Comparison of digital PMR446 radios. dPMR446 and DMR Tier 1.

  Old radios:

Radio model	Digital mode	Approx. price	Waterproofing	Notes	Availability
Icom IC-F4029SDR	dPMR	-	None	First digital PMR446 radio.	Discontinued. Icom recommends IC-F29DR2 instead.
Icom IC-F29SDR	dPMR	-	IP67 (submersible)	Icom IC-F29DR with display.	Not officially discontinued but availability is poor
Icom IC-F29DR	dPMR	-	IP67 (submersible)		Discontinued - Replacement is Icom IC-F29DR2
Kenwood TK-3401D	dPMR	-	IP54 (splashproof) & IP55 (water jets)		Discontinued - Replacement is Kenwood TK-3701D
Kenwood TK-3601D	dPMR	-	IP67 (submersible)		Not officially discontinued but availability is poor
Motorola XT660d / XT665d	dPMR	-	IP55 (water jets)	Motorola's first and only dPMR446 radio. XT665d includes LPD channels (low power, not PMR446 and they have worse range so not much benefit of having these channels)	Discontinued - No replacement. Motorola only sells analogue PMR446 radios now.
Hytera PD355LF	DMR	-	IP54 (splashproof)		Discontinued
Hytera PD365LF	DMR	-	IP54 (splashproof)		Discontinued

Current radios:

Radio model	Digital mode	Approx. price	Waterproofing	Notes	Availability
Icom IC-F29DR2	dPMR	£174	IP67 (submersible)	Programming cable is about £50 and software (CS-F29DR2) is about £24.	Good availability
Kenwood TK-3701D	dPMR	£125	IP54 (splashproof) & IP55 (water jets)	Programming software is about £20 and cable is generic kenwood style so many can be found cheaply.	Good availability
Hytera BD305LF	DMR	£97	IP54 (splashproof)	Not so good build quality. Not recommended.	Good availability
Hytera BD505LF	DMR	£153	IP54 (splashproof)	Not so good build quality. Not recommended.	Good availability
Hytera PD505LF	DMR	£178	IP54 (splashproof)	Seems better build quality than Hytera BD series.	Good availability

My recommendations

For PMR446 use, dPMR is better for most users because it uses 6.25 kHz channels rather than 12.5 kHz which gives it slightly better range than DMR. DMR has to do some trickery to allow the same effective number of channels (32), whereas with dPMR there are 32 channels by default. For these reasons I recommend people pick dPMR radios over DMR when choosing digital PMR446 walkie talkies.

This leaves just the Icom IC-F29DR2 and the Kenwood TK-3701D. Both are good options. The Icom has better waterproofing (submersible) but is more expensive to buy. The programming software and cable are also much more expensive. The Kenwood is only splashproof and water jet proof but is cheaper, and the programming software and cable are also cheaper. It's not necessary for most users to reprogram the radio though, as it can be used out of the box.

The Kenwood is much better value for money so I would recommend most people choose this instead of the Icom unless you need a submersible radio. These radios will not be able to talk to each other out of the box due to being programmed with different CTCSS codes on the analogue channels, and different Common IDs on the digital channels, however they should be able to talk if reprogrammed using the programming software.

Compared to analogue (FM), which is what you get with cheaper PMR446 radios, the range of DMR should be about the same and dPMR should be slightly better.

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If you find any radios I've missed off this page, please leave a comment below and I'll update the page.  

Chinese dPMR radios comparison

Names	Type	Vocoder / Vocoders	Availability	3.125 kHz steps	Compatibility group	Notes
Puxing PX-508D, Puxing PX-558D, Radtel RT-14D, NRC DigiA	Handheld, no display or keypad	AMBE+2C	Poor	Yes	1
Zastone ZT-9908	Handheld, display and keypad	AMBE+2C	Poor		1
TYT DM-UVF10, Retevis RT2	Handheld, display and keypad	AMBE+2C	Poor		1
Puxing MD-500	Mobile	AMBE+2C	Poor
BFDX/Belfone BF-P108	Handheld, no display or keypad	RALCWI	Poor
BFDX/Belfone BF-P118, Luiton DG-1180	Handheld, display and keypad	RALCWI	Poor
Kirisun S780, Kirisun FP460	Handheld, display and keypad	ASELP	Poor	Yes		Poor range - bad receiver sensitivity.
Kydera DP-550S	Handheld, display and keypad	AMBE+2C, ASELP	Poor	No. Rounds to nearest so 446.103125 becomes 446.1		Terrible audio quality - very muffled sound. Does not work with other dPMR radios.
Recent RS208D	Handheld, no display or keypad		Good
Recent RS209D	Handheld, display and keypad		Good
Recent RS308D	Handheld, no display or keypad		Good
Recent RS309D	Handheld, display and keypad		Good
Sainsonic FM-416, HYND DP320	Handheld, no display or keypad	Probably ASELP	Poor

Vocoder
The vocoder is the part of the radio that converts your voice into very low bitrate digital data so it can be sent over the radio channel efficiently. Each vocoder will sound different because they make different sacrifices to compress the voice. I wrote a page about different dPMR vocoders here. Some radios are available with multiple vocoders so you have to make sure to get the right one. The only way to tell is usually by trying it, or sometimes the seller or manufacturer will be able to tell you. They often don't know much about their products though.

3.125 kHz steps
For a radio to work on dPMR446 channels it needs this. If not, it will be on the wrong frequency. The radios on this page are not legal to use on PMR446, however it is pretty common for people to program chinese radios to use PMR446 frequencies and as long as you fit in by using the right frequencies and bandwidth then it probably won't be noticed. Therefore, if you're planning to use one of these radios on PMR446 digital frequencies then you should get the one with 3.125 kHz steps.

Compatibility group
This is a term I just made up for this page. Radios in the same compatibility group should be able to talk to each other.
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If you're trying to buy any of these radios, aliexpress, eBay and alibaba are usually good places to search. eBay is usually the easiest as they will post from your country but only the most popular radios usually get listed there. Aliexpress is the next best but they post from China so it may take a long time to arrive.

Please leave a comment below if you have information missing from this page that I can add.

Quansheng UV-R50 programming software download

I found it very difficult to find this software online so thought I'd provide an easily searchable download link. For some reason it installs itself as TG-Currency03.exe. They probably just didn't bother to rename it from a default. So you'll need to look for that to open it once installed. I suggest you rename the folder during the installation to something sensible, so you know what it is later on.

If you're going to link to the download then please link to this page as I may change the download link if it breaks, and then your link would break too.

https://mega.nz/file/ZNwRkbzI#4srxAMaqACmBZFrLeoJFWEW2kzd_Eava56Rj23o3Pu4

The original link to the Quansheng website where this file is from, is below. I provided this just in case it actually stays up and doesn't break. It might be a good idea to try this link first because it may have a more up to date version of the software. 

http://www.qsfj.com/products/459

Tuning your hotspot (Pi-Star)

Tuning your hotspot is something you should do to get the lowest BER (Bit Error Rate) - that means to get the least errors in the digital data being sent by your radio. If you have a high BER then it causes your audio to sound bad to others or even to fail to decode if it's very badly tuned.

So to do this, first open up the dashboard of your hotspot. This can be accessed at pi-star/ usually. Then click on configuration near the top right of the page.

Next, in the same area click on Expert, then MMDVMHost. Scroll down on this page to the Modem section. You should see an RX offset field.

Now, set your radio to use a talkgroup/room/reflector where you won't be disturbing anyone by transmitting. I suggest using an echo test one. On the Brandmeister network this is done with a private call to 9990.

Open a new tab in your browser and navigate back to the dashboard. When you transmit, you should be able to see it under the Local RF Activity section. If you don't then it could mean that your frequency is off by such an extent that the hotspot isn't even detecting the transmission.

From here you can start tuning up and down on the RX offset frequency. I'd recommend going up or down in 100 Hz steps at first. Each time, save the new RX offset and transmit again for a few seconds. See if your transmission comes up under Local RF Activity. Look at the BER and write it down along with the RX offset. After some trial and error, you should find an offset that gives the lowest BER. If you are still increasing/decreasing the offset and the BER keeps going down, then keep going until the BER starts to increase again. At the minimum point, you've found the correct offset.

At this point you can either tune it further, by going up and down in smaller steps than 100 Hz, or you can just stick with the current offset. I'd recommend tuning it more if you have the time.
If you choose not to tune it further, then you're done!

dPMR vocoders

Kirisun S780. An example of a cheap Chinese
dPMR radio with the ASELP vocoder

There are a number of vocoders commonly used in dPMR. For those of you who are not familiar already with what a vocoder is, here is a brief explanation: A vocoder converts the voice signal into low bitrate digital data so it can be sent over a radio channel, and then converts it back to voice at the other end. This allows the voice to be sent in less bandwidth than if some other audio codec that is not optimised for voice (MP3 for example) was used, or even than analogue modulation. A vocoder is just an audio codec that was specifically designed to be optimised for voice, and usually will not accurately represent other sounds.

The dPMR standard has two bits allocated to denoting which vocoder is in use, allowing four choices. This is specified in the dPMR Mou tech.lib-Voc Bits-v1 document. The options are:

1. (00 in binary) Standard vocoder. AMBE+2.
This vocoder is very widely used in digital PMR/LMR products including in DMR, P25 Phase 2, and NXDN. It is a solid choice of vocoder, but far from the only choice. A sample of how this vocoder sounds can be heard at the start of this video. All Icom and Kenwood dPMR radios use this vocoder and are guaranteed to work together because they have been through interoperability testing.

2. (01) Vocoder to be selected by the Chinese DRA.

According to one commenter on this article, the DRA is a Chinese entity but seems not to have produced anything since 2010. I did some further research (originally for this article) and found out that DRA stands for Digital Radio Association. It seems they originally intended to create a dPMR based radio standard called NDR, using their own vocoder. dPMR radios with this vocoder could be sold as NDR radios, presumably to assure users that they would be compatible with each other.

I could not find any information about this vocoder online. I requested information from the dPMR association and they did not know what it was either. My guess is that the DRA and their NDR project got abandoned.

If any vocoder was selected, I believe it's highly likely that the ASELP vocoder would have been the one chosen. This is because it's a Chinese developed vocoder. See more information later in this article.

If you have any further information then please leave a comment below or contact me.

3. (10) RALCWI vocoder.
I have never seen a single dPMR radio using the RALCWI vocoder. I cannot even find any samples of what that vocoder sounds like online. I contacted the company that made this vocoder, asking if they had a sample, and if they would give me permission to post it. They said that they do have a sample but that "audio samples are only made available to known equipment manufacturers with a defined relevant project." My guess is that this vocoder must not sound very good, because other vocoder makers usually want to show off how great their product sounds.

4. (11) Manufacturer defined vocoder.
This is probably the second most used choice after number 1. Although the certified dPMR radios all use the standard vocoder, many Chinese manufacturers have been using the dPMR standard to create fairly cheap digital radios, however their radios have not been certified by the dPMR association so are not guaranteed to work with other dPMR radios. The manufacturer defined vocoder is not one specific vocoder. It can be any other vocoder that the manufacturer selects.

Other Vocoders

The vocoders that I have seen in use (with, I assume the manufacturer defined setting), are ASELP and AMBE+2C. More information is given below.

ASELP
A vocoder developed by the Chinese Tsinghua university. ASELP stands for Advanced Sinusoidal Excitation Linear Prediction and is not to be confused with ACELP, the vocoder used in TETRA. This vocoder was developed because of the desire for a vocoder with intellectual property rights that were owned by a Chinese organisation. There is not all that much information on this vocoder online in English, however you can read my attempted translation of the journal article describing this vocoder.

ASELP is commonly used in Chinese made dPMR radios and sounds fairly good. A sample of the vocoder as implemented in the Kirisun S780 can be seen in this video.

AMBE+2C
This vocoder caused a bit of confusion for dPMR enthusiasts because nobody seemed to know who it was by, if it was the same as AMBE+2, or if it was just a name made up by the Chinese manufacturers to trick people into buying their radios (which would not be surprising because Chinese radios are commonly listed online with exaggerated output power and specification claims).

I contacted DVSI, the company who made the AMBE+2 vocoder to ask them about AMBE+2C. They told me that it is their vocoder. It is made as an alternative to AMBE+2 but is not compatible with it. Although I was not given pricing information, I would guess that this vocoder is cheaper than AMBE+2 and that's why it is commonly used in Chinese made dPMR radios. It is available through a software licence.

My advice
If you're looking to buy dPMR radios then I recommend that you buy radios using the standard vocoder. These are sold by Icom and Kenwood, and they are all good quality radios. The dPMR radios sold by Chinese manufacturers are cheaper, but the quality is usually nowhere near as good, and you cannot rely on them to work with each other. Even within the same model of radio, the vocoder is sometimes changed, so if you need to buy a new radio later on then you might find that it won't be able to communicate with the older ones.

Jumbospot ethernet adapter

A cheap Chinese ethernet adapter

If you're thinking of getting an ethernet adapter for your jumbospot hotspot, watch out. The cheap Chinese ones on ebay (usually marked with the number 9700) have issues. See this link for full details. The short version is that they're only USB1 so are very slow, and they have a poor design that makes them perform sub-optimally.

They still work but it might not be as good as a properly made and supported ethernet adapter. The slow speed is generally not too much of a problem since hotspots don't need to transfer data at a high speed most of the time anyway. Digital voice is low bitrate, which means it only needs low speeds.


They should work out of the box, assuming you have a relatively up to date version of pi-star installed. I had to restart the hotspot to get it to work. I also noticed the dashboard loading much quicker than on Wi-Fi so even with the slow speed and poor design, it might be better to get one of these than relying on Wi-Fi.

Still, it would be better to buy one which is properly supported, like the 3 Port USB Hub w/ Ethernet - Micro USB (Pi Zero) sold by ModMyPi, Pimoroni and other retailers.

Update (19/04/2019): After about three months of use, I haven't had a single issue with this ethernet adapter. Although in theory they might not be completely optimal, I find that in practice they work perfectly adequately for hotspots. Hotspots generally operate at a low data rate, so the fact that this product only supports USB 1 isn't an issue for this use case. I recommend this product if you want to connect your hotspot by ethernet cable for more reliable connection to the internet.