Interfacing a Radio for PC Control

Andy O'Brien, K3UK and Jim Hargrave, W5IFP

Many modern radios allow the radio CPU to be interfaced with software products.  Radios can send data about operating parameters, and can receive commands.  Many HF radios manufactured since 1990 can be interfaced to a computer via serial (Com) port connections. If your radio is capable of PC-to-Radio interfacing, this will enable many features within Logger32 that you will find useful.

This section contains general instructions. Some specific instructions are contained in other parts of the Helpfile.

Benefits of a Radio Connection with Logger32

Here is what Logger32 can do in PSK and RTTY mode when there is a radio communicating with the PC.  You should also read the sections on Macros, Hot Keys and Programmable Buttons as well as Direct Control of Radios.

Display radio frequencies on the analog frequency display in the Sound Card Data window (go to View, Frequency display, Display Frequency from radio)

Display radio frequencies on pane 3 of the Statusbar in the Sound Card Data window.

Set the transmit frequency to that of an Aux window by turning Net off and then clicking on pane 3 in the Aux window (see Communicating with PSK31 and PSK63 - Operating Split Frequency by Transmitting at an Aux Window Passband Frequency).

Automatically retune your radio so that you are transmitting a tone of a selected audio frequency while remaining on the same transmitted radio frequency (see the Align section of the Sound Card Data window).

Retune your radio to a favorite frequency using macros.

Set the receiver filter bandwidths using macros.

Select mode and sideband using macros.

Operate split frequency (separate transmit and receive frequencies) using Macros.

The Macros section has a list of all macros in Logger32.  The Direct Control of Radios topic discusses how to use those macros that are specifically designed to control the radio over the Com port.

Connecting a Radio to Your Computer and to Logger32

General information is provided here to interface radios to Logger32. Detailed interface instructions for some specific radios can often be found in the appendix for those radios.

You will need to refer to your radio instruction manual for details of the exact protocol used by your radio, the communications port (com port) settings, and the cable and interface requirements.

In Logger32, you must first configure a port to communicate with your radio.  Do this in the "Setup | Radio | Radio 1(2) configuration" menu at the top of Logger32.  You must do this first, and have your radio on before doing the next step.

ICOM and Ten-Tec Radios require a specific address for the radio type.  This address can be set within Logger32.  For example, here is how to set up an IC-751 in the Logger32 program, Click on Setup | Radio | Radio 1(2) configuration. Select “Icom (not IC-735)”. Input the radio address (in Hex), i.e., 1C for an Icom 751. Note: Do not include the “H”as Logger32 assumes the address is in Hex format.  For a Ten-Tec radio, you must set the “Icom address” to 04, which is the default port for all Ten-Tec radios, and also go to “Radio” and select Ten-Tec for radio type.

Note:  You must have your radio connected through a Com port, and have the port selected and communicating with your radio before setting radio type, or Logger32 may freeze and have to be closed via Ctrl-Alt-Del.

Radio Debug Window

To assist in setting up the communications and troubleshooting, there is a Radio debug window that displays the data sent to and received from the radio. You can activate this window by checking the box in the port Setup described above. You can also activate the debug window by right-clicking the “Radio #” box in the lower status bar and checking “Show radio debug window”.

Logger Bandplan

Not all radios return their mode when interrogated.  Also, when attempting to QSY a radio to a DX spot some guess work is required in determining the mode to put the radio on, i.e., is a DX Spot on 14080 a CW, or RTTY spot?  To address this difficulty, see the Logger32 Help Topic Setup Bands and Modes.

Polling Speed

You must set the speed which the software polls the radio for information.  The slower it is set, the more delay you will see when you change frequencies, but the less likely it is that you will overload your computer.

In Logger32, click “Settings | Radio | Radio 1(2) configuration” options to set the polling speed in milliseconds.  500 ms. is fairly fast and a larger number will slow down polling.

Logger32 communicates with a connected radio under the following conditions:

Polling: Logger32 automatically polls the radio for frequency and mode when the radio port is open. The polling speed is set in the Radio Port Setup. The polling is automatically suppressed during transmit except when "PTT by Radio Control" is selected in the "Sound Card | Settings | Radio PTT Options" .

FREQ: Clicking the word "Freq" on the Logbook Entry window will allow you to set the format for the frequency display.

BAND/MODE: Clicking on the Band or Mode button will open the Band/Mode window where the operator can select the conditions for Band, Mode and manual frequency logging. 

DX Spot: Clicking on a DX spot (in the DX Spots window) will read the current radio frequency (for later reference), and set the radio to the frequency/mode of the DX spot.


Reset: Clicking the Reset radio # frequency line on the DX Spots window will return the radio to its previous frequency/mode (before you clicked on a DX spot).


Sending DX Spots: When focus is in the Logbook Entry window, pressing Control_D will open the DX Spots window that will allow you to send the spot as well as add comments. In order to post a spot, you must be connected to a DX cluster, have a callsign entered in the call field and have a frequency listed in the frequency field.

Display Frequency from Radio

Click “Setup | Frequency”. Check “Show frequency Display & Log frequency”.  Logger32 will, if computer-radio communication is operating, display the frequency from your radio in the Logbook Entry window and it will enter the frequency into the logbook when the QSO is logged. Logger32 will use this information for your log and for transmitting information in a QSO. 


Mode and Band are the primary features that your radio will share with Logger32.  This information can then be used via the Macro feature. 


The following is a sample of the radio settings in the Logbook Entry window.





The following is representative of the radio frequency display on the Sound Card Waterfall/Spectrum display.



Using a Commercial Computer-Radio Interface

You can build an interface to provide hardware isolation and signal reduction in the audio line from the computer to the radio input.  The topic on Interfacing a Radio to the PC Sound Card provides the information you need.  This interface requires no power, but only operates in the transmit audio line.

The World Wide Web can help you find a commercial interface to operate between your computer sound card and the radio.  Some interfaces have features such as providing extra connectors and switches to allow you to switch between microphone and computer, and adjustable signal levels so you can set the computer audio at exactly the same level as the microphone audio.  Each model of interface is different, and you must read the instructions for the interface to see how to use it.

If your radio interface gets its DC power from the computer over the RTS, DSR, or DTR lines, it may not work properly with Logger32.  You should try to provide power from the radio or from an external power source.

Radio Settings

Check the Helpfile topic for your specific radio to see if it supports radio-computer communication and if so, what protocol is used.

If your radio is not listed, the following information may prove helpful. Manufacturers often use the same communication protocol for their complete line of amateur equipment. If your radio is not listed, the settings for a similar radio by the same manufacturer may work or prove a good starting point for experimentation. A good example is the ICOM series of radios. All ICOM radios that operate under "Icom CI-V" protocol will work with Logger32.