MOTOTRBO is the professional grade radio line from Motorola Solutions. Motorola Solutions is not be confused with Motorola as the two companies split 10 years ago with the cell phone side being bought by the Chinese. The Solutions side focused on Motorola’s roots, which is Two-Way Radio Systems. There are multiple frequency bands within the MOTOTRBO line up, however the primary frequency band is UHF and all brand new systems are generally UHF. VHF is considered mostly legacy and is normally used with an existing customer that often has existing VHF equipment. Radio frequencies can’t be mixed with MOTOTRBO. VHF is not used that much anymore and at least in our area has a lot of interference due to poor coordination by the FCC.

I’ve been in numerous situations where “coordinated” VHF frequencies are used by my own customers right next to each other. It is very rare to have a completely clean VHF frequency in an urban area and interference generally reduces the coverage by at least 50%. Because of that we always check any frequencies on the ground before we buy them from the coordinator. The obvious longer term problem is having any random radio provider get a coordinated pair that overlaps with your customer and all of a sudden you get “the system isn’t working” from your current customers. As you can surmise, these types of problems are very difficult to fix. So in our case, we would only do new VHF in a rural area where distance matters. Otherwise it’s all UHF and possibly 700/800 Mhz.

MOTOTRBO systems

MOTOTRBO comes in many flavors with many features. Motorola Solutions loves charging for incremental features which brings me to one of my biggest pet-peeves. New features often times require a duplicated code plug. For any given customer that has a mixed fleet, you can have multiples of the same code plug because one feature is added that the customer wants on those specific radios that is not supported on older radios. Radio Management is supposed to help with that, but it’s poor design means that the average technician just gets lost trying to master it. Just a note that the author (me) of this article is a software engineer who learned MOTOTRBO from scratch and has deployed dozens of systems.

MOTOTRBO systems are broken down into types – analog single repeater sites,  digital conventional sites, IP Site Connect Sites, Capacity Plus Site, Linked Capacity Plus Sites and Connect Plus. The first 3 I consider inferior to the latter 3 for a bunch of reasons to long to discuss here. I want to focus on the Linked Capacity Plus sites as they work for the majority of MOTOTRBO customers.

MOTOTRBO Linked Capacity Plus

Linked Capacity Plus is a trunked system with multiple sites that are linked together over a computer network. Trunking is the concept of having multiple repeaters pooled together like a server farm at one site and sharing their resources for the radios using that site. It uses an algorithm to share the radio spectrum in the most efficient way and because of this, makes it superior to any digital conventional, IP site connect or analog system. You can double or triple your capacity using the algorithm using the same frequency. If you saw before how difficult it is to get clean frequencies, it’s always better to use more of a quiet one than to have too many which can create random coverage problems that average techs are never going to figure out. One thing to note is that average radio technicians often don’t understand computer science well enough to deploy these linked systems. I’ve seen some real desperation in some of my competitors screw-ups when trying to deploy them.

The key to a successful Linked Capacity Plus implementation is planning and benching. One really bad habit that traditional radios techs do is make programming and design and afterthought because they concentrate too much on the antenna design. You can not have a successful LCP deployment programming it in the field. You need to bench these systems in house using switch equipment that emulates the customer environment exactly, right down to the IP addresses and VLANs that separate the sites.

LCP Site Selection

So the very first thing you do when planning for LCP is site selection. Often times you can use computer modeling to determine what sites work, however as I previously mentioned, that only works well if you trust the FCC coordination because the coverage maps could be off by as much as 50% with interference. Interference on Digital is hard to figure out, but you can certainly get an idea by looking at the noise floor of a trunk at rest using RDAC. I like to pick the sites and then use pre-coordinated frequencies or some combination of current customer frequencies to really check the coverage using a temporary single repeater trunk. This will tell you for sure if you have problems. I had one case with VHF where one frequency had so much interference that I got may a mile of reception with it and bunch of key-up problems, but the exact same set up with a quiet frequency and it was 7 miles – in a very urban area with military. So interference matters for site locations and frequency picking.

Once you pick the sites, the next step is to make sure the IT department is engaged with right away. Nothing will make an LCP implementation fail faster than having the IT department find out about your requirements for networking after the equipment has already been ordered. I keep the most important information needed for IT in a standardized spreadsheet that I’ve tested over many projects. As long as that information is accurate and shared with the right people, I don’t forget important details that will de-rail the implementation. Once you have all of that and bench the whole physical system, you can start to build out the subscriber code plug.

Subscriber Code Plugs

Subscriber code plugs are the most time intensive and difficult part of the LCP system. There are a lot of concepts, such what the channel pool should look like, what VL mean, how sites are determined, what roaming RSSI level you should use. I’m not sharing that because it’s trade secrets, all I’m saying is that if you use the defaults, you are in big trouble. One thing for certain is that you should use Radio Management for your code plugs and deployment because once you learn it, it’s far superior to the single file utilities, including being able to use the radio airwaves for OTAP. OTAP is great because you can accommodate complex code plugs with a lot less risk of screwing up. If you do screw up, running a reprogram doesn’t mean putting every radio on a USB wire. You can fix your mistakes in the background. It also helps when the customer wants changes.

Radio Management has a lot of issues, the biggest ones being that you can’t have multiple tenants in the same database and you can’t merge databases. These two issues make it so that you have lots of Radio Management PCs hanging around, one for each customer, plus your own. My experience with that team is they don’t care because most radio technicians don’t use it. Because of that a lot of the LCP systems are sub-par and don’t fully use all the features that are supported.