The MixW RigExpert USB CW and datamodes interface


[Note: This is a review of the first version of this product. It has now been superseded by newer models.]

I have been a keen user of PSK31 and other sound card data modes for many years, but for most of that time I have never used anything more sophisticated than simple home made interface cables to connect the radio to the computer. I could never really understand why people would pay a lot of money for products like the RigBlaster, when they could make up something that did the same job out of junk box parts.

I was even more perplexed after I realised that these RigBlasters didn't even support computer control of a transceiver. Operators who wished to use CAT still needed a separate CAT interface to connect the radio to the computer serial port. Since the commercial CAT cable didn't support CW keying, but the RigBlaster didn't support CAT, operators were having to install extra serial ports in their computer so the two interfaces could have one each, even though the two functions could be performed using one serial port.

After I began receiving weather satellite images on a regular basis, I found that my computer did not have enough sound cards or serial ports. Both my weather satellite receiving system and my radio setup needed a sound card and a serial port each. Rather than mess about with external sound cards and USB serial adapters - which would have created an appalling rats nest behind the computer and left me short of USB ports - I decided to buy a RigExpert. Designed and made in Ukraine by the developers of the MixW data mode software, which I also use, this elegant device requires just a single USB connection to the computer, and includes a dedicated sound card, serial port and CW keyer. It supports full CAT control, CW keying plus sound card data modes, and can be used with most ham radio software, not just MixW.


There are several different models of RigExpert. The RigExpert Tiny is the smallest and cheapest, but this is simply a CAT control and CW keying interface for users who lack an available serial port, and uses the computer's existing sound card. There is also the RigExpert Plus, the most up-market model in a handsome metal box, with level controls for the audio inputs and outputs and a speed control for the CW keyer. The original, basic RigExpert has the same functionality as the RigExpert Plus but without the controls and with a less sophisticated CW keyer. At the time of purchase there was also a model called the RigExpert Duo, which had two internal sound cards and is intended for use with transceivers having dual receivers. These last two models have been replaced by the RigExpert SD, a single model that can be programmed for use with one or two audio channels. This has also been accompanied by a price increase.

The basic RigExpert comes in a small black moulded plastic case. There are three LEDs, showing from left to right: Power (ON), CW (key down) and PTT (ON). There is also a 3.5mm jack for attaching a Morse paddle. There is lettering on the front panel which describes these functions, but it is unreadable as it has not been picked out in colour. Some RigExpert models sold in the US appear to have a computer-printed front panel which improves legibility, if not appearance.

The USB interface cable is included in the package. No power cable is needed, as the device is powered by the computer's USB port.

The RigExpert to radio interface cable must be ordered separately, or made up yourself. The connections differ according to the interface requirements of the transceiver it will be used with. There is a 25-pin computer D connector on the back of the RigExpert, which contains all the necessary connections, including support for the various transceiver CAT port voltage levels - RS-232, TTL and so on. The RigExpert website contains full wiring diagrams for all supported transceivers, so you can easily make your own, but as the price at the time was very reasonable, and long-sightedness has made soldering to D connectors rather a challenge, I opted to buy an Elecraft K2 interface ready made. The cables have gone up in price too, now, making the argument for making your own more compelling.


Connecting up the RigExpert was the easy part. Getting it going was more of a challenge, or would have been if I had not been very computer savvy. The main problem was that the instructions supplied were incorrect. They gave the impression that there was a folder containing the required drivers on the supplied CD, which you could point Windows at when it found the new hardware. In reality, there was a folder containing several Zip files, each containing drivers for various different RigExpert models. I had to find the correct Zip file, unzip it to a suitable folder, and then point Windows at that.

Configuring MixW to use the RigExpert is another trap that I fell into, though this was my fault due to following my own instincts instead of the instructions. The "gotcha" is that the RigExpert presents itself to the system as a serial port. This is not the serial port you use for CAT control of your radio, and you should not try to use it or fiddle about with its settings. MixW has a special configuration for the RigExpert, and you just need to tell it that's what you want it to use, and where it is, and it should all work perfectly.

A peek inside

picI'm reliably informed that the RigExperts are made in Ukraine, though they are probably shipped in knocked down form and assembled by the local agent. The product is very well designed and assembly would be extremely simple.

A single central screw holds the two halves of the plastic case together. Once separated, the plastic front and back panel sections are easily removed.

Three screws secure the circuit board inside the case. The circuit board itself is of very high quality manufacture, using surface mount devices. There are no user adjustable controls or trimmers on the circuit board, just a couple of jumpers and an unused header (possibly for the attachment of cables if the board is used inside a different case such as the RigExpert Plus.)

The plastic case and lack of any internal screening might be a cause for concern. I can only report that I have not experienced any problems due to RF pickup, despite using indoor antennas with the feedpoint about two metres directly above the RigExpert, albeit at QRP power levels.


picIn use, the RigExpert performed exactly as expected. Various reports I've seen suggest that the external sound card is of better quality, and has lower noise, than the internal sound cards fitted to many computers, giving a slightly cleaner signal and better decoding of PSK31 signals.

The CW keying works well, and was put to the test shortly after purchase in a spell of operating in the CQ WW WPX Contest. MixW was able to decode the high-speed Morse many of the contest stations were sending, and they had no trouble reading what was sent back to them.

One thing I discovered subsequently when attempting to call a station while MixW was not running is that the key (paddle) connection is not just a buffered parallel connection to the radio's own keyer, so you can't control your keying speed using the radio's keyer control. The RigExpert has its own internal keyer, and its keying speed is set by the MixW software. When MixW is closed, the keying speed remains set at the speed last set by the software. There is no way to change the keying speed if MixW is not running (unless you have the RigExpert Plus, which has a rotary control for this setting.)

The RigExpert can also be used with other ham radio software. Some people have reported instability issues with some programs, but in many cases this may be an incompatibility with the USB serial port, which can be a problem for a lot of software. A separate REAudio driver (supplied) must be installed, after which the RigExpert appears as a second sound card. You can then select this sound card as the audio input and output device in the software.

You can also use CAT with third party software. You just select the virtual serial port created by the RigExpert drivers. The developers list a number of popular ham radio programs that have been tested with the RigExpert. I have also used it successfully with my own K2Net software, without any modification, which suggests to me that if any program has a problem using the RigExpert, it is a problem with the program and not the RigExpert.

One thing I picked up recently on the web is that the RigExpert drivers will not install under the beta versions of Windows Vista. This may be because Microsoft is requiring drivers to be signed and certified by them - which I believe to be an expensive process. I don't know whether this will prove a problem for specialist products such as the RigExpert, for whom the cost of certification may prove prohibitive given the relatively small number of products sold. RigExpert users would be well advised to check this situation out before making a move to Windows Vista.

Remote control

The MixW RigExpert includes a program called TEOAN (Through the Eye Of A Needle) which allows the radio to be controlled remotely, over a network, using MixW. You run TEOAN on the computer connected to the radio, then run MixW on the remote computer and configure it to use TEOAN. It then works just it would if directly connected.

As far as I can understand, TEOAN streams the audio in uncompressed form over the network. This means that there is minimal latency, and the audio is encoded and decoded by the copy of MixW running on the remote computer. The disadvantage is that the bandwidth required is quite high, making it suitable for use on a local network, but not across the Internet. As there is no security or authentication support, Internet use would probably not be practical in any case.

Another disadvantage is that you cannot hear the audio on the remote computer: I have not found a combination of mixer settings that enable it to be played back over the speaker. This means that you can't work CW remotely, a disappointment that should be solvable with just a simple software addition to MixW to enable it to route the audio back out to the sound card.


The RigExpert is an excellent product for anyone who likes to use sound card data modes. It contains all the hardware you need to send and receive data modes, send CW and control the transceiver, and requires just a single USB connection to the radio. Despite the recent price increases, it's still a good buy when compared to the price of other radio to sound card interfacing products.

You have eQSLs waiting!
Enter your call and click Check

Locations of visitors to this page