Same freqs in CONV and TSYS but different results????

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IronAir

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Hello all,

First post here. I have been reading a bunch and learning a bunch from your fine site, but something still has me baffled. Instead of pulling more of my hair out trying to find the answer, I may as well just ask.

A few weeks ago I bought a new PRO-197 and have been doing my best to get it up and running. I know what you are thinking... "not another newbie asking about how to program his scanner". No, that is not it, I have it mostly figured out.

The question I have is this. When I first got the scanner I was using TUNE and SEARCH to find local freqencies, and found quite a few. These were stored as CONVentional objects. Of course, some of these frequencies were not meant to be listened to alone, but were part of a trunking system. As my knowledge of how this is supposed to work increased, I started programming in TSYS objects. Now I still have the CONVentional objects stored along side the TGRP objects, and they both have the same frequencies, but I hear much more activity on the single CONV frequencies than I do on the trunked frequencies. Why? I hope I have explained this well enough for you to understand what my problem is. There is something in the setup that I have overlooked, or more than likely I just do not understand the system well enough yet to know what is going on.

Here is more detail about what I am experiencing. I live in Traverse City, Michigan. We just had a huge snowstorm last weekend that wiped out a bunch of powerlines. There are line crews from all over the state up here cutting branches and fixing powerlines. I went to the RR freq database and under Consumers Energy, I find these frequencies "064 (40) Traverse City Grand Traverse 01 855.03750 02 855.66250 03 856.88750 04 860.31250a 05 858.86250 08 857.41250c" I program them in under NEW TGRP and NEW TSYS with EDACS standard and all that jazz.

Anyway, I am at a lose, if you can see something that I am doing wrong or why I am not getting all the transmissions on the trunked system that I think I should be, please let me know.

Thanks

Jeff
 

mk262

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I can think of at least one scenario:
The trunked system has say, 100 talkgroups. You have 5 programmed in the scanner and no wildcard talkgroups. You're not hearing the other 95 talkgroups. You listen to the frequencies non-trunked and it sounds like it's going nuts.

Do you have a wildcard talkgroup loaded for that TSYS and/or do you have all the talkgroups you care about enabled (added and not locked out)?

A wildcard talkgroup will enable you to hear any talkgroup on the system. I do see that this system has a great number of talkgroups, listed here.
 
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IronAir

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Traverse City, MI
As far as I can tell there is a wildcard object associated with each TSYS that I have. I am not exactly sure how they come about, but I think they are created automatically when a new TSYS is created. I am using the ARC500 program to help keep things organized (not that it is really helping much). I have tried changing the order of the frequencies, putting the control freq first instead of how it is listed in the RR database, but that didn't seem to change anything. I have wondered if the TGRP's needed to be added individually, but like you said, I should be able to hear all the transmissions using that tower. At least that is how I understand it to work. I have been able to add TGRP's as they pop up during scanning, but not nearly the traffic that I know I should be hearing. Or at least I think I should be hearing.

Something strange is definitely going on though, because I would put the 6 freqs associated with a particular TSYS on one bank and the trunked system by itself on another bank and scan just those 2 banks. When some talk would start up on the CONV freq, I would switch that bank off and try to hear the same talk on the other bank and there would be nothing. Sometimes there would be an "S" for squelch and all the signal bars lit up, but no voice. I am not sure what is going on. I tried setting everything in the GLOBAL menu back to defaults by doing the startup trick by pushing 0, 2, ENTER on the opening screen. Also the control freq is at 99% when I hit analyz.

Probably something simple that I am missing in the PROG part but have not found it yet.

Thanks for the comments.
 

IronAir

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So I have been doing some more reading and research trying to understand exactly how all this Trunking stuff is supposed to work. I found a very nice write up on the EDACS system here...

http://hamradio.arc.nasa.gov/EDACS_Whitepaper.pdf

After reading that, I am beginning to wonder if what I am experiencing is just the nature of the beast while trying to use a scanner to monitor these trunking systems. If I understand correctly, the control frequency needs to be monitored constantly in order to not miss any data that is used for assigning working frequencies to users. Do I have that correct? How can this happen, when a scanner is not always monitoring the control freq?

When I intercept a conversation taking place on one of my CONV channels, and then switch that bank off to see if I can hear it on the TSYS, it is usually not there. I think this may be because the data that was sent out on the control frequency was missed, and it only happens once at the very beginning of the transmission.

Does this sound correct to you guys? Is this what is happening? If so, I am assuming there is no fix for it, that's just the way it works.

Thanks
 

AC9BX

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You have a pretty good grip on this.
As MK262 suggests there's probably an issue of programming with the trunk system.
If you indeed have a wildcard group programmed for a TSYS you will hear everything on that system as you would compared to listening as conventional.
However ...
If you have talk groups for the system programmed in addition to the wild card and you lock out the groups it will skip them. This is a very nice feature of this radio. Let's say you have a system with a handful of groups. You want to hear them all but there's one group of telemetry data. You can listen using wild card, lock out the telemetry group, and hear everything else without having to program in each group.
One issue is having each frequency of the TSYS included and in the correct order. If you are missing one or have them in the wrong order the radio will not track properly. What happens, particularly with EDACS is each subsequent transmission is on a different frequency. The radio monitors the control channel when searching for a desired talk group or for anything if wild card. If it hears what you want the radio switches to the frequency providing the message, leaving the control channel. They unkey. The radio rests during delay again monitoring the control channel for the next transmission for the same group. The next transmission for that group will appear on a different frequency. If the radio can't find it you get nothing.
Some users' systems include non-trunked frequencies. In this case you'll hear traffic on it on conventional but when listening to the trunk it never switches to or stops on on it.
Monitoring trunk systems is noticeably slower than conventional. You're correct, the nature of scanning is you will miss the front of the message. For conventional if the signal is there the radio stops. It's not uncommon to catch something in progress. In trunking the radio needs its instructions for where to tune and such "misses" become more exaggerated.
For small systems with only a couple of frequencies, especially for using wild card, I would just program them as conventional. There's a small LTR system I monitor in which I want all traffic, so programming it as trunked serves no purpose.
 

IronAir

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Traverse City, MI
Thank you WJYSTV62 for the detailed reply. I appreciate you taking the time to write it. I suppose the best way to go about catching the most traffic then is to just sit on the wildcard TGRP in manual mode for a particular TSYS. Seems to be working pretty well so far.

Another question I had, if someone would be so kind...

When you run across an active frequency using tune or search, what is the normal procedure for determining its source, and whether it is part of a trunked system or a stand alone. Some of the frequencies that I have found are not listed in the RR database, as far as I can tell. I have also checked the surrounding counties to try to match them up to something without any luck. One, I have figured out is a propane delivery company, but I do not know which one. Another sounds like maintenance personnel somewhere, but I have no idea where they are. Any suggestions?
 

AC9BX

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One thing you can do when you land on an unknown frequency is to look it up in the FCC database. You can search by a radius around your location. If you find something there that makes sense you can then look at what type of system it is and associated frequencies.
 

kc4jgc

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My guess is that you may not have the system freqs in the correct LCN order. The list you provided listed the LCN as 1,2,3,4,5 & 8. If these freqs are not entered EXACTLY (leaving 6 & 7 blank), your scanner will not track the system correctly. This is true with EDACS & LTR systems. Hope that helps.
 

IronAir

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Thanks guys

I did find a nice website that listed most of the freqs being used in my area...

InterceptRadio.com FCC lookup Grand county (MI state) Traverse

If you guys have found something similar that you like and use please leave a link.

kc4jgc, I actually tried entering them in a few different ways, but did not notice any obvious differences. I tried putting them in exactly as they are listed, skipping 6 and 7, and I tried putting them in with the control freq in 01, but it seemed to work equally well both ways. Strange, because from what I have read, and what you are saying, the order is crucial.

Without having the RR database, with its list of ALL of the freqs and their exact order for a certain trunked system, how would one go about determining this. Is there a way? Is this information also included in the FCC database? Right now, I only see the frequencies that are being used by a specific user, for example, Radio North LLC has dozens of freqs, but how they are used and which ones go together, that is still a mystery.

Thanks for the replies.
 

kc4jgc

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Yes, the order is critical. Those 2 digits before each frequency on your list is the LCN (Logical Channel Number) for that system. those freqs must be entered on you list in that order (855.0375 in slot 1 etc), skipping slots 6 & 7, entering the last system freq in slot 8. I don't know how someone figues out the LCN.
 

kc4jgc

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IronAir, has your issue been resolved?
 
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