Kalama Simplex Test

Last Saturday, I participated in a simplex testing exercise in Kalama, WA to determine communication capability in the absence of grid comms. The activity was sponsored by W7MSH - Mercury Mount St. Helens.

Eight tactical teams and net control spread out to a number of predefined locations in the area and checked in via 50w mobile 2m VHF to establish role. As net control proceeded to call the TAC stations, they would report their position by different available means (2m handheld, FRS handheld, GMRS mobile) as the other stations recorded a signal report from 0 to 3. After the called station completed their tranmissions, they alerted net control via 2m 50 watt.

After the complete roll call, teams would move to a different location and repeat the process.

After collecting all of the reports, we can better understand where stations should be located to maximize communication possibilities.


More pre-planning, written instructions, and scripts could have saved some time on the day of the exercise that could be spent testing more locations.

On the suggestion of a team member, the roll call for the 2nd and subsequent rounds was simplified by having each station test all of their modes when called by net control. Other stations were more likely to copy the initial, strong 50w mobile acknowledgement of the station and location and be ready to mark reports of each subsequent mode / transmission.

As a practice exercise, I think it would have been valuable to also play a game of telephone with each station having a codeword at each location and passing this along with their transmission. I think it would have made the experience more fun and prepared participants for relaying and traffic passing scenarios.

Broader participation, particularly with non-hams, would teach our family and neighbors better operating technique. Mobile stations operated by licensed amateurs are good relay points for dissmenating information across neighborhoods via widely available “bubble-pack” radios found in most households. Everyone should understand how to use and practice operating the equipment available to them should the need arise.


As a programmer I’ve been thinking of how simplex testing and emcomm exercises might be simplified and streamlined such that they could be performed more often and undertaken by those with less experience.

To that end, I’m writing a simplex testing app that allows users to create simplex “groups” consisting of “members” (operators) and “zones” (locations) of interest. A group can schedule an “exercise” at a certain date/time with a subset of members as participants, net control, and relay stations. An exercise would include one or more communications modes:

  • 2m (FT/aprs/digital)
  • CB
  • HF (voice/data)
  • etc

During an excersise, the interface would allow the operator to quickly enter signal reports and notes for the stations they can hear. As stations move, their location can be reported or updated automatically via GPS. If the station has internet access, the information would be synced and visible to the other stations, especially net control.

At the conclusion of the exercise all stations would connect to the network and sync their reports. The combined data would be visualized on a map with lines between stations indicating their communication capabilities.

The exercise station script, at minimum, would feature location and signal reports, and could include one or two way traffic passing.

The simplex “group” collects previous exercises and can be analyzed to provide suggestions for strong net control and relay station locations to best serve the groups’ members.

All of the information in the app should also be printable. In a grid down situation, a web app likely isn’t available, but the skills that are developed should be usable without other comms. This app is designed to make preparing for grid down comms easier to coordinate, it likely doesn’t provide much utility in an actual emergency.

Written on January 10, 2021


Right on, planning is so important, For the first try in many years to map out the reception areas (last one I remember was Kathlamet) I think the lessons learned were well documented. Perhaps you will be available to help plan and execute the next attempt to help gain a better outcome.

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