Digital radios for longer distance

Good morning. My company is looking to buy some radios for our technicians on site and Ive been asked to source some. My radio background is sparse and limited to what I learned in the Marine Corps through normal interaction with tactical radios so Im coming to yall for help.

Our work site is about 4 miles in diameter and is fairly flat but we do have a lot of concrete and metallic structures around that we will need to have service in/on. The most important thing is quality voice communication but we would like to have some additional features like the ability for each tech to have his own channel and everyone have a “phonebook” so they can talk to individuals as well as broadcast to the whole group at once. Battery life needs to be in excess of 14 hours on a single charge. The units need to be atleast moderately water resistant (not gonna swim with them but they will probably be rained on and will surely get sweated on). We are trying to stay out of licensed bands but if thats what we have to do to get the range and reliability then so be it.

In my searches I found the Motorola DTR650 radio which seems to fit the bill in every category except range. Is there something similar to the DTR650 that will do 4-5 miles reliably?

As for cost, we would like to keep it under $400 per unit plus the cost of chargers and accessories.

Unfortunately, even digital can’t change the laws of physics. VHF and UHF radios are all line-of-sight, and four miles might be pushing it. As much as I love the DTR/DLR series, I don’t think you can expect that range from ANY radio.

That being said, it is my experience that the DTR radios have the best range of any business-class UHF or VHF radio. Plus, the one big advantage is that clarity is always 100%. The digital radios send out a handshake signal to be sure another radio is within range. If not, it won’t transmit. If there is another radio in range, you always transmit with 100% clarity.

Plus, as you say, the DTR can call up any individual radio from their user list, and the beauty of digital is that two employees can talk to each other on a “channel” (which isn’t really a ‘channel’ but more a frequency hopset) and others can talk on the same channel at the same time.

I would highly suggest you at least try a pair of DTR radios to see if the range is acceptable. The 900 MHz band is specifically designed for good penetration in urban environments and concrete buildings. But every environment is different. I have easily gotten a couple of miles range in a dense urban neighborhood, with lots of buildings, houses and trees between the two radios, but that may not be the same with yours. The only way is to try them out.

I would suggest using the longer 1/2 wave antenna (available for the DTR550 and DTR650) for maximum range. (The longer 1/2 wave antenna now comes stock on the latest versions of the 550 and 650.) If you have a local Motorola dealer, they may be able to lend you a pair to try out.

You don’t even need two people to test range. Leave one on at the farthest point and then travel the facility, pushing the PTT button. When it is out of range, it will squeal to warn you.

If you feel these may work - and they are certainly the only ones I can think of that might work, based on your needs - I would recommend you look at a fleet of 550 radios, and one 650 radio. This will save you a few dollars and you can use the one 650 for its management functions. The rest can all be the slightly less expensive 550.

The DTR410 has the same management functions as the 650, but is has the short stubby antenna. It will not have quite a long a range as the 550/650. (If you want to see the DTR410 is use, many Apple stores around here use them for their staff.)

Plus, there actually IS a repeater available for DTR radios. It only works on one channel and is not cheap (simply because it uses the internals of two DTR radios) but may work for you in a permanent facility location.

I have my own fleet of DTR radios, plus one DLR that our forum hosts at lent me to test. I absolutely love them. I have one DTR410 for management functions such as remote listening (in case of injured workers) and remote date/time synchronization, and the rest DTR550 and DLR1060 radios.

I should also point out that our forum hosts at are big Motorola dealers, and often have special deals on multi-radio purchases, usually with a free bulk charger. They are also very knowledgeable, and between calling them for advice and reading through this forum, all your questions should be answered.

The DTR and DLR radios are also licence-free in both the U.S. and up here in Canada, and there is no way to monitor a conversation with any consumer-level scanner.

Thanks for the input and suggestions man. I will go ahead and order 2 of the DTR650 and see how they work around site.

It is very unlikely that the DTR Radios will meet your needs.

You need to contact a frequency coordinator and get a license to set up your own repeater along with DMR Radios.

Alternatively, you could set up a Wifi network covering your campus and set everyone up with VOIP phones or a PTT app like Zello. Zello also offers a business class server that you could set-up and use at your business location.