How to program a trunked system? Looking at WQHX483

[htqueensbury]

Hi! I just started scanning about like two weeks ago, so please bear with me if I seem a lil slow

I discovered this radio tower: https://www.radioreference.com/apps/db/?fccCallsign=WQHX483

So I took all those frequencies and programmed them into a conventional system, only to realize that it was trunked I can hear voices just fine.

Here's what I know:
1) It appears that the step size is 25 KHz.
2) There are three frequencies that jump 150, 250, and 200:
482.5125
482.7625
482.9625

QUESTIONS

1) The type of trunking system this is? How would I be able to determine it myself?

2) I presume that those frequencies listed on the above link to WQHX483 are output frequencies, where you can hear voices, but not control channels. Do I need to find the control channel? If so, how can I find it? I've scanned that frequency range using Custom Search with the following parameters and come up with silence:
482-485, Step 6.25k/12.5k, C-Chan checked/unchecked. Tried Auto/NFM Modulation.

Thanks for any help/resources you can direct me to learn more!

 

[clbsquared]

You need to look under the database for your specific location. You're looking at frequencies for that entire system on the tower site page you linked. What location are you wanting to monitor specifically? Once that is determined, we'll look at the agencies specific info and determine what type of system or is.

 

[htqueensbury]

Well, I'd like to learn how to do things myself rather than relying on the databases. I read that not everything on the databases is correct, so I figured why not delve into discovering things for myself?

In fact, that brings me to the question, how is all that info in the DB derived? For instance, how did someone find the control channels for, say, New York City DoITT (UHF)? I'd like to learn how to find all that out on my own, as if RR didn't exist.

 

[clbsquared]

You need a scanner capable of receiving the type of system you want to monitor. Then you'll need a special software like Unitrunker to decode the control channels. But first, you need to find out what agencies you want to monitor. Then you need to go to the FCC's ULS page and find the license for that agency. The license will tell you which emissions designator the agency is licensed for. This designation will tell you if it's analog, LTR, DMR, P25, etc.

 

[troymail]

Folks use various resources to find new frequencies/systems... the easiest option (in some ways) is to do limit/custom searches. Most scanners will provide some information beyond the frequency the scanner stops on - tone/NAC codes, talkgroup IDs, modulation types (P25, DMR, NXDN, etc.).

It can be a bit easier if you already know most of the systems/frequencies in your area (or the area you are doing your search in). This can help you rule out certain activity as already known so you can move on to other things.

You can also use some avaiable resources to compare the signal you are hearing to known things. An example:
Digital*Modes*Samples
W2SJW - Radio Sounds

If you aren't sure about something you've found, you then would need to do some research - RRDB, FCC license data, etc. Just keep in mind that neither of these are going to be 100%. FCC data is a guide - some things you won't find - others are incorrect for various reasons. RRDB will never be 100% complete (or accurate) either. Some things never get submitted and things change over time.

You can't really program it as a trunk system until you know what type of system it is.

Tools like Unitrunker, Pro96Com and DSD are great once you find a signal or control channel frequency. You program that frequency into your radio and feed the signal to one of these tools. When it decodes properly, they can tell you lots of things about the system - alternate control channels, neighbor sites and their frequencies, callsigns (if programmed properly by the admins), additional system (voice/data) frequencies, etc.

It's like being a detective so you will need lots of patience. However, as with anything else, if it is something you enjoy, you'll learn different approaches and it will become easier over time.

 

[Ubbe]

You probably have to increase your search range to find the control channel, if it's using one.

Start at 470 and use 6,25 step if they are actually using smaller steps.

When you monitor a voice channel you should listen carefully if you can hear any type of background signalling that could indicate that there is sub audio information transmitted that then might not need a dedicated control channel.

/Ubbe

 

[UPMan]

Original questions:


1) To determine the type of trunked system, you'll need to find the control channel and/or all other frequencies being used on it.


2) Rather than use a search range to find the control channel, I'd start by only scanning the frequencies on the license. Note that there are too many frequencies for them all to be on the same system. In the ULS listing, the frequencies are grouped by antenna...I'd start by scanning each set of frequencies per antenna. The link to the ULS listing is at the bottom of the page you linked to in your first post.



3) Later question of how this stuff is determined by RadioReference: It is submitted by users who have search, scanned, and determined the information as you are trying to do.