tk75 - Computer Control Software for
the ICOM IC-R75 Receiver

Copyright 2003, Bob Parnass

IC-R75 photo


tk75 is open source software designed to control and program the ICOM IC-R75 receiver. An introductory article about this software was published in September 2002 Monitoring Times magazine.

I implemented tk75 in the Tcl/Tk scripting language. The free Tcl/Tk interpreter software must be installed on your computer prior to using tk75. This enables tk75 to run on a variety of operating systems, including Linux , openBSD, Microsoft Windows, MacOS X, and Sun Solaris. I have not tested it on other platforms, but it will probably work on them after little or no modification.

tk75 is distributed free of charge, but it is neither shareware nor in the public domain. tk75 is a copyrighted work released under the terms of the GNU General Public License as published by the Free Software Foundation. tk75 is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

Most IC-R75 controls are available on tk75's Main Controls window and Secondary Controls window . Less frequently used parameters may be accessed using the pulldown menus, which may be "torn off" and used as a separate window. tk75 provides control of virtually every Set Mode adjustment. A filter menu and filter configuration applet manages installation of optional filters and clearly associates IF filters with wide, medium, and narrow selectivity settings for each mode.

tk75 lets you scan memory channels and perform limit searches.

tk75 can be used to load the IC-R75 memories or read memory data from the radio and store it in a file.

Data files are in csv (comma-separated values) format, so users can create or edit them using spreadsheet or text editor programs.

tk75 software provides a facility to log and timestamp active frequencies and relative signal strengths to a log file in csv format. For example:


Memory Channel Files

tk75 can read files containing memory channel data. Using the mouse, you can click on a particular entry and tk75 will tune the radio and set the mode, skip and select flags accordingly.

You can also download the memory data from a file to the IC-R75, thus programming its memories.

A memory channel data file must be formated in csv (comma-separated values) format. The first line of the file should be this heading:


All the other lines should contain these fields:

Channel number: 1 - 99
Frequency in MHz
Mode: am, sam, usb, lsb, cw, cwr, fm, rtty, rttyr
Selectivity: wide, medium, narrow
select (optional)
Preamplifier (optional): preamp1, preamp2
Attenuation (optional): atten
Antenna (optional): ant1 ant2
Label (optional): 8-char name which should
	not contain a comma or quotation marks.

This is a sample memory data file:

1,0.6,AM,WIDE,"WMT Ceda",,,,
2,0.62,AM,WIDE,"WTMJ Mil",,,,
3,0.72,AM,WIDE,"WGN Chic",select,preamp1,,ant2
4,0.78,AM,WIDE,"WBBM Chi",select,,atten,ant2
5,0.85,AM,WIDE,"WAIT Cry",,preamp2,,ant1
6,0.89,AM,WIDE,"WLS Chic",select,,,
7,1.14,AM,WIDE,"WRVA Ric",,,,
8,1.16,AM,WIDE,"WYLL Chi",,,,
9,1.19,AM,WIDE,"WOWO Ft.",,,,
10,1.22,AM,WIDE,"WLPO Las",,,,
19,1.12,AM,WIDE,"KMOX St.",,,,

You can use a separate text editor or spreadsheet program to create, edit, and print memory channel files. You cannot create or edit memory channel data files within tk75.

Computer Interface Adaptor

You will need either a straight through or a null modem cable to connect the radio to your computer serial port. Whether you require a null modem or straight through cable depends on your particular setup and I cannot predict in advance which will provide the correct results.


Thanks to Bob Grove of Grove Enterprises for the loan of an ICOM IC-R75 receiver to develop this software.

Downloading and Installation

tk75 is undergoing development. To download a beta test version, including source code, click on the appropriate link to the left.

Revised December 12, 2003