DMR: a miracle mode?

There are miracle antennas (read my lips!) and now there are miracle modes.

The reach of a DMR radio extends 10 x the distance of FM or D-star at the same Power level.”

DMR Range

Maybe I should do that IQ test; it could be that I lack sufficient intelligence to go on with this hobby.

(Seen at D-Star Radio Club International)

Review Connect Systems CS700 DMR Handheld

Let me start with a confession: personally I don’t care much about digital modes. That doesn’t mean that I don’t keep track of the latest technologies, and (hopefully) this short review is proof of that.

DMR-logoI’m not going to explain in detail what DMR (Digital Mobile Radio) is, as there are many sources on the Internet that will do a much better job than I could.

For your convenience I uploaded a DMR primer, the link can be found at the end of this article. What I would like to do here is give you a basic idea of what you can expect, and – just as important – what not.

What you can expect

  1. Talk around the world by using repeaters. The functionality isn’t much different from D-Star.
  2. Optimal use of frequency space (time slots). DMR uses 2 time slots, which makes it possible to have one frequency harbor two QSO’s at the same time without interference.
  3. Extensive encryption options to prevent eavesdropping (illegal for ham use). Unless you know one key (basic privacy) or two keys (extended privacy) other people can’t listen in.
  4. On-screen call sign recognition. In order for this to work you need to update the subscriber ID list regularly. This will also open up the option to use ‘call routing’ (calling a specific station regardless of his/her location in the world). You can get your own subscriber ID here.
  5. Sending and receiving text messages. Think of it as SMS on a cell phone. You can compose messages on the fly, or program a number of preset messages.

What you shouldn’t expect

  1. A technology tailored to ham radio use. It’s not. DMR was conceived with commercial purposes in mind. You won’t find any dual-band radios, for example. If you want to have a mature, ham oriented digital system, go for D-Star instead.
  2. Great audio quality. Seven out of ten times I wasn’t able to recognize familiar voices, not even from people I talk to on a daily basis. Most people sounded like they just had a root canal, with a truckload of anesthetics preventing them from forming words properly. It’s a bit less poor than D-Star, but opinions vary wildly.
  3. 100% compatibility between various brands. There are some minor differences between Vertex/Motorola, Hytera and this CS700, but making QSO’s will always work.
  4. Plug & Play out of the box experience. If you open the box the radio is nothing more than a clumsy paperweight. You need to program it.
  5. Using these things to the max without some basic computer knowledge. If you hate computers, DMR is not for you. The number of screens to-be-filled-in in order to make a so-called ‘code plug’ will initially make your head spin. Fortunately you can almost always download a ready-to-use code plug made by someone else.

CS700Making a splash
If Connect Systems did one thing, it’s making a splash. At €249 (Europe) the CS700 is by far the most affordable DMR Tier 2 transceiver available. Please note that the European price includes all taxes, transport from the USA to Europe, parcel insurance and the seller’s margin, while USA prices (as low as $180) might not.

Contrary to earlier reports this radio is designed and manufactured in China, but it doesn’t breathe the poor workmanship you sometimes see in the world of Baofengs. This is a high quality, sturdy radio.

In the box
– radio
– battery
– charger
– power supply
– manual

Optional: programming cable. This might look silly because the radio is worthless without one, but it does prevent you from paying for cables over and over again if you buy more than one radio. Drivers, programming manuals and programming software can be downloaded for free at Connect Systems. New firmware releases will be posted there also.

First impressions
I only programmed 2 zones of 16 channels each, because that was all I needed for this review. The maximum number of zones is 250, but I doubt that you will ever need that many channels and zones.

CS700 Programming SoftwareIt was surprising to get this radio up and running almost instantly, and the first QSO was made within minutes. The audio quality is poor when compared to FM analog, sure, but it is totally noise-free. This can also lead to mistakes once in a while, because you can’t always hear when it’s your turn to talk. Setting the ‘Talk Permit Tone’ to ON will prevent confusion.

RX quality
Excellent. Better filters, good sensitivity, great selectivity. I can even connect the CS700 to an outdoor antenna, something I can’t do with a Baofeng. Even my Kenwood TMV-71 can’t handle the RF pollution here.

TX quality
The first thing other stations mentioned was that my TX audio level was low when compared to most other stations. At first we thought this might be a CS700 problem, but that proved not to be true. Actually, the CS700 did it right, and other radios did it ‘wrong’.

As it turned out most users of Hytera radios had their digital microphone gain set to 18 or even 20, while 10 is the correct (factory) setting. The excessive gain setting not only resulted in huge audio level differences between stations, but made setting the RX volume on the CS700 almost impossible. I had to turn the volume just a fraction above zero if I wanted to listen to Hytera users without experiencing how fast a loudspeaker can self destruct.

The latest Hytera code plugs made by PA2JM and PA3EHA have the gain set at 10, which results in all radios being equal. The same problem and solution is probably true for Vertex/Motorola radios as well.

Battery life
I’m not really impressed by the battery life. I could get about 8 hours of life out of it, with RX  95% of the time and TX 5% of the time. I did use the maximum power output, which is 4 Watts. Buying a spare battery is a necessity.

Measurements
Power output is slightly higher than the the factory promises: 4.2 Watts (high), and 1.1 Watts (Low).
Harmonic suppression is excellent: -62 dBm for the second harmonics, third harmonics was undetectable.

cs700Bugs
Most bugs are related to the programming software. You can keep track of bugs, fixes and workarounds in the CSI DMR Yahoo group. Only one bug is somewhat annoying: the slow scan speed for digital channels.

Conclusion
This is a very nice, well designed and affordable DMR radio. Battery life could be better, scanning is slow, the radio can’t do roaming, but other than that there isn’t much else to complain about.

Yet I wouldn’t immediately recommend a CS700 as a primary DMR radio, unless you have access to a local repeater. A mobile radio could be a more sensible option for your first steps in DMR land, but only you can decide.

Useful links
Connect systems, the company that started it all.
VA3XPR did a very nice review of the CS700, highly recommended.
A DMR primer, downloadable from this blog (PDF)
Bamiporto.nl, the Dutch distributor. They also arranged this review sample.
Ready-To-Go code plug for the Netherlands: see Download section for the latest version.

Who is online? (Hytera Dashboard), (DMR Marc Network)
Call sign list (Complete), (Netherlands)

Connect Systems CS700 DMR handheld

When you focus too much on Chinese radios, which are supposed to be cheaper than anything else, you might miss something. I did miss something indeed, but thanks to Jason KC5HWB (click here) I can make up for my apparent tunnel vision.

I never heard of Connect Systems before, which caused me to miss a potential gem: the Connect Systems CS700 DMR handheld. This radio, fully compatible with Motorola and Hytera DMR radios, changes hands for around $180. I discussed the radio with PA0ETE, who is now in the process of acquiring two samples.

If all goes according to plan, we will share our findings with you as soon as possible.

CS700