PSR-800 confusion with multi-site workaround

[bfletcher]

Greetings,

I am new to the PSR-800. For several days I've been attempting to grasp the workaround for its lack of multi-site capability but need some further clarification if I may trouble you.

My county [Preble in Ohio] has seven sites within the Ohio MARCS system and by default it downloads 288 talkgroups. I've duplicated that system to yield seven systems and deleted the extraneous sites, resulting in only one site per system. I'm not aware that I have any confusion up-to that point, assuming that it's okay for me to accept the system and site defaults.

I become confused at the stage of working with the talkgroups and creating scanlists. Corresponding with my number of systems I created seven scanlists. Then, because of a lack of knowledge I've attempted several methodologies but without good results. Those attempts range from keeping all 288 talkgroups in all of the systems/sites to deleting many of them in each system/site. In that instance, from within each system/site I tied the talkgroups to just one scanlist. In another attempt I deleted the talkgroups from all but one system/site and tied them to all seven scanlists (though in my feeble mind that doesn't seem right since in the scanlist tab the system field shows just the one site in each scanlist). I tried that method because of a post I read suggesting it is not necessary to duplicate talkgroups across various system/sites but I may easily have misunderstood what was written.

Another source of confusion is that whether I keep all 288 talkgropups or delete all but approximately 25 the scanner takes several times longer to complete a scan than what is the case if I don't split the system. But I am also scanning all of these newly-created scanlists. If that is not the prescribed method and if I'm supposed to manually choose just one of these scanlists then I'm left wondering why it is not acceptable to allow the radio's built-in roaming methodology keep control. I suppose I'm also interested in knowing whether the scanner sweeps through each talkgroup on a scan cycle, or if it only sweeps through the handful of frequencies from each site.

I'd be grateful for any clarification on this.

[brian]

To answer your second question, the number of talkgroups you're scanning does not have any effect on the length of time it takes to scan through on "pass." The time length of one pass is determined by the number of trunked systems/sites you're monitoring along with the number of conventional channels in active scan lists. To reduce that time, reduce the number of sites and/or conventional objects.

Regarding your talkgroup question, you would typically want to program the talkgroups that are active on a particular site into the Trunked System Object containing the frequencies for that site. Ohio MARCS is a huge system with many talkgroups, but not all of them will be active on each site. There are probably some talkgroups that are carried across all sites on the system, some talkgroups that are regional and carried on multiple sites in a region, and some talkgroups that are only carried on a single site. How to determine which talkgroup is carried on a particular site is tricky. You can program all talkgroups into all Trunked System objects and pay careful attention while monitoring to see which talkgroups are active on a particular site. Or you can try to use a trunked system decoding application (like Unitrunker or Trunk88) with your radio to monitor each site for some time and create a list of active talkgroups.

Since the memory structure of the PSR-800 is virtually unlimited (based on the capacity of your MicroSD card), I'd say leave all talkgroups programming into each Trunked system object. I'd also add a wildcard to each Trunked system object, which will allow you to hear active talkgroups that you have not programmed (among those default 288). At minimum, I'd associate all talkgroups from each site in a scanlist dedicated to the site. This would allow you to control which site or sites you are listening to at any time by enabling or disabling that scanlist.

You might find that you want to separate groups of talkgroups from within each site into separate scanlists - for example, Law talkgroups in one scanlist, Fire talkgroups into a second, EMS talkgroups in third, State talkgroups in a fourth. This would mean you'd have 4 scanlists x 7 sites/Trunked System Object = 28 scanlists in use. You have 200 scanlists to work with in a single configuration This provides more control over what you listen to.

You could then group each of those 4 scanlists associated with a particular site/trunked system object into a Scan Set. A scan set is a set of scan lists. This allows you to enable or disable a group of scan lists in one operation.

Make sure you label your Trunked System Objects and Tower sites in a way that indicates which system/site you're listening to at any given time. Also label your scan lists accordingly. Change from Basic (or is it Simple?) Display format to "Advanced" or "Expert" so that you will see more details about what you're hearing.

Hope that helps clear it up a little bit.

[jackj]

Brian has given a very good explanation of how the Ohio MARCS TRS works. You really don't describe exactly what you are trying to accomplish by splitting up the sites and talkgroups so I'm not sure if I'm answering your question(s).

Your 800 monitors the decode error rate of the Control Channels and when the error rate gets too high, it looks for a CC with a better error rate. So you could set up a system with all 7 towers and 288 talk groups in it. That would allow the scanner to pick the strongest (lowest error rate) CC and you would automatically be monitoring the strongest tower. But you would hear all the county's traffic.

By setting up 7 systems, you are forcing your scanner to monitor the same info on 7 different systems, assuming all 288 talk groups are on all 7 towers. This will slow down you scanner to a little less than 1/7th of it's speed on one system.

If you want to segregate the different agencies and only monitor one agency at a time but still be able to switch to other agencies, then setting up different scanlists or scan sets is the only way to go. But put all 7 CCs in each. But remember that when you have more that one active, it will take your scanner longer to scan through the lists.

[troymail]

As Jack stated, understanding what you are trying to do is important... mostly to determine if what you are doing is really necessary.

Having said that, I have been learning about/experiencing new "site based" systems in my area as new P25 systems rollout replacing legacy analog simulcast systems. The simulcast systems broadcast all talkgroups across the entire system/county but the newer "site based" systems in my area (and probably yours) don't.

Now, add to the situation is the LSM/CQPSK modulation issues which scanners currently have trouble handling which means the radio may be losing lock on the CC and spending alot of time searching only to find the same one again - or possibly for a brief time, a remote/different site that may or may not be carrying the same activity.

To overcome these issues, I've been doing some custom programming as well which starts with importing the entire system and all sites into EZ Scan.

From there, I usually try to trim the list of frequencies down to only the primary and sometimes one alternate CC frequency for each site using the frequency lockout function (note that this speeds up the lock onto a CC frequency since the radio doesn't need to search across all frequencies for the site before locking or giving up). In the simplest form, I assign all of the talkgroups for this "system" to a single scanlist and call that scanlist "all sites".

Next, I duplicate the system, and now lock out all but one "site", assign all talkgroups to a new scanlist, and call that scanlist "site XXX".

I repeat the duplicate and site lockout process for as many sites as I want to be in control of.

This process ensures that all of the sites and only the sites I want to try and listen to are being checked/scanned while those more distant sites are ignored (again, speeding up the scan process).

Aside from the manual programming, the biggest downside to this is that you have to maintain the talkgroups across all duplicated systems and scanlists since the talkgroups are assigned to a scanlist which are assigned to a specific copy of the system. This gets more complicated if/when you create more than 1 scanlist for each copy of the system.

The radio is designed to simplify things for the novice user ... but that doesn't mean you can't tweak things to what you want or need.

Last week I was in Key West and did a direct import into the radio (without being selective on which sites to load) which worked fine in most cases. I actually wanted to see what happened with the sites (would I get more than just the Key West site, etc). I did occasionally see the radio locking onto different sites. I think in some cases I was picking up activity on a more remote site which the radio was having trouble holding the voice frequency. If the radio had stayed on the closest site, reception would have probably been better.

I like having the control.....

Edit: of course, none of this is necessary in real "subscriber" radios. While our scanners are passive and just receive, subscriber radios can jump around from site to site (in most cases) and affiliate with the system's sites since their radios transmit data on their own. Wouldn't it be cool if our scanners could "affiliate" in a similar fashion (that comment will surely cause some discussion here!)

[troymail]

I just looked closer at Ohio MARCS - Multi-Agency Radio Communications Trunking System, Statewide, Multi-State - Scanner Frequencies and I only see a single 4 frequency site for Preble County. Did I miss something?

??

[bfletcher]

Thanks for your replies. My limited understanding comes from reading pieces of information from a large pool of information here on the web, suggesting that the PSR-800's "roaming" methodology (for lack of a better term) could lead to missed transmissions where a true multi-site configuration would not. When I import MARCS from here on RR it yields seven sites, one of which is very close to my home location and others expand farther out. I was under the impression that—for example—a mobile emergency unit's transmission may potentially be sent from any one of those other sites and if the PSR-800 is "stuck" on the West Alexandria site nearest me then I may not hear the transmission. I further convinced myself that this was a possibility when I was mobile with this radio a few days ago and I heard communications both from the West Alex site and also heard other communications from the New Madison site, which was nearer while I was traveling. Hence came the impression that maybe I should try splitting the seven sites among seven systems. I listen both at home and on the road while commuting throughout the county. Brian

[troymail]

Given your description, I assume you did a zip code or county (locational) import - and that's how you got 7 sites -- is that correct?

In theory, I believe that if you were very close to any one of those 7 sites, the radio would always just lock onto the CC for that one site and never check the other sites. If you move around/go mobile, the radio could switch to a different site (which may or may not have the same activity on it).

I further believe the only way to ensure you check *all* sites of interest, you must program each "site" as a separate "system". This is really only important is the activity you want to hear is isolated to one site or another -- but that's something you have to figure out.

To see how things are really working, you can try a couple of things:

1. Set the display settings in EZ Scan to "Advanced" (under general setting tab) and also set Line 4 of the display to "System and Site Name" (under the Advanced Features tab). When talkgroups are active, you can see which site is being tracked (does it change?).

2. Another option - set all talkgroups to record and then when you copy the audio from the SD card to your PC, it will show you which site(s) the activity/talkgroup was captured on.

[brian]

To the OP -

You're right. You may listen to one site and the transmission you want to hear is carried on a different site. That can certainly happen if you leave all 7 sites as part of a single Trunked System object. As mentioned, the "Roam" feature will try to determine the best site (based on the threshold settings, which can be adjusted) and monitor only it until such time its decode rate falls below the Low threshold setting. If the transmissions you want to hear are not carried on that site, you won't hear it.

If you duplicate the Trunked system object 6 times, and wind up with 7 Trunked System objects each with a single, different site, then you can scan any combination of those 7 on each pass, depending on how you set up your scan lists. As mentioned, scanning 7 sites on each pass takes a bit of time, and you may very well miss your transmission if it is carried on a site and your scanner is busy scanning other sites.

You need to determine, with some trial and error monitoring, which site or sites carry the talkgroup transmissions you want to hear, and monitor those. If all sites carry your transmissions of interest all the time, the only monitor the closest site. If only one site carries it, then that's your site, near or far.

Good luck.

[bfletcher]

Thanks for the continued feedback. Presently, I believe I may be able to narrow down to 3 sites. To explore the prospect of splitting those 3 into separate systems, should I place all of the desired talkgroups into each of the 3 system/site combos? And can I let the talkgroups remain in their originally downloaded scanlist locations since the objective is to scan all of the sites?

And I apologize but I am still confused about how the radio treats systems during a scan pass. Since the required time to complete one pass increases significantly when multiple systems are created does it look at every talkgroup? Rather, do I reduce system resources if I delete undesirable talkgroups? Thanks.

[troymail]

Scan time is based primarily on:

a. the time it takes the radio to lock onto a CC frequency - and-
b. the number of talkgroups you have that are "active"

If the system's control channel is solid/strong and there are no "active" talkgroups of interest, it takes 1 second or less to check that system before the radio moves on the the next system or conventional frequency.

Having said tat, if you have 5 systems programmed and active, under the same scenario, it will take about 5 seconds to cycle back around to the first one.

All times increase if the radio has trouble locking onto a CC frequency and/or the radio stops on active talkgroups.

Experiment with it (that's part of the hobby!) -- in a stationary (home or office) test, try this:

Create one VFolder with all (3? 7?) sites loaded with the default import/load.

Create a 2nd VFolder where you only load the closest site.

Try each for a while -- do you notice any difference?

[brian]

In my experience, the "b" portion of the above message is doesn't hold true.

I have have a Trunked system object with 1 talkgroup and a trunked system object with 300 talkgroups all in active scanlists, and the amount of time the radio spends sampling the control channel will be the same, about 1 second.

If you're scanning 7 different trunked system objects, it's going to take about 7 seconds or so to scan through, assuming none have any scanned talkgroups active. That's a long time, in my opinion.

Combining the 7 sites into a single trunked system object guarantees that you'll only scan 1 site on each pass, which helps with scan time, but you don't have control over which of the 7 sites is scanned on any pass.

I have noticed that if you try to scan a trunked system object with multiple sites that is out of range of the radio that it takes a good while for the scanner to scan through all sites looking for an active control channel. This is a drawback of the location-based programming method - depending on how the geotag data is entered for the site or system that was imported, the scanner may be trying to scan an out-of-range system and the radio may seem to be malfunctining. Look for the steady "T" in the display when scanning - this will give an idea of when the radio is locking on to an active CC.

[jackj]

There seems to be some confusion about how a scanner scans a trunked system.

According to my understanding, the scanner isn't scanning for active talk groups on the voice channels. In fact, it isn't scanning at all, it's monitoring the data stream on the control channel. If a member of a talk group request a channel, a frequency pair is assigned to that talk group by the controller and the controller adds that frequency pair assignment and TG number to the data packet it transmits on the control channel. All members of that TG then switch to the assigned VC. So your scanner is listening to the data sent on the CC. When it hears a TG it is interested in, it switches to the VC frequency pair that TG has been assigned. So the number of TGs you have entered in your scanner does not effect the 'scan speed' of your scanner.

Your scanner treats the systems you have programed into your scanner as completely separate systems even if the only difference is the TGs. If you have a system with only fire departments TGs in it and another with only PD TGs and your scanner hears a PD TG while it is monitoring the FD system's CC, it will ignore that TG. It will then switch to the PD system, load the CC frequency, wait for the beginning of the next CC data stream and then listen for the PD TGs you want to monitor. So two identical systems will take about three times as long to scan as one system.

The time it takes to cycle through all the CC data is really the only hit you'll take by splitting TGs into agencies. If this time hit is acceptable to you then there is nothing wrong with splitting them.

[troymail]

Originally Posted by brian

In my experience, the "b" portion of the above message is doesn't hold true.

Perhaps my statement wasn't clear. "active" means the talkgroup is programmed in the scanner *and* when the CC is checked, someone is talking.... This will certainly delay getting to the next talkgroup or system.

I have noticed that if you try to scan a trunked system object with multiple sites that is out of range of the radio that it takes a good while for the scanner to scan through all sites looking for an active control channel.

This is certainly true -- as I understand it, the radio will lock onto a CC and then on the next check it remembers that CC frequency and starts there with the assumption that it will still be active. If it finds that it is not or the signal isn't good enough, the radio will then start searching through the list of frequencies programmed in your scanner looking for a good CC signal. With many, many sites and site frequencies programmed, this could take quite a while.... On the other hand, it may find a different CC on a different site and in some cases, result in the user hearing the same of different activity depending on how the actual system works.

With regard to one site vs. another, one of the the systems I am listening to at my location has two sites that I can receive well. There is completely different activity on the two sites (with some overlap). Therefore, if I lock onto one site or the other all of the time, I will miss activity on the other site. Even worse, if the radio switches from one site to the other (back and forth) because it thinks different CCs on different sites are active from one CC check to the next, I will get alot of "fractured" conversations... this can also lead to people thinking the radio isn't working correctly. When I program the two sites as two different systems, I ensure that both site CCs are checked everytime.

Edit: oh - and I also limit the frequencies to either only the CCs or in some cases a single CC frequency (in cases where I've found the CC almost never changes). This helps ALOT. Of course, this runs the risk of going deaf if the CC does actually change and I don't have it programmed. It's a choice....

Having said that - all systems are not the same -- you have to determine that for yourself for the system(s) and site(s) you want to listen to (one size does not fit all).

[balibago]

I have a psr 800 and beleive me I don't trust it. I bought this radio because it has a recorder, it can do Phase2 APCO,and has a discriminator output {a lot of mischief can come of this}. But it acts strange on those multi site systems. I think you have to treat it like those old 200 channel scanners-don't try to program too much in one scanlist. LWIN has almost 2000 talkgroups and 100+ towers. I put them all in one scanlist and that talkgroup is useless. You need to put only a few towers and 100 max. TGs in a scanlist. The Bearcat format is superior in my opinion.

[doc832]

This may be too simple of a question, but I am in the same situation. When you have your trunked systems do they all show in the trunked area no matter what scan list you are programing? I am trying to put different systems on different scan list and have failed terribly.
Thanks for the information as i am slowly understanding this. The guy at the radio store makes this sound so easy and it is NOT. I believe he has no clue how to use the software either.

[troymail]

The 800 (and Uniden's HP-1) attempt to simplify listening for the novice user. The theory is that you don't need any special programming - just import and go. That works for the casual user. But like I said earlier - they are so many variations to the systems, one size just can't cover everything. That why EZ Scan gives you the ability to do manual programming. However, in order to do that manual program, you first need to decide if you really need to and if so, there is some learning and understanding that needs to occur. Sure, this can be frustrating - but there is no getting around that. Have you ever played a sport? Did you know how to play the very first time? No - it took time. So give it some time....

There really isn't anything wrong with the scanner(s) -- the scanners are trying to do things with (receive) these systems but the scanners were not part of the design when the systems were created. So, we have to "make adjustments" to maximize our ability to listen.... just part of the hobby.

If you had a real subscriber radio in your hand you would have spent a ton of money - alot more than you paid for your scanner. Sure, that might work better but most likely only tuned to a single talkgroup on a single system (not scanning many systems and talkgroups). Additionally, if it were a real subscriber radio, the radio would "affiliate" or "connect" to the system and it's sites as you move around - automatically - but that's only because it is transmitting - your scanner is not. On the transmitting subscriber radio, if you were to move out of one site and into another, the "system" will connect the two sites so users on both sites hear each other. When that radio returns, the sites disconnect (assuming it was the only radio on the 2nd site) and now the activity on the 2nd site goes away.

There's alot to learn - but it's part of the fun of the hobby!

[bfletcher]

I thank each of you for your insight. While exploring various configurations---and grasping the pros and cons of each---would it be acceptable to utilize the skip and/or lockout functions at the system, site, and site frequency sections, or must I delete those items in order to explore? Brian

[brian]

You can "skip" scannable objects - conventional channels and talkgroups - from the radio itself. You cannot skip trunked system objects or sites from the front panel of the radio. In my opinion, this is one of the major "features" that was dropped from the PSR-800 to make it a "easy to operate" scanner.

The advantage to separating a trunked system with multiple sites into multiple trunked system each with one site is that you can then assign talkgroups associated with a single system/site to unique scanlists. This allows you to activate or deactivate those systems/sites from the active scan configuration easily. Using software, you can lock out systems and sites, but I see very little use in that. I suppose if you're importing and don't customize your configuration and just want to eliminate a site, it's useful.

[mlmummert]

Not to hijack but can you make the scanner scan all active control channels on one system?


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