Motorola DTR550 detailed review

I review the Motorola frequency-hopping spread-spectrum (FHSS) licence-free DTR410, DTR550, and DTR650 radios.

Transmissions with the DTR radios are very clear and they have about the best range possible with any VHF/UHF portable radio. (Like any VHF or UHF portable, they are basically line-of-sight, so distance evaluations are always subjective.)

To test the range, I turned one on, left it in the kitchen and then walked down the street with a second one in my pocket while I went to the nearest pub for a cold draft. (It has been almost 30 degrees C this past week!) When both are on, pushing the PTT causes a short ‘handshake’ to take place to make sure at least one other unit is in range. This is indicated by the “Nextel-like” tone. Once the tone ends about 1/2 second later, you can start talking. If the other radio is not in range, you will instead hear a loud beep. You don’t even need a second person to do range tests.

Basically, I was able to walk about 1 to 2 kilometres through this dense residential area. The signal had to penetrate all the large, wood-frame homes, mature elm trees and a large school, all within the line of sight. When I made it inside the pub, I lost the signal but walking out the front door regained it again. (Don’t forget the other radio was INSIDE my house.)

This was quite impressive, and exceeded any FRS/GMRS or business radio I have used in the same area by at least 1 city block.

The DTR-series radios are digital radios, which means there is about a 1/2 second delay in the transmission. It also means that there is no fuzzy transmission from the far edge of their working range; they are either 100% clear or they don’t transmit at all. When tested side-by-side with one of the best of the bubble-pack GMRS radios, the DTRs were much clearer.

The clarity is the same or better than any high-end business radio, and the mil-spec build quality and weatherproof design makes them expensive but easily worth it in my opinion if you are seeking this level of quality, reliability and readability.

Because they are a FHSS radio, there is no licencing required in either Canada or the U.S. They transmit on the 900 MHz band, which is shared with millions of cordless phones and other electronic devices but the Motorola only stays on one frequency for 90 milliseconds, and would not cause noticeable interference with anything else. One cannot eavesdrop on a conversation with consumer-level scanners either.

All Motorola accessories designed for the radios fit well. It is important to note that not all third-party accessories fit properly. There is very little clearance in the socket for mic/headset accessories, and one MUST use the two-prong Motorola plug that fits these tight sockets. There are two versions of two-prong plugs designed for Motorolas, so I would highly suggest that before you use a non-Motorola product, you test them first.

The reason is actually quite simple. The one version has SLIGHTLY shorter prongs than the other style. One CAN make them fit by some judicious trimming under the prongs with a razor knife, but it is better to get the proper plug on your accessories in the first place.

Accessories such as speaker mics and two-wire surveillance kits work fine and the clarity is great. It is important to note that one can adjust both the volume and microphone sensitivity of the internal mic and speaker AND external accessories attached to the radio separately.

If you are using them in windy conditions, it is a good idea to lower the mic sensitivity or you will pick up wind noise that sounds much like static, but isn’t. (This is easy to change … once I found out what setting to use. More on that in a moment.)

So, everything is great about these radios? Well … not quite.

At the time of this review, the support from Motorola and the user manuals needed work. The manuals have contradictory and missing information and it took DAYS of working with the radios in one hand and the manuals in the other to try to figure out how to program them.

Here are some examples. On page 2-17, it explains how one can change the volume of the ringer, speaker, keypad, alarm and talk-permit tone (“Nextel-like” beep to confirm another radio is in range.) The only problem is, there is no ability to adjust the volume of the talk confirmation tone on that generation of DTR410, 550 or 650. The talk-permit tone simply gets louder as the speaker volume is turned up, and contrary to the user manual, there is no way to turn it down independent of the speaker. EDIT: This was added to the generation 3 version of the DTR radio firmware. See subsequent post. It appears Motorola printed a feature in the manuals long before they were actually available on the radios.)

On page 2-18, it also explains how to adjust the microphone sensitivity to the ambient noise of the environment. In the first paragraph, it states that a LOW setting means the setting for low ambient noise areas and increases the sensitivity of the microphone to high for good clarity of sound. (On low, even a soft whisper comes across clear and understandable.)

In the very next paragraph, it contradicts itself, and says that setting the ambient noise setting to low is designed for HIGH ambient noise environments and DECREASES the sensitivity of the microphone. When I tested it in very windy conditions, and the first paragraph is correct; the second paragraph is wrong. If you are using them in a high noise environment, set the ambient noise setting to HIGH, and if the ambient noise is low, set it to LOW. When set to LOW, it increases the mic sensitivity so you can clearly hear a whisper. When set to HIGH, it decreases mic sensitivity so high ambient noises like wind and running machinery do not overwhelm the signal.

Motorola has free programming software for all three models, although for many years, the software was only available for the 410. It now works on all three: 410, 550, and 650. To program them by computer, you need a special programming cable that plugs into a serial port on your Windows computer. For computers that do not have a serial port, use a serial-to-USB adapter. The most problem-free adapters use what’s called an FTDI chip.)

One can program the radios manually without the programming software of course, but this takes a very careful reading of the manual and a long and laborious process. On my private “net” of DTR radios, I wanted them to have unique names so I purchased the mini-keypad to help program them with unique names. I didn’t want the screen to read “public group1” and the user to be listed on my contact list as “12345678910” so I used the mini-keypad to change the names and add some more text messages.

With the mini-keypad, I erased the default messages, added some new ones, changed the name of each radio into something that actually made sense, moved from the default channel 1 into a less-likely to be used channel and then added each of the other radios as a private group. Once you do all this programming on one, you then do it for all the rest. Once that is done, you then have to go into the programming menu (which takes holding down the “home” button while pushing the PTT 3 times, then pressing right bar button, down button, left bar button, holding down the “home” button and pressing the PTT 3 times again, to get into the programming menu) on one radio, selecting the name of the other radio and then when programming the ID, you select “read” and press the “home” button of the other radio 3 times and then the PTT, and this adds the other radio to the first one.

You then do this in turn with each radio you have so that every radio will recognize every other radio. Simple. It actually works great, but you can begin to see why this takes hours to do all this. (And why I spent so much time down the street in the pub drinking cold beer!)

That being said, one can simply unpack them, turn them on and use them without any fancy programming needed. They default to channel 1 and unit ID 1, and Motorola DTR radio will work with any other DTR radio right out of the box.

Currently, I am now working with the various “public group” and “private group” options, plus trying to calculate how many possible channel combinations there are. (The DTR radios don’t really use fixed “channels,” they are Motorola’s proprietary channel hopping algorithm.) There are 10 “channels” one can set their radio on, and 100 possible unit ID numbers. Each radio must be set to the same channel plus the same unit ID number to be heard by each other, but each unit ID number can be used only once. By my math, this means there are 955 unique combinations one can use.

So the bottom line is that they are great radios, but with a complicated user interface and a confusing manual. But once programmed, the battery life (lithium batteries) is incredible, the range is about the best you can get in any UHF radio and the clarity of the transmissions is as good as any other business radio on the market. If you listen to the comparison sound files on the website, you may notice a slight “digital” robotic sound to some of the words, but in actual use, I don’t notice anything like that. Every word is clear, and there are times I wish my cell phone had this same readability.


What about downsides? Well, at the time of this review, the DTR series was relatively new and even Motorola support didn’t know much about them.

But as of 2012, the programming software is now free and available for all DTR models. The manual is still confusing and it can take a long time to figure out the various capabilities of this radio, and to set up public and private groups. But once you get everything figured out and programmed, the advantage of the digital radio is that you can call any individual radio or even a smaller private group of individual radios, and still leave the “channel” free for conversation among all the other radios in your public group.

It took two days of working with these radios and programming them manually but I now have my own private fleet of radios, all programmed to a unique channel and ID number. Each radio now has its own unique identifier, such as “Chickenhawk One” and “Chickenhawk Two” etc. instead of the factory identifier such as “123456789.” They all broadcast on a public group that also has a unique name (“Chickenhawk’s Group”). If I ever get more radios in my fleet and need to create subsets of the main group, I could set up private groups, so I can call all the radios in the main group, all radios in any one of the subset private groups or call any radio individually.

I have found that users do not expect a time delay and need some basic training, or you will lose the first half-second of their conversation. They also hear the talk permit tone and back off the PTT, so you lose ALL the conversation. All it takes is to instruct users to push AND HOLD the PTT, and wait until they hear the talk permit tone and then they can start talking. They should also get into the habit of holding down the PTT for another half second after they finish talking so they don’t cut themselves off. The PTT is quite sensetive and there is no delay when you release the button, so users who don’t understand the digital nature of these radios may cut off parts of their conversation until they get used to them.

Like any other digital radio, once they are out of range, they are out of range. There will be no transmission at all if the radios cannot send a clear signal. This means that when you are on the outer edge of the transmission range, you will NOT receive a fuzzy, almost unreadable signal. They either transmit with 100% clarity or they don’t transmit at all.

But the bottom line is that they are very good radios. If one is looking for an industrial-class radio that operates on an unlicenced spectrum and wants better quality than bubble-pack GMRS radios, they should seriously consider these.

Good review… I made it “sticky”. It wil be there on top.

Sorry if this sounds silly but these would be better overall performers than the TriStar TSX300R would they?

I can’t speak to that issue because I don’t own the TriSquare radios.

TriSquare advertises their range as at least as good as any UHF/FRS/GMRS radio, and that make perfect sense. The Motorola DTR radios don’t have an advertised range but advertise they should work throughout 35 floors of a building. (UHF is better for penetrating glass and concrete of urban areas, while VHF is better able to punch through vegetation of rural areas.)

They are also totally different radios. The TriSquare radios are consumer-grade radios, with their own unique frequency-hopping algorithm.

The Motorola DTR radios are business-class radios, made to industrial-grade (and mil-spec) standards. They use their own frequency-hopping algorithm which is much faster than the TriSquares. (At 90 milliseconds frequency hopping, there has been no documented case of a consumer-level scanner being able to eavesdrop on a DTR conversation.)

They are also six times the price.

Now whether these industrial-grade radios are worth six times the price to YOU is entirely your decision.

I think it is great that there is an option for a high-end business class radio on the unlicenced spectrum, and they were certainly worth six times the price for me. I use business-class two way radios every day. I wanted some personal radios that I could legally use for business use and that had industrial-grade construction. I chose these ones.

Yes, there will always be a market for people who want the best radio they can afford at the lowest price, but I wanted the best radio, period.

Thanks for the insight, yes for my “amateur” use I don’t need that type of equipment, but it’s always fascinating to read discover new technologies thanks to in depth reviews and posts in forums :wink:

Still using my FRS Motorolas, might go with the Cobra CXR925 for the recording mode and at some point try the TriSquare (thanks for gently pointing out my mistake). Not directly related to the topic at hand but when I looked up the FCC ID of my old and more or less defunct Uniden radios from 2001 I noticed that TriSquare was their maker, not entirely to the radio business as I think I read somewhere :wink:

For me, readability of the transmission was my number one priority. My Motorola Talkabout T6220 radios have always been my ultimate FRS radio for range and readability and they may be ten years old, but they still work fine, but I wanted the larger speakers, industrial-grade components, water resistant design and the high audio output power of these mil-spec DTR radios.

I would like to detail the differences between the various models and generations of the Motorola DTR410, the DTR550 and the DTR650 models.

While the DTR410 is considered to be more of the “consumer” version of the DTR series, ALL Motorola DTR series radios are expensive, industrial-grade mil-spec business radios.

The DTR410, DTR550 and DTR650 are basically the same radio. Other than the color of the faceplate, the differences between the models are in the firmware programming and the antenna.

First generation models of all three radios came with moulded-in fixed antennas about 1" in length.

Second generation models kept the fixed antenna on the DTR410, while the DTR550 and DTR650 both received a removable 3" rubber ducky antenna. The DTR650 has a larger capacity battery, a faster 1-hour charger and management functions in its firmware for remote monitoring, remote disabling and remote time setting. The gen 2 firmware also added the same management functions of the DTR650 to the DTR410.

Third generation models added a longer 7" half-wave antenna to the DTR550 and DTR650. The DTR550 got the 1-hour charger and gen 3 firmware added more private and public groups plus the ability to control the volume of the talk-permit tone. (The new 7" half-wave antenna can also be installed on any older DTR550 or DTR650. It is Motorola stock number 8505241U04.)

Motorola did running updates to all models so there may be no firm dates for changes and there will be some overlap between generation two and generation three models. First generation models can be recognized by the fixed antenna on all three; second generation models have 3" antennas on the 550 and 650, and third generation models have 7" antennas on the 550 and 650.

To test the various antennas, I did some informal range tests. I tested a 410 with the fixed stub antenna, a 550 with the 3" rubber ducky antenna, a 550 with a 7" half-wave antenna and a 650 with the 7" antenna, all at the same time and in the same conditions. I did get a LOT of strange looks. (Try walking through YOUR neighborhood with four radios dangling from your belt in the pouring rain.) The receiving radio was a DTR550 with a 7" antenna, sitting upright on the seat of my car, inside a wood-frame garage.

The differences were noticeable but less than I would have predicted. The 7" antenna radios had about a block longer range than the 3" antenna radio, and the 410 with the stubby antenna had about maybe 1/2 block less range than the 3" ducky antenna. I was walking through a very dense urban area with a lot of old houses and streets lined with mature elms and I expected more difference in range than than I actually observed.

Differences in firmware were more significant. The second generation version of the 410 has updated firmware that gives it nearly the same ability as the 650 radio. For example, one feature that the 410 has that the 550 doesn’t have is the 650’s “manager mode.” When this is turned on, a 410 can remotely send a time synchronization signal or remotely disable any 410, 550 or 650 radio, provided the other unit is programmed in to the 410’s contact list.

Another interesting new feature is the remote monitoring, where a 410 or 650 can send a signal to any 410, 550 or 650 on its contact list to open its mic and start transmitting. This would be a great way for a manager to be able to monitor if a distant worker is injured and cannot call for help.

So the bottom line remains that these are expensive but high-quality radios that should last for many years. They don’t need any programming to get them to work right out of the box, but if you spend some time with the user manual, you can program them directly through the keyboard for most simple tasks such as changing the factory default channel settings and adjusting the user interface settings.

If you buy the optional mini-keyboard, you can even do additional programming such as using unique names for each radio plus your private and public groups, and programming in some additional text messages. (Yes, you can actually text message the other radios, using built-in text messages - but this would be so slow and laborious that i doubt anyone would attempt this.)

With the new Customer Programming Software (CPS) now available free from Motorola, there is less need for the keyboard accessory and is now out of production as of 2014.

By the way, digital radios have about a one second delay in the transmission, so if you ever want to freak out digital radios and open a hole in the time/space continuum, have one DTR radio close to you while you talk very briefly into another one and hold down the PTT button.

Because of the delay in the digital transmission, when I say “walkie check” into the first radio, the second one transmits the phrase about a second later; the first radio hears the second radio and retransmits the phrase and so on and so on.

I must have heard my voice echoing back and forth about a hundred times.

Very freaky! :):):slight_smile:

(Yeah, I know … I need to get out more.)

hehe…a bit like looking from a mirror in a mirror!

Sadly, TriSquare is now going out of business, leaving the Motorola DTR as the only FHSS digital radio on the market that transmits on the unlicenced 900 mHz band.

The Motorolas are high quality radios, with about the best range of any UHF portable radio on the market. They are also VERY secure in that no one has been able to monitor an actual conversation on one, and there are almost 1000 unique “channels” that one can use, so the possibility of someone else on your channel is virtually zero.

The trend today is to digital radios, and there are more and more businesses and public service organizations transitioning to digital. This is why I am updating this review and pointing out that one must understand the advantages and limitations of digital.

Advantages? They are very clear. They signal is the same, no matter how far away they are from each other.

Disadvantages? Once they are out of range, they are out of range. The sound clarity is either 100% or they don’t communicate at all. (They send out a short ‘handshake’ signal to be sure another radio is in range before it opens the ‘channel.’)

There is also a short delay in the transmission.

Early digital public service radios suffered from an effect where the digital signal would become overwhelmed by high noises such as near running loud machinery. (Several fire departments had to transition back to analog for a few years when their digital radios wouldn’t work consistently, near a running pumper truck.)

The DTR radios never suffered this effect.

One interesting point is that we can thank a Hollywood actress for much of this technology. Frequency-hopping, spread-spectrum (FHSS) radio transmissions were first patented over 70 years ago by a very clever Hollywood actress named Hedy Lamarr. (She actually had to patent it with her composer because in those days, women couldn’t hold sole patents!)

One wonders if the Paris Hiltons or Lindsay Lohans of the modern world would ever contribute anything similarly substantial beyond mugshots and paparazzi photos!

Well, maybe in the future, we will see similar technology at a cheap price, similar to the TriSquares. We can hope anyway.

Are there any other manufacturers making comparable radios to the Motorola of the same quality and feature set? Also are there any other good radios that have come out lately? Great review and sorry my question is slightl;y off the main topic of the DTR550 but I’m curious about your opinion concerning other manufacturers.

Thank you in advance.

We purchased two DTR650’s… and you’re right. What a pain to program.

I actually wonder if I should have purchased a non-digital radio.

We also purchased some earpieces with boom mic, but can’t get them to work.

Have to say, standard radios are usually so much easier.

Ok… got them talking on a private “channel”. I didn’t know the CPS software uses one profile for multiple radios… (Duh :slight_smile: ).

The earpiece is a model 56518… which is supposed to be compatible with this radio. When I plug it in, I can hear, but transmitting, is what I can’t figure out.

Keep at it. It seems overwhelming at first, but they are great radios.

As to that headset, it should work fine. Make sure the plugs are inserted fully, and keep in mind that there is no push-to-talk switch on them, so to transmit, you simply press the PTT on the radio itself.


With the headsets, the radio PTT just beeps when I press it without actually transmitting. I noticed a setting in the CPS that may have something to do with it. Disable PTT when accessories are plugged in or something.

I have to check it and see… because I’m not sure if it is referring to the bottom connector, or the audio connector.

I’m not a lawyer and I do not specialize in communications law.

But as an amateur, I can tell you that although you call it the unlicensed band - everything is licensed with the exception of CB radio and FRS radio and maybe MURS.

A number of years ago, Motorola came out with a FRS / GMRS that used a simple $15 encryption board and sold a number of units.
They received a rather large fine and was forced to discontinue their manufacture and to recall as many unsold units as possible.

They also came out with another unit that did Split - Spread Spectrum - and the same thing happened, they were fined and forced not to sell them anymore.

Amateur radio - Part 97 says nothing is to be encrypted - everything has to be in plain English, and if your license is for the USA, you can operate in any language, but when you identify your station - it has to be in plain English - not the language you are talking with.

The radio you are talking about is not consumer grade radios and are not designed or intended for use by John Q. Public.
Technicially, they shouldn’t even be sold to anyone without a license - such as a LMRS technician…

As far as it working through steel and concrete - I doubt it.
Someone here is smoking something.

Most modern building materials are opaque to most higher frequency radio signals.

This is the reason why you lost reception when you went into a building.
That was just two walls - the wall of the building you walked into and the building your other unit was in.

Working inside of a building would require the building not to have low E glass and for the signal to travel out of the building through a window, hit something, bounce back in through another window.

It won’t penetrate feet of concrete.

These are not Amateur radios and do not fall under Part 97. They fall under Part 15.

The Motorola DTR radios operate on 900 MHz ISM frequencies using FHSS at 1 watt, so no license is required from the FCC. Frequency Hopping Spread Spectrum technology is not encryption, but because of the number of possible combinations available using the FHSS algorithm (TriSquare claimed up to ten billion possible channels on their radios) the chances of someone else listening in on all or part of a particular transmission is very low, thus making such transmissions more private.

TriSquare used eXRS, which is proprietary, but the basic concept is the same.

Although Motorola primarily markets their DTR radios for business applications, technically they can be used by anyone. No FCC license is required to operate these radios.

Rick is, of course, correct. There is no licence required to operate the DTR radios in either Canada or the United States.

They are also not encrypted radios, nor do I recall anyone suggesting they were.

The DTR radios can be monitored with no problem by anyone within range, equipped with another DTR radio, tuned to the same channel and same unit ID. They are not encrypted in any way.

Because they hop frequencies so fast, they would not cause any interference with the multitude of other devices on the 900 MHz band. It is technically possible for a high-end multi-band scanner to keep up with the hopping algorithm, but in actual practice there has been no documented instance of any consumer-level scanner being able to monitor any kind of conversation. (They are also a digital transmission, unlike the TriSquare that used analog transmissions.)

Perhaps this is why Tower Tech mistakenly thought they were encrypted. They are not. They are very secure, but they are not encrypted. (And I do know the difference - which would be quite clear if you knew what I did for a living.)

As for working better through glass and concrete versus trees and vegetation, this is simply a function of UHF versus VHF. Motorola rates the DTR radios to work through 30 floors, and last time I checked, most multi-story buildings are made from a high portion of concrete. Whether the signal actually penetrates the concrete or goes out a window, bounces around somewhere and comes back in another window, doesn’t matter to me. They work and I am sure they would probably work through pretty darn close to 30 floors if I ever had the opportunity to try them. And I don’t even smoke.

Motorola, the FCC and Industry Canada are all very clear on the fact that the DTR radios don’t require a licence. I know this may be hard for some amateur radio operators to accept, but it is true.