Annual SARL road show that takes you to the edge of amateur radio

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SARL Radio Technology in Action

To order the kit click here for the order form. Shipping starts 24 November 2014


Digital communication is an interesting and dynamic activity on the amateur  bands today. Modestly priced computers equipped with sound cards have brought about both non-traditional means to use traditional modes and the development of extremely effective new modes that would have been impossible 10 years ago. Transceivers available today are equipped to facilitate these operating modes. All that is necessary is to connect a digital communications interface between  the  transceiver and computer. For best results and fewest connection issues, this interface should match signal levels between the two and provide ground path isolation.

There are plenty weird and wonderful RS232 serial port designs, circuits and commercially available units (very pricey!!!) on the web and given that most modern computers and laptops today have no conventional RS232 serial ports, Frik Wolff, ZS6FZ  designed an affordable Isolated USB Transceiver Control Interface kit   with a combination of a USB to Serial Module. The kit uses conventional through-hole components which requires no previous experience to build.

Frik Wolff ZS6FZ will discuss the the project in details and demonstrate its use at the RTA.

The Isolated USB Transceiver Control Interface kit is a fully isolated interface between a transceiver and computer. It comprises a complete USB to Serial module and a bi-directional audio link between the sound card and the transceiver.

The USB control interface supports Icom CI-V, Kenwood and Yaesu CAT control ports on current transceivers. Visual (LED) indication of control data flow between the computer and radio and also the PTT or CW status of the radio are provided. An LED indicates “Power ON” from the radio.

The kit is compatible with many of the current generations of ham transceivers. The interface provides complete isolation between the transceiver and the computer, as well as complete isolation between both functions of the interface. Either side of the Isolated USB Transceiver Control Interface can be operated independently of the other.  

The USB port provides power for the USB interface module and associated opto-isolators. The transceiver supplies power for the transceiver side (PTT, CW and Leds) of the inerface. Power requirements are very low, less than 10 mA Voltage can be between 8 and 15 volts. No power is required for the computer side of the sound card interface.


A wide variety of freeware, shareware, and commercial digital mode software is available for you to choose from. This is a partial listing to get you started. It is by no means comprehensive and includes only HF digital communications packages. All have been tested with this interface but there is no reason to believe that other similar software will not work.

Ham Radio Deluxe by HB9DRV - logging, PSK31, PSK63, CW; TrueTTY - teletype;  MMTTY - teletype; MMSSTV - slow-scan television;MixW - PSK31; Olivia; DigiPan - PSK31, PSK63; DX4WIN - PSK31; Hamcom 3.1 - CW, RTTY, AMTOR; HamScope - PSK31; Hellschreiber; WinWarbler – PSK; WSJST plus many more!


This is an interesting, educational and affordable project. It opens the door for experimenting with soundcard modes, such as Pactor, TTY, Hellschreiber, and SSTV just to name a few. It is also useful for recording QSOs, Sunday bulletins or voice contest calls.

Building the Isolated USB Transceiver Control Interface kit is a breeze. A kit with a pre-drilled box and full description of how to construct it, will only be available at the RTAs.

Make sure you book for the RTA in your area in time. Booking open soon. Check the date for your area and get it into your diary

The kit will be available at R380 , book your kit when you register and take delivery at the RTA.  


Make a note of the dates.

21 June            Durban/KZN 

23 August        Johannesburg 

13 September   Pretoria 

4 October         Port Elizabeth 

1 November      Cape Town.