IONOS HF/VHF/UHF Channel Simulator

Featured in the March/April 2022 issue of ARRL's QEX Magazine. BUY IONOS

The Amateur Radio Safety Foundation introduces the IONOS Channel Simulator, an audio-processing, 1-4 path (ray) simulator that models common HF and VHF/UHF propagation channels. It is intended to accelerate modem and protocol design, analysis, optimization and comparison, but has other uses as well. It allows off-air laboratory testing and evaluation of radio protocols and modems using statistically-standardized channel characteristics that would be almost impossible to achieve with over-the-air RF testing. Automation features allow scripting for multiple test runs under automatic control for huge time and labor savings. Since no transceivers are needed, the device may also be used as an inexpensive operator training station for exercising and teaching digital mode software. The simulator is based on the well-documented Watterson model [1] used by many laboratory grade instruments costing many thousands of dollars.

The simulator also performs an experimental BUSY DETECT function for research purposes. It provides a testbed for a much improved computer-controlled busy channel detection capability for fully automated stations. In this role, the device performs accurate and rapid spectrum analysis over a specified frequency band of interest. Optimization of the speed and accuracy of the busy detector algorithms continues. This function is not intended for manual user control so is totally controlled by serial commands sent between the device and a host computer. Appropriate computer software is required to participate with the Winlink Team in Busy Detect research.

An article on this device is expected to be published in QEX Magazine during February, 2022. Watch for it. The latest development information on this project is available on our GitHub project page:


Limited stock of fully-assembled IONOS units are available for sale now from the Amateur Radio Safety Foundation, Inc.

[1] Watterson, C.C., J.R. Juroshek, & W.D. Bensema. 1970 Experimental confirmation of an HF channel model IEEE Transaction of Communication. Technology. Vol COM-18. Pp 792-803 Dec 1970

Complete Technical Specifications and User Instructions are included in the Rev. 2.03 manual below.

Winlink Linkomatic