Retevis RT84 Review

Retevis RT84 Average Price: £63.99

Review ᆞ Written by Sai (M7TEM)


Disclaimer of Transparency

This article is not sponsored in any way shape or form. I have not been paid to recommend anything over anything else. This article is entirely based on my own experiences and nothing further. I am not affiliated with, receiving kickbacks or rewards from any of the products or services that I am writing about in this article, nor am I using affiliate links to something like Amazon. If any article I write is ever sponsored, or not, in this case, I will disclaim it before the introduction as always.

This is part of my wider series on creating a budget shack. You can see the introduction article by clicking here.

Introduction

The Retevis RT84 is a semi-competent handheld radio. It is a good contender as a starter into the world of Digital Mobile Radio (DMR) that is both affordable and usable. A lot of digital radio at the moment is quite expensive and can demand quite a premium over the analogue radios with the Retevis RT84 being three times the price of the Baofeng UV-5R. The Retevis RT84 is one of the cheapest VHF/UHF DMR’s on the market right now. This makes it a good radio to look into, to test the waters as it were. To see if it is worth investing in a more expensive solution or not. 

I am not going to pretend that these radios are completely without fault, as unfortunately, there are quite a few problems and flaws. But at least it is a true Tier 2 DMR, that is compatible with repeaters, so you can rest assured that you’re not buying a Baofeng DM-5R. 

About the Retevis RT84 and Review

The Retevis RT84 is an aesthetically professional looking radio although it’s a little bit chunky. It is advertised with a frequency range of:

  • VHF: 136MHz – 174MHz
  • UHF: 400MHz – 480MHz

With a frequency stability of ±1.0ppm. My Retevis RT84 was advertised on eBay to have storage for about 120,000 contacts. But this conflicts with both the official Retevis website and CPS (Programming Software) where I’ve found that it’s actually around 10,000 contacts. It has channel memory storage of 3,000 channels. You can also label channels with up to 16 characters to allow for easier identification. I won’t put this down as a fault of the radio, but do keep this in mind when sellers tell you something like this.

These radios are a little bit more chunky and bigger than what I was used to with the Baofeng UV-5R (with a normal battery). Not including the antenna, the radios come in at 235mm by 62mm (or 56mm) by 36mm (Height, Width and Depth). With the radio, battery and antenna, it weighs around 570 grams. 

The Retevis RT84 is advertised as having an output of 1W (Low), 2.5 (Medium) and 5W (High) but like the Baofeng; there may be deviations to this. So it is a radio that is perfectly usable on foundation licence holders in the United Kingdom and is also well within the limit for the United States Technician Class. 

As standard, it features an SMA (Male) plug for antennas on the top of the device, which requires an SMA (Female) antenna or adapter. Generally, these radios will come with a stock antenna (Sometimes referred to as a rubber duck antenna) that work well enough, but you might want to certainly consider looking for better antennas for it.

The Retevis RT84 is not just a digital radio, it also receives and transmits analogue as well, which is clearly displayed on the screen which mode it’s in with an icon next to the channel reading “A” for Analogue and “D” for Digital. 

You can send SMS messages to people you’re in range of certainly, but there is no predictive texting even in its most rudimentary forms. 

It is a Tier 2 capable DMR radio with Direct Mode Operation (DMO) with a straight double time slot, also known as Dual Capacity Direct Mode (DCDM) allowing two groups of calls on the same frequency at the same time. The RT84 also uses the AMBE+2TM Vocoder, which sounds very crisp and clear, but obviously digital. 

You can also password protect it via power on, which you have to set up in the software so that when you power on the radio it will ask for a numerical password. I was able to set one that is eight characters long. This may help protect your radio if you lose it on the train for example, or if someone steals it.

The radio has the ability to encrypt as in you can select either basic privacy with four hexadecimal bytes or enhanced privacy with thirty-two hexadecimal bytes which are rather pointless for amateur use, and you can’t legally use this radio on 446MHz, so it’s an unusable feature as far as I am aware. Although again, this is not a fault of the radio.

I have found the sound quality to be quite reasonable. People come through nice, clear and crisp. The build quality isn’t all that bad in that it’s built quite solidly and has rubberised keys that light up. This isn’t too bad. 

Similarly priced radios on the market have GPS functionality, whereas the RT84 doesn’t. This is both a good and bad thing depending on what you want. Whilst some people may consider this to be negative, I actually consider this to be a big positive. For slightly ‘tin-foil hat’ wearing reasons. 

The volume knob on the radio has a slimmer profile than the Baofeng UV-5R, and it is also harder to turn. I consider this to be a good thing because it is harder to accidentally turn. The channel knob which is next to it is bigger, which takes most of the accidental turning, and this turns in steps rather than a free turn. This is a pretty good feature. 

Another good feature is that you can reprogram function keys to do a range of tasks which is fully customisable from the code plug software. This allows you to program the keys to suit your particular style.

The analogue mode works very well, I usually give off nice strong clear signals with great audio and I get back nice good audio too. The difference between this radio and the Baofeng UV-5R is night and day when it comes to actual audio. 

Programming the Retevis RT84

Programming any DMR is not going to be easy for first-time users, it is a bit of a steep learning curve, indeed. When you buy the radio, you will want to make sure you have a programming lead with it, as this stands it has the best chance of working with your radio. You cannot use CHIRP either. 

When I received mine, I found that the channel information stored some pretty random channels. I had to download a piece of software from the Retevis website called “CPS RT84”. There are a fair few videos on YouTube, guides and blogs on the internet that show you how to set up your code plug. Fortunately, RT84 is a lot easier to program because you can export channels and mess around with it in an Excel spreadsheet using copy and paste, then I just import it back into the software and upload to the radio. 

It isn’t as easy as CHIRP, and I’m not going to lie, it’s a steep learning curve for someone who’s never done it before, but if you get stuck and you go to a radio club, chances are someone there would be happy to help get you started. 

Going into this would probably be another article entirely. But suffice to say, it is a lot more involved than the Baofeng. There are plenty of video tutorials online, as well as other tutorials but if it is something that is wanted here (Let me know in the comments) then I shall make an article on that and link it here.

Encryption “Privacy”

Typically speaking in the United Kingdom, you’re not allowed to use encryption on amateur bands. Which to my knowledge includes basic and enhanced privacy on the DMR. As I explained in my PMR446 article, under 1.5.1.4 “Encryption”, there are two main types of encryption for this DMR. 

Basic Privacy
This can arguably be broken by brute force. I’ve heard that it’s a number between 0 and 254, but – from what I have experienced with a full DMR – it could also be a series of 4 characters called hexadecimal (0-9, A-F) which would be around 65,535 combinations.

Enhanced Privacy
This should be much harder to break. Because anyone trying to listen in would be required to know all 32 characters of the key in hexadecimal, in that order. But…

As I understand it: Both are pretty damn useless as they use an RC4 cipher which is broken anyway and has some serious weaknesses in it. 

To further point out how useless all of this is: I will mention an experiment that Vicky (M7TAL) and I had done. Even if you do use encryption for simplex then you should be aware of something that we discovered in our tests that don’t seem to be covered anywhere else online that we’ve seen so far. SMS messages sent via encrypted channels – are not encrypted at all. Indeed, it is sent out in pretty much clear text: 

Encrypted Channels still send texts in clear text
DSD+ Output

I was able to intercept this message via an SDR Dongle and DSD+. As you can see the message is not encrypted and can be read easily. This was sent on a channel that uses enhanced privacy. In a controlled test on an unspecified frequency with a dummy load, for experimental purposes. I don’t know if this is a common problem across all DMR or the Retevis branded radios, or just this model, but if this is unintentional then arguably this is a major security flaw. But then if it’s intentional and common across all DMRs then there is something that can be taken away from this: Text messages sent via encrypted channels are not encrypted. 

Don’t rely on the encryption to protect you completely from eavesdroppers under any circumstances stick to an end-to-end encryption messenger service. Although granted you’re probably not going to use encryption in the first place with this radio.  

Downsides and Things to Consider

On paper this radio should be incredible. Unfortunately, it has lots of little things wrong with it, and some pretty big things wrong with it too. The digital mode on the radio (You know, the whole point of it) is a bit hit and miss. In tests where I was outside and Vicky was inside, in direct line of sight, approximately 100 meters away. On the low, medium and high power settings, this radio will drop packets (Glitch the audio, or outright not play any audio) sometimes for absolutely no reason, even if the radio is still picking up the signal. Sometimes the audio will be quiet, and then the glitches will be extremely loud and high pitched.

Similarly priced radios on the market have built-in memory (Around 1GB) or a MicroSD card slot so you can record calls, whereas this doesn’t, at all. This is quite disappointing as it means no ability to record missed calls, voice messages and the like. 

The Retevis RT84 seems to be a clone of the Baofeng DM-1701. I am basing this assertion on what I found in the RT84 firmware which I obtained from the Retevis website. See picture below:

RT84 Firmware showing "DM1701"
If you’re going to clone…

The clip on the back is more sturdy than what I have experienced with Baofeng UV-5R. It’s not just going to fall to pieces on you; however, the clip’s grip is also much weaker. Which means it can and will drop from whatever is holstering it quite easily. The plastic used for the body of the radio is less resistant to drops than the Baofeng UV-5R, which is saying something. A modest drop from a height of a meter onto rocky concrete has put a noticeably deep groove into the corner of the radio. When the clip failed on my Baofeng, it dropped to the same texture pavement, and skidded onto the road with no damage whatsoever.

Replacement batteries are not readily available in this country (The United Kingdom) at the time of writing. So if your battery doesn’t hold as much charge as it once did, or you’d like some spares and backups then you’re out of luck, or you’re going to have to manually replace the cell which is dangerous. This is a serious problem; especially coupled with the next problem…

… The battery life on this radio sucks. Yeah. I’m not even joking.

Whoever said that battery life on a digital radio lasts longer than an analogue radio has never used my RT84. Typically speaking I can get around two, maybe three days standby time with the Baofeng UV-5R. With this radio I barely get one. If I am using the RT84 I can absolutely forget being able to use it for four hours. On low power (1W). If you have better performance on this, then that’s awesome. We’ve tried three different batteries here and the story is the same. If I was to guess as to the culprit, it’d be either the power used by the central processing unit (CPU). Or perhaps something else going on in the device other than running the transceiver. Both Digital and Analogue are power-hungry – even on low.

SMS sounds like a fantastic idea, but its implementation is stuck in the mid-to-late 90s. It is a bit of a pain in the backside to send SMS. With absolutely no guarantees that the other person will even get the message. For example, just to type “Hello” to someone you have to press the following buttons in the composer.

“4, 4, 4, 4, 4, 4, Down Key, 3, 3, Down Key, 5, 5, 5, Down Key, 5, 5, 5, Down Key, 6, 6” and then “6” again. 

The software/firmware leaves a lot to be desired: Every now and then the radio will crash and will need restarting. Every now and then the radio will display a blank screen which requires restarting. Or perhaps the screen entities; such as the blue bars around “Menu” and the mute icon will completely disappear. Or it’ll glitch out leaving a white bar, or a glitchy bar at the bottom of the screen.

Quality Control is abysmal. A good example of where something is off with the RT84 is just by looking at the screen. The LCD is tilted a good few degrees clockwise. It might not sound like much, but believe me – you can notice it when you’re using it. It even shows up pretty well in the picture to the right there. 

The LCD Screen on the Retevis RT84
Although it is a nice clear display, which is nice.

For some reason, digital transmissions on this affect all the audio equipment in my shack, with this radio. My microphone picks it up as audio, and Victoria’s (M7TAL) DAC picks it up and goes absolutely haywire; jamming the volume all the way up and amplifying it right into her ears through her headphones. You can hear what I am talking about here:

Recorded a sound from my mic whilst transmitting on digital. This is what the microphone picked up.

Seeing as in some mild sense that both Vicky and I are audiophiles, this is a major thumbs down. Other radios (and more powerful radios) do not cause this kind of interference. 

The power-on password can be easily defeated with the use of a programming cable. Although you can put a password on when reading from the radio, which I would recommend putting in a “PC Programming Password”. Just don’t lose that password.

This was my first impression of the radio when I turned it on for the first time:

RT84 Glitched Screen
Whoops.

There is absolutely no variable frequency oscillator (VFO) functionality on this radio that I could find. Granted it’s not literally VFO and that’s not what I am expecting. Most of these radios are more akin to software-defined radios (SDRs). But the one thing that I really like about the Baofeng UV-5R is going into “Frequency Mode” and browsing the spectrum. You can’t do this on the RT84 and I don’t really see any good reason why this feature isn’t present. 

Conclusion

I don’t want to be ‘Mister Negative’. I hate being ‘That Guy’. But at the price that is being asked for this radio I would have expected better. Overall I was extremely disappointed with this radio. Look; I know that DMR demands a premium price point when it comes to radios. But at three times the price of the average Baofeng UV-5R? I expected to see a little bit more for my £60, as my expectations on a £20 analogue radio had been set. As an analogue radio, it works better than digital and therein lies the problem. When your Digital/DMR radio is better at analogue than it is at digital, something, somewhere along the line has gone rather horribly awry. It makes you start to question your life choices. 

Does it work on digital? Absolutely. Most of the time, anyway.

I cannot hand on heart recommend this radio to anyone, without at least making them aware of these flaws. If I had known about these problems before I purchased the radio I certainly would have gone for something else. If you can’t afford anything better or you think you can put up with the downsides then by all means, more power to you. However, I recommend shopping around for a bit and looking at other reviews, personally. If you already have an RT84 on the way then at least you can gauge whether or not DMR is for you or not. Bearing the limitations and curbing the expectations, of course. You wouldn’t want to sink a lot of money in a high-end one, only to find out that you don’t like DMR at all. 

The radio has at least done this for me. I am interested in DMR, and I want to dive deeper into DMR. As soon as I can move away from this radio, I most certainly will. I’d be curious to know what problems, if any, Retevis can fix with firmware updates. But in the state that it’s in right now… Yeah-no. I do not recommend this radio at all.

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