally Posted by Firepanda

Why can't the scanner... well, *scan* around and then say "oh, this looks like the control channel for a Motorola type 2!, let me switch to trunk mode and try to listen in!"

Or am I missing something?

Thanks

Actually you can still have all that fun and more. If you just scan a range of frequencies you'll start noticing some that are just noise (at least at first that's what you'll think!) Once you've become familiar with what control channels sound like, and different systems sound different, you'll get to play with the next step. Program the control channel into the scanner. If you guessed wrong on what type of system, you'll get nothing and have to try and program it as a different type of system. Use up all the available options in the scanner and you'll have to write off the frequency off as something you can't listen to. BUT - if you start decoding the control channel as the right type of system you'll be listening to lots of different conversations separated into talkgroups that you now get the fun of figuring out as well. Figure out enough and you'll know who's control channel you found back at step one.

There, does that sound more like the fun you thought you would be missing out on? Programming the scanner from the superb lists found at this web site is only one way to use a scanner. Read the discussions here and you'll realize that lots of the people here are having fun finding stuff to listen to. Good luck!

[DickH]

Originally Posted by Firepanda

... That's still no fun!
Why can't the scanner... well, *scan* around and then say "oh, this looks like the control channel for a Motorola type 2!, let me switch to trunk mode and try to listen in!"
Or am I missing something?

Yes, you're missing something.
When I returned to the U.S. after living abroad for many years, my thinking was very much
like yours, since I could not monitor anything for all those years while trunking was coming into use. But I sat down and learned about it. It wasn't quick and it wasn't easy, but once I learned it I realized it was more fun than ever. With a trunked system you can hear everyone just as if they were right out in front of your house.
The system where I am uses about 20 freqs., but there are more than 300 active talk groups. Thats like hearing 300 freqs. almost simultaneously on the same scanner. WOW!
Here's how a Motorola trunking system works:

Motorola Trunking:
The object of trunking is to allow many users to share a relatively few frequencies.
A trunking system is controlled by a computer. Information (data) is exchanged between the system radios and the computer on a control channel, sometimes called a data channel. It sounds like a strong buzz.
A large system can have up to 28 freqs., 4 of which may be used as control channels. The control channel may be changed once a day or as often as the programmer decides. Some scanners need only the control channels to track an entire system. Just put in the 4 Control Channels.

Each group of users (Fire, Police, etc.) is assigned TALK GROUPS. In a Motorola Type II system, the most common type, TGs are usually in 32 number steps starting with 16 and going up to 65536; 16, 48, 80 --- 4656, 4688, 4720 --- 28944, 28976, etc. System radios can have more than 100 TGs programmed into them.

After all the freqs. have been entered and it is "trunking", the Banks become SCAN LISTS where you enter the Talk Groups you want to hear.
Use the Talk Group numbers in the DEC column, not in the HEX column.

When a user pushes the talk button on his radio, data is sent to the computer. The computer chooses an unused freq. and sends that data to all the radios using the TG of the originating unit. This all happens in a fraction of a second and it happens EVERY TIME a radio is used.

EXAMPLE:
Fire Dispatch calling Engine 4 (TG 4528 on 856.7125)
Engine 4 answering Dispatch (TG 4528 on 852.2625)
Respond to 73 Elm Street (TG 4528 on 855.9625)
Engine 4 responding (TG 4528 on 851.6375)

If you have entered TG 4528 into your scanner, it will decode the control channel data and change your scanner freqs. to follow the conversation on TG 4528.

This should get you started, but you should read the manual carefully. You may need to read it several times.

EDACS and LTR systems use the same principles, but they can not do Control Channel Only trunking, the TG numbering is different and the frequencies must be entered into specified channels in the scanner.

[lowboy654]

Very well said, Dick
Fun or not that is how trunking works. And I for one think that locking to the talkgroup is way better then my old days in scanning back in the 60's and 70's things have improved.