neilbell
Member
When programming a P25 Phase I Moto type system can I just enter the control channels or do I enter all the freqs listed in the RR database for that system? System is SF bay area and called EBRCS.
TRX-1: control channels only ??
- Thread starter neilbell
- Start date
- Status
Redneck0410
Member
For most I believe you will be fine. With the scanners I own I do that and have no issues tracking any system.
Sent from my SM-G930F using Tapatalk
Sent from my SM-G930F using Tapatalk
troymail
Silent Key
Depends on the system -- in most cases, programming only the control channel(s) for the site(s) you want to monitor will work just fine. However, some systems indicate that ANY of the site's frequencies could potentially be a control channel.
With the exception of systems that are hard to receive (i.e. digital simulcast), there is no harm in programming all of the frequencies for any given site.
To be clear - you may not want to program all sites of a multi-site system unless you expect to be near and/or traveling through those areas - just include the sites closest to your location.
Trx 1 control channel
The trx 1 works great without using control channel you can limit search just nxdn only for example and it will skip everything else and not lock onto a cc channel also giving you all the nxdn frequencies in that range. If you limit search uniden it searches everything locking on to all kinds of stuff.
The trx 1 works great without using control channel you can limit search just nxdn only for example and it will skip everything else and not lock onto a cc channel also giving you all the nxdn frequencies in that range. If you limit search uniden it searches everything locking on to all kinds of stuff.
donirving
Member
This is precisely the problem I am having with my SDS100. Is there a way to make it not do that? Two sites take up about 6 seconds making me miss far too much on my conventional channels. I read somewhere about scanning traffic channels only, but I can't imagine how that would possibly work. with the conversations jumping all over the place.
Info would be appreciated! and thanks!
Don
hardsuit
Member
donirving - I use a ICOM R30, even though its NOT a Trunking scanner, it Scans faster than a Scanner WITH Trunktracking. I program just the one system per bank and rescan it over and over, I can even use Voice Scan feature or scan in Reverse Order. people complain that the ICOM R30 is not Trunktracking but I've known for Decades that a CR outperforms Scanner 10x. the Whistler TRX-1 is a good option if you want more Digital Modes.
hardsuit
Member
neilbell - if you got a TRX-1 why are you programing manually ?
its less Headache and Faster to simply update the scanner through the EZScan software and the Radio Reference Database. I update every week, takes just a few minutes.
besides I think the TRX-1 can Trunktrack P25 I just fine. which is why you want to program using the PC software.
its less Headache and Faster to simply update the scanner through the EZScan software and the Radio Reference Database. I update every week, takes just a few minutes.
besides I think the TRX-1 can Trunktrack P25 I just fine. which is why you want to program using the PC software.
donirving
Member
Great, a cool old school approach using the venerable R30 - I love it. Is there public safety only on your systems or do you have to listen to public works, animal control, etc?
And I would love to hear from anyone (ynot58, others?) how the TRX-1 accomplishes scanning without control channels. Does it just stop when it hears the desired talk groups then quickly scan again to pick up each reply? I almost bought one and still might get the TRX-100 when it comes out. Not that I really need LSM right now - I don't think our Silicon Valley "SVRCS" system is using simulcast yet, but their dozen or so new FCC site licenses for building tops and hill tops paint a picture of the future.
Don
DJ11DLN
Member
The scanner checks the control channels you have entered for activity corresponding to the talkgroups you have programmed. When it picks this up (decodes it), it switches to the frequency the activity is taking place on and unmutes. Data on the voice channel indicates if it should stay on that frequency and wait for more activity during delay or switch to another frequency; once the convo has ended it resumes scanning, i.e. checking the control channels you have entered as well as zipping through whatever conventional frequencies you have programmed. If you have more than one site/control channel plus alternate programmed, this will slow things down. Likewise it has to periodically scan the conventional channels you have programmed and it can't do that and watch the CC at the same time. So no, techinically it doesn't scan without the CCs...I suppose you could just program all the frequencies used by the TSYS sites in range and scan those conventionally, but it would be hit and miss trying to follow a conversation as the sites often roll frequencies between transmissions. You would need to have delay set to 0 to have any chance of following a comm.
Ideally just having one site/CC + alternate entered and no conventional channels, you should hear everything you have programmed for that site. But that's not a realistic way to employ an expensive radio, IMHO.
My experience with a 436 and several predecessors of the TRX series (PSR800/900 pattern) is that the Uniden seems to dwell on sites even when there is no signal present (i.e. far out of range), where the GRE/RS/Whistlers seem to treat the CCs like conventional objects, i.e. they don't dwell if there's no signal present. That makes them seem to scan faster than the Uniden. This entire last paragraph is speculation on my part, based on using the radios in question and if I'm incorrect I'll be happy to hear what is really happening with these things.
JoeyC
Senior Member
In order to monitor specific talkgroups on a system you must program control channels. By not programming (or scanning as some other user was suggesting) the control channels, you are subject to listening to everything and anything on the system, police, fire, dog catcher, street sweeper, maintenance workers and you would have to chase frequencies if you want to follow a conversation.
If the few seconds held onto a trunked system during scans with conventional frequencies also is too much that you never get to hear the conventional, then you should be using separate scanners for each, otherwise you can listen to all of it and put up with the limitations stated above.
hardsuit
Member
donirving - I live in the SF bay area , so I have the Nine Counties region programed into all my scanners.
my Whistler scanner(s) are quite selective in what an Listen to, its all a matter of Programming.
however with the ICOM has smaller memory 2000 CH max and there is no Database Programming, I have to enter Frequencies manually but software should be available later. so the ICOM can listen to all the same stuff as Whistler but everything is manual. but I have been Programming this way for Decades, I used to have a Pen and Paper frequency list that I compiled from " Police call " books. but Radio Reference database makes programming easier.
my Whistler scanner(s) are quite selective in what an Listen to, its all a matter of Programming.
however with the ICOM has smaller memory 2000 CH max and there is no Database Programming, I have to enter Frequencies manually but software should be available later. so the ICOM can listen to all the same stuff as Whistler but everything is manual. but I have been Programming this way for Decades, I used to have a Pen and Paper frequency list that I compiled from " Police call " books. but Radio Reference database makes programming easier.
donirving
Member
Ok, you're saying that there is is indicator data on the voice channel whether to stay or switch ? I figured that the system would drop the voice channel instantly to free it, then if there is a reply the replying unit would have to make a new request to from scratch CC for a channel. I would be interested in reading more about things like this if you or anyone is willing.
And I can report that the SDS100 does not dwell significantly on our more remote (for me) "South" site if it can't reach it. If I am holding the scanner in front of me the site indicator may not annunciate "South" or flashes briefly - not much longer than a conventional scan-over flash. But if I hold the scanner up over my head to get more signal it is more likely to dwell.
donirving
Member
I have all of the nine except Napa in my PSR600 scanners programmed in different VS as car trips from San Jose. And LOL on paper, pencil, and Police Call. Weird to think back.
donirving
Member
Ok, so there are no scanner-detectable talk group indicators available in the traffic channels, and you have to listen to everything. It sounded like Whistler had some special way of selecting talk groups from traffic channels - guess not.
I have more handheld scanners (PSR500s), so I may wind up using multiple again. I can also increase delay on the conv channels so that at least once it stops there there will be more chance of still being there for the reply instead of missing it.
Thanks again,
Don
DJ11DLN
Member
The voice channel has to carry some data so that the subscriber radios know whether to stay on the same frequency or roll to another one; I'm presuming that trunking scanners use this data also. Neither subscriber equipment nor scanners can watch the CC while passing VC audio.
Otherwise, when the system rolls when we're paused or holding, we'd lose the comm. But we don't lose it, whatever comes across that TG during pause/hold continues to be passed by the scanner regardless of which frequency the site decided to use.
I don't have the SDS100, my CC dwell comments are based on my 436, so I'm not surprised that it behaves differently. I would view what you describe as a definite improvement.
ngel
Member
I have a Whistler TRX-1 and on Motorola , EDACs, P25, and LTR systems you can "follow a talkgroup". The terminology is "hold or pause" on that talkgroup and the scanner will follow no matter what frequency that talkgroup moves to, that's if you have the system properly programmed as a trunked system.
You cannot follow DMR , or NXDN in the same way as they do not decode the control channel on those types of systems, that being said I have local DMR and NXDN systems as conventional and have no problem following talkgroups, however they are not busy systems.
Last edited:
donirving
Member
Can you confirm something for me about the TRX-1?
For P25, I presume that in order for the scanner to be properly programmed for trunking it needs to scan the control channel in order for it to jump immediately and correctly to each next assigned voice channel? Without the control channel wouldn't the scanner just resume its scan of the voice channels and stop blindly on the next one it hears - same talkgroup or not? That's what people seem to be telling me.
I guess the answer hinges on the question of whether there is data available in the voice channels that can identify the talk group. I'm trying to learn that.
budevans
Member
P25 Trunk systems are not scanned. The system controller (a computer with a database of Frequencies, Talk Groups and User ID's belonging to the Talk Groups) keeps track of frequencies in use and those that are available. When an affiliated radio's mike is keyed, the system controller assigns the least used available frequency to the Talk Group.
No. Your scanner either receives directions from the control channel or it doesn't. It's that simple. Again there is no scanning in the process.
They are wrong.
You are barking up the wrong tree. In the simplest terms two things have to happen to receive a Talk Group on a P25 Trunk system. First the Control Channel sends data saying that a Talk Group has been assigned to a frequency. The second part happens with your scanner. If it has the Talk Group then it receives it. If it doesn't have the Talk Group, then your scanner ignores it.
Only Conventional Frequencies are Scanned, which means your scanner must look at each Conventional frequency for a period of time to see if it's active. So scanning Conventional Frequencies is time consuming where as P25 Trunk Systems are in human terms instantaneous.
Last edited:
Ubbe
Member
TRX scanners scan the voice channels. It decodes the datainformation in the voice channels that tells what TG it is and color code and a lot of other things like what other TG's are active in the site, to be able to use preempted priority TG monitoring.
TRX only checks those voice channels that have a carrier and have a voice conversation and it will take some time to sync to and decode the data to determine if it is a TG that have been programmed in the scanner for monitoring, I think worst case 360mS for both DMR and P25, so 3 ACTIVE voice channels with voice conversations on a site will have a scan cycle time of 1 sec in the hunt for other TGs that should be monitored.
When a user release his PTT, and the system have been setup to have the users go directly to the control channel "transmission trunking", a Uniden scanner will have no delay when picking up the next PTT. A TRX scanner will have a worst case of 1 sec, in the example above, until you will hear that user again.
That's the reason for a Uniden scanner to be more suitable on busy systems where you have many conversations taking place at the same time. In less loaded systems and fewer channels per site or systems that have been setup to have users sitting on the voice channel during the delay time "message trunking", the TRX in my opinion works better than Uniden.
/Ubbe
TRX only checks those voice channels that have a carrier and have a voice conversation and it will take some time to sync to and decode the data to determine if it is a TG that have been programmed in the scanner for monitoring, I think worst case 360mS for both DMR and P25, so 3 ACTIVE voice channels with voice conversations on a site will have a scan cycle time of 1 sec in the hunt for other TGs that should be monitored.
When a user release his PTT, and the system have been setup to have the users go directly to the control channel "transmission trunking", a Uniden scanner will have no delay when picking up the next PTT. A TRX scanner will have a worst case of 1 sec, in the example above, until you will hear that user again.
That's the reason for a Uniden scanner to be more suitable on busy systems where you have many conversations taking place at the same time. In less loaded systems and fewer channels per site or systems that have been setup to have users sitting on the voice channel during the delay time "message trunking", the TRX in my opinion works better than Uniden.
/Ubbe
- Status
Similar threads
