A review of the new retevis rt51 -
an inexpensive PoC alternative.





The RETEVIS RT51 PoC Handheld radio is a Push-to-Talk (PTT) communications tool that uses existing AT&T and T-Mobile cellular infrastructure for voice signal propagation for business communications. The company presents it as an inexpensive business communications device and platform that allows for group and one-on-one PTT communications over great distances. The radio is listed for sale on their website for only $129.00 which is very inexpensive compared to existing similar radios on the market. You can see the listing and purchase here:

https://www.retevis.com/rt51-poc-handset-radio


Requirements to put the radio to work are:

1. a SIM card for at least 500MB data for each radio;

2. the ability to program each individual radio with the aid of a programming cable and a computer with proprietary programming software;

3. a web-based admin account to manage groups and users;

4. and access to the radio's data network and server which handles the connectivity and provides the web-based dispatch platform for managing all your business communications.


PTT radios and associated infrastructure for business and public services have been around for a long time. It has been pretty much dominated by Motorola, whose hardware, proprietary software and maintenance programs run in the very high dollar range which put it out of reach for many small businesses and organizations. With the development of cellular networks and VoIP technologies has come many new affordable alternatives for communications, many of which simply reside on your smartphone which does away with the radio factor. However, there still is a place for the simple, old-fashioned PTT radio.


Enter PoC radios. PoC stands for PTT over Cellular. There are a plethora of these devices and platforms showing up in the marketplace these days. They all require access to the internet, a data plan with a cell phone company and a communications server to connect to that provides the connectivity for the subscribed to services.


No matter which network or service you go with, there is some downside to VoIP communications. The first is the internet itself. If the internet goes down, so does your communications. Much like traditional RF systems, you must be within communication range of a receiving element in the system, either a repeater site or a cell tower. Typical repeater based systems have little latency or delay. However, voice quality and clarity degrade over distance and eventually become unreadable. On the other hand Digital VoIP communications are clear and readable no matter the distance until it pretty much just stops when you get out of range of the receiving site. One problem with VoIP is latency or the delay time from transmission to reception, which can be quite long and variable from network to network. The advantage of PoC is that the cell networks cover most of the US and are quite robust and reliable. Being as cellular is still RF, it is prone to the same issues as the older repeater based radio systems, valleys, buildings, and anything that obstructs line of sight access to the receiving sites and cell towers. However, most PoC radios these days provide Wifi connectivity to extend the network connection when indoors.





This is the first downside of the RT51 PoC Handset radio. It has no wifi capability. You are totally reliant on access to your provider's network. But, my testing of this radio proved that the external cell antenna on the radio does increase the range to access data connectivity. In places where I could not connect with my smartphone, I did connect with this radio. That did impress me.


The RT51 radio itself is a nice radio with a quality feel and function. It is actually manufactured by TYT, the maker of the now infamous MD-380, of which I own 2 for my amateur radio use for DMR. I love my 380s. They are very solid and reliable radios for the low price I had to pay. The RT51 is nearly identical to the MD380. That is what I love about this PoC radio.


As a small group of testers here in the US, we were able to figure out how to program our radios and get them connected to our various cell networks with some frustrations. As usual, Chinese documentation is poor and confusing. Largely because the Chinese have little to no experience with our networks here in the US. Once we got it figured out, we were able to talk back and forth over great distances easily with decent audio quality. The frustration began as we were introduced to the communication platform software. It is hard to understand and implement. Again, lack of clear documentation pretty much leaves you confused. I am pretty tech savvy and I found the process of programming my radio and setting up a group and users very frustrating and not intuitive at all. The dispatch software looks very pretty and usable with the embedded Google mapping and control interface that is used to control the conversations either one-on-one or group along with a large PTT button. I had success in communication with my radio from the PC and visa versa. But the GPS positioning and tracking did not work for me or my fellow tester. Plus he could hear me on it but I could not hear him.


By the way, the RT51 has built-in GPS that accesses satellites from an internal antenna. One of the menu functions show you your coordinates and how many satellites you have accessed. But I could not get the dispatch software to show me my location or the location of the other testers. Plus the default position of the map is China, not the US. The software also constantly shuts down and log you out when not in use for a period of time. That's not good for dispatchers who are waiting for communications from their teams. I'm not saying here that it won't work. We just didn't get to thoroughly test this platform with a large number of users to experiment with and not much cooperation in helping us build a larger testing group comprised of hams who are usually on the cutting edge of this kind of technology. We had pressure to get out our published reviews first before we could consider our other recommendations. All this to say that my review is based on very little experience with this platform. It may very well perform as it is advertised for you, if you are willing to go it alone without much documentation or support.


What is attractive about the RT51 and associated platform is the price. The radio is very inexpensive. You can get a data plan with T-Mobile for $10-$15 a month and the network fee is a mere $10 annually. I'd say that is pretty tough to beat when looking at other pricing structures for this kind of communications tool.


In all honesty now. Would I buy this radio for my business? Yes, if it worked right out of the box! But it doesn't. It appears that it is still in development. So, no. I wouldn't at this time. It looks promising. But there are far more intuitive and useful systems out there now that work well for business communications without a radio. Services such as Zello.com or OrionLabs.io. I am a fan of both of these very cool communications platforms and use them daily. However, if you are a communication tech or geek and want a radio to play with and see what you can do with it, have at it! It could be a lot of fun. I was given one as a tester that at the moment is nothing more than a paperweight. I will hold on to it for awhile and see what others can do with it in the ham community. The radio runs on Linux so if someone can gain access to it, who knows what could be done with it. I can't wait to see what the techs in the ham community will do with it.



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