trunking help

[k8erw]

I am working on gathering used equipment to put together my own trunking repeater. What I need to know are the specifics on what is actually needed. I have 3 Motorola quantar repeaters and a Motorola trunking controller. This is going to be a single site system. What else am I missing? Any information would be greatly appreciated. Thanks

 

[rescue161]

What type of trunking controller do you have? i.e., 6809 SmartNet/SmartZone, LTR, etc. Are you planning on having dispatch terminals? Are you using encryption over wire-line? Lots of different systems out there and they are all different.

 

[k8erw]

It's a Motorola smartnet/smartzone controller. Motorola cpx2000 model . Not gonna have a dispatch center. Just gonna be between our trucks, dispatcher and the bosses. We just want to have a handful of talkgrouos to start.

 

[rescue161]

Not sure if the CPX2000 uses the 6809 chip, but if it does, you will have a hard time convincing Motorola to create a new system and burn a new chip for you. What band are you planning to use this on? If it's VHF or UHF, the configuration of the controller will be more involved than on 800/900. It is not a simple plug and play thing.

If the dispatcher is just going to be using a mobile radio, then you will not need a CEB. That is a headache and a half on a trunking system as there are many more cards involved vs a conventional CEB.

On our old UHF trunking SmartNet system, we'd get updates from time to time from Motorola on a new 6809. I had the build sheets on our old system, but I think we destroyed them. They included things like the channel number, TX/RX frequencies, base calculation, offset, control channels, the rotation of the control channels, the failsoft data, etc. Ours was MUCH older than the CPX2000 and was installed in 1992. It had two controllers for redundancy and used a T-Bar to switch between the controller if there was a failure of either one. We removed it in 2015 and I'm glad we did. It was a pain to keep running. Parts availability and support from Motorola was almost non-existent. Most of the people at Motorola didn't even know what we were talking about when we called and asked for flat-rate repair on a TIB or any other card. It was a very robust system, but it was old and started to become flaky in its final years. Chasing voltages on the backplane of the controller to the faults was a common thing and as time went on, more and more micro-cracks were forming on the backplane traces, making for intermittent problems that were hard to track down. Motorola engineers cautioned us about powering the unit down as when the backplane cooled, the traces on the backplane would shrink, causing the micro-cracks to become larger. They told us that if we powered it down for more than an hour, then it would probably never work again. They were right.

 

[rescue161]

It would be much cheaper to go with DMR trunking system and you'd have warranty support. If you put up two repeaters, you'd have 4 talk paths and depending on the amount of users, you may not even need trunking. If you implement RAS you wouldn't have to worry about pirates.

 

[Project25_MASTR]

Not sure if the CPX2000 uses the 6809 chip, but if it does, you will have a hard time convincing Motorola to create a new system and burn a new chip for you. What band are you planning to use this on? If it's VHF or UHF, the configuration of the controller will be more involved than on 800/900. It is not a simple plug and play thing.



If the dispatcher is just going to be using a mobile radio, then you will not need a CEB. That is a headache and a half on a trunking system as there are many more cards involved vs a conventional CEB.



On our old UHF trunking SmartNet system, we'd get updates from time to time from Motorola on a new 6809. I had the build sheets on our old system, but I think we destroyed them. They included things like the channel number, TX/RX frequencies, base calculation, offset, control channels, the rotation of the control channels, the failsoft data, etc. Ours was MUCH older than the CPX2000 and was installed in 1992. It had two controllers for redundancy and used a T-Bar to switch between the controller if there was a failure of either one. We removed it in 2015 and I'm glad we did. It was a pain to keep running. Parts availability and support from Motorola was almost non-existent. Most of the people at Motorola didn't even know what we were talking about when we called and asked for flat-rate repair on a TIB or any other card. It was a very robust system, but it was old and started to become flaky in its final years. Chasing voltages on the backplane of the controller to the faults was a common thing and as time went on, more and more micro-cracks were forming on the backplane traces, making for intermittent problems that were hard to track down. Motorola engineers cautioned us about powering the unit down as when the backplane cooled, the traces on the backplane would shrink, causing the micro-cracks to become larger. They told us that if we powered it down for more than an hour, then it would probably never work again. They were right.

I really subscribed to this thread for this.

I actually just finished an install of a Connect Plus system at a site which still has an active 800 MHz Privacy Plus system on a 6809 controller. The control channel has been online continuously since 1997. The system is made entirely of MSF5000 and Micor repeaters. Still has about 600 subscribers who refuse to migrate to digital on it.


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[rescue161]

That's funny. When I pulled the plug on ours, it clacked over to the secondary controller, so I pulled the power to that one. The T-Bar had a fit, clacking back and forth before the controller realized it wasn't going to work, then it went into Failsoft and that's when I heard a LOT of users arguing with each other to get off of their channels/frequencies...lol I then told them that they needed to change zones on their radios to the new system as I was powering down the one that they were currently using. They started yelling at me to get off of their channel, so I just pulled the power to each repeater until all 10 were offline. Once it got down to the last repeater, I made the final announcement on the system as a last ooh-rah for the old "2808" System ID. I recorded the historic event (LOL) but don't know what happened to the audio.

We had a mix of Quantars and MSF5000s, secure wireline cards to feed encrypted audio back to the CEB for the dispatch consoles and a ton of spare cards that we started repairing when Motorola stopped servicing them. I am SOOOO glad that I don't have to dial into the controller anymore to find out the faults and then dig through a bunch of manuals to figure out what all of those faults mean. It was fun, but it got old real fast. There was more than once that I got called to the tower late at night for one problem or another.

 

[kayn1n32008]

... Still has about 600 subscribers who refuse to migrate to digital on it.

Do they have any analogue options where you live? If not, give them a date that the system will be shut down, and tell them they can migrate to the DMR system, or put up their own system. If they play chicken, don't blink. Kill the power at 00:00 on the date you gave them. Why should you have to maintain an ancient system because they don't want to migrate.

 

[mmckenna]

It was a happy day I tore mine down, got tired working on it. MSF5000's wandering all over the place, needed constant maintenance.

K8ERW,
Hope you didn't pay a lot for that thing. The likelihood of it coming back to life is probably pretty low. Trying to piece the system back together and make it all work right sounds like a huge headache.
I'd listen to the guys saying this might be a loosing proposition.
You might be better off with just a conventional system. If you have enough traffic that you really do need trunking, check into an LTR system. New controllers are relatively inexpensive.

 

[k8erw]

Well, it is going to be an 800mhz system was the plan. We definitely want a trunking system of some sorts. but with it being 800mhz are my options limited on what kind of trunking repeater we can out together?

 

[KevinC]

Well, it is going to be an 800mhz system was the plan. We definitely want a trunking system of some sorts. but with it being 800mhz are my options limited on what kind of trunking repeater we can out together?

I would think getting licensed at 800 would be an issue...but I could be wrong.

 

[kayn1n32008]

You can get 800MHz DMR repeaters, and subscribers from Motorola. A pair of DMR repeaters, and connect plus trunking will give you plenty of capacity. All will also be supported may Motorola as well.

I'm not sure why you want to play around with ancient type 2 Smartnet crap. You will have zero support from Motorola, the repeaters are not supported, and neither is the controllers. Plus the XTS/XTL series of radios will not be supported for much longer either. At least with DMR you are not being gouged as bad as with Type 2 gear.

Having said that, have you applied for any frequency pairs yet?

 

[Project25_MASTR]

Do they have any analogue options where you live? If not, give them a date that the system will be shut down, and tell them they can migrate to the DMR system, or put up their own system. If they play chicken, don't blink. Kill the power at 00:00 on the date you gave them. Why should you have to maintain an ancient system because they don't want to migrate.

Long story short, my shop was contracted out to install an airtime system at this site (800 MHz Connect Plus) from an "air-time" carrier. The site owner has the Privacy Plus system running. He is looking into selling the system but not the site/tower 1500 footer that's nearly 1800 feet above average terrain…even Motorola told the city they had to have access to the site for their county wide simulcast Astro 25 system (also 800 MHz). The "air-time" company seems to have the interest and the money, they are considering purchasing the Privacy Plus system…so I'm not currently responsible for maintaining it. However, if I were to be responsible it would be similar to our old Privacy Plus system we had in another city…if it breaks, you are SOL so start getting ready with digital capable radios.

You can get 800MHz DMR repeaters, and subscribers from Motorola. A pair of DMR repeaters, and connect plus trunking will give you plenty of capacity. All will also be supported may Motorola as well.

I'm not sure why you want to play around with ancient type 2 Smartnet crap. You will have zero support from Motorola, the repeaters are not supported, and neither is the controllers. Plus the XTS/XTL series of radios will not be supported for much longer either. At least with DMR you are not being gouged as bad as with Type 2 gear.

Having said that, have you applied for any frequency pairs yet?

I checked pricing on an XRC9100 a few months ago…still listed at $40,000. With Capacity Max being significantly less, I don't know why anyone would currently install a Connect Plus if they need less than 17 sites (unless they just have that many first gen XPR's they need to use).

Our "air-time" customer is still learning and as we try to guide them, they still want to do what they want to do. For example at this site I just installed, not 2 feet away is the competitor's Connect Plus system (which is already linked at 5 sites) and they felt the need to use the same antenna system and not link their initial two sites…they also feel the need to upgrade the Capacity Plus air time they purchased off of us in other cities to Connect Plus.

Capacity Plus is fair if you need a low cost trunking system (~$5,000 per repeater for a single site system)…I believe that was what you were getting after.

 

[kayn1n32008]

Shoot. Capacity plus. Not connect plus. The LTR distributed type one, not constant control. Apologies. Heck even a Hytera sudotrunk would likely be enough for the OP needs.

 

[mmckenna]

Well, it is going to be an 800mhz system was the plan. We definitely want a trunking system of some sorts. but with it being 800mhz are my options limited on what kind of trunking repeater we can out together?

Do you have licenses for those 800MHz pairs yet?
-Talk to a frequency coordinator before buying anything.

What's your reasoning behind needing trunking?
-Do you really have that many users that channel capacity is an issue?
-Or is access control a concern?

You can run any kind of trunking you want (within reason) on your frequency pairs. The concern should be getting equipment. While buying up lots of used 800MHz SmartNet equipment might seem attractive, you're buying into 1980's technology that is no longer supported by the manufacturer. You'll be limited to Motorola or EF Johnson radios.
I shut down my 800MHz SmartNet system back in 2013 or so, and most of it went to the e-waste recyclers. The repeaters were junk. The controller had so many leaky capacitors that there was no way it was going to work again. The old MTS-2000's were selling for about $20 on e-Bay, so we didn't even try to sell them. It wasn't worth our time or effort for $20 each. Most of the mobiles were in halfway decent shape because the old Spectras had been replaced under the rebanding project.
You also have to be careful of the older radios you'd buy used. Not all of them have been rebanded, so you could easily run into issues there unless you were 100% confident that what you were buying had been rebanded.

There are better options.
-DMR, as suggested, can run two talk paths on one repeater. There is access control. For 800MHz, you are going to be limited to Motorola gear, but be aware that can get expensive. Be careful about getting locked into a brand. Dispatchers can link into the repeater via the data network, so they could be running off a PC. Automatic Vehicle Location and data communications are all options. Repeater linking over IP to increase coverage.
-NXDN will do one talk path on a repeater. There is access control. Tends to be cheaper than DMR. On 800MHz, you'll get locked in to Kenwood. PC based dispatch consoles are cheap and don't require a radio if you have a network connection to your site. Automatic Vehicle Location, data transmission, etc. are options with this. Repeater linking over IP is an option to increase coverage.
-LTR opens things up a little bit more. Would be cheaper. Older technology but still used. Can still do AVL and data communications.

Avoiding the brand specific systems can keep pricing down. LTR to DMR (not MotoTrbo) might be a better way to go. You can still buy used equipment as well as get new stuff.

Also, while I understand the desire to save money and do it yourself, you should at least compare prices with a radio shop that will sell you air time on their system. Often they have linked repeaters and the coverage you'd get would be much bigger than a single site of your own. You would pay for air time and/or by subscriber, but not having to build your own system, lease tower space, licensing, frequency coordination, etc. can really make it an attractive option.

 

[Project25_MASTR]

Some of the DMR manufacturers repeaters systems were actually designed by someone with a networking background and as a result, have ID based white and black lists for access control. Unfortunately, those features aren't as common for 800 MHz solutions.


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[rescue161]

…if it breaks, you are SOL so start getting ready with digital capable radios.

This is exactly what ended up happening with our system. It was a 10 channel SmartNet that when I turned it off, only 4 channels were operational (control channel and three voice paths). We had accumulated about 15 spare MSF5000s and were swapping parts and doing repairs on a weekly basis. The controller can present errors that look like they point to the repeaters, but some of our problems indicated bad dummy loads on the combiner and others were from the micro-cracks on the back-plane of the controller. I became real friendly with the controllers service manual(S) and tracing down TACB & TIMI as well as many other errors.

Our new system was installed and operational, so we started migrating users over, but some did not plan ahead and purchase radios that would work on the new system. So we were told to keep the old system alive until everyone was able to migrate. Well, you tell an end-user that they can still use their radio until the cut-off date and they will not buy a new radio and will complain when you tell them that the system is being turned off. We went through 3 kill-dates. It would get down to the wire and then we'd be called off because someone else didn't plan ahead. It got to the point that we couldn't keep up with the maintenance due to parts availability, nor could we power down the system to repair the controllers (nor would I have wanted to), so we ran with the idea that if it died, it was dead and that it would help those that didn't help themselves to buy what needed to be bought to get onto the new system. Those 4 channels staggered along and made it to the final cut-off date when I pulled the plug(s) and still heard users on the system. We knew who they were and their radios were programmed for the new system. I don't know why they refused to chop over.

That was in 2015. We still have people that come to the shop and say, my radio is not working, then they hand us a Systems Saber or take us out to their vehicle and show us Syntor.

 

[rescue161]

How many talkgroups and/or users are going to be using the system?