LARC ARES Simplex Tests
Version 5    

July 11, 2021 Mobile Simplex Test

This Simplex test operated differently than previous tests. Usually, all the participants do test transmissions, and everyone does a signal report on everyone else. However, in the latest test, only a couple of drivers with mobile radios did test transmissions. They started with each doing a test transmission at a central location, and then they drove 4 km away from the center of the city before doing their next test. We planned on having 4 drivers, going North, East, South and West in 4 km stages. However, only 2 drivers were available, so we did East and West.

As soon as one of the drivers finished his transmission, he started driving to his next location. While he was driving, we got back on the VE3GYQ repeater, and gathered basic signal reports from all participants. By basic I mean one of three assessments: Nothing heard, Weak signal, or Strong signal. Then we'd do the same process with the second driver. By the time he was finished, the original driver was close to, or at his next location, so there wasn't much waiting while drivers were in transit.

Our test simplex frequency was 147.57 MHz, the same as the fallback ARES simplex frequency. However, this is at the high end of the 2 meter band, and most antennas are optimized for the center of the band. In the future, we'll probably use 145.350, the transmit frequency of the VE3GYQ repeater, by having the mobile operators tune to the repeater, but press their reverse button for test transmissions. Having everyone always on the repeater frequencies will greatly simplify the process, and probably speed it up. (for reference, here's the 2 meter band plan)

We planned to stop when no one could hear the test transmissions any more (or when a driver encountered an ocean). However, we had participants who were a long ways East and West of the city, and they continued to receive strong signals as the drivers were close to them. The end actually came when we started having problems with the drivers being able to reach GYQ for coordination purposes, and we declared completion when they were 20/24 km out.

To answer the inevitable question "So, how did it go?" I have 3 groups of information:

  1. A results map, which includes a medium scale map showing all the test points, and the successfully communications paths to them, as well as a chart with info on each participant, including their signal reports. (There are explanations for parts of this file in the Observations, Conclusions and Lessons document.)

  2. A document titled "Observations, Conclusions and Lessons" with a bunch of musings on what went well, what didn't, why, and what we might do differently next time. This document is still being composed, but I'll throw in some random thoughts to start things off. Contributions welcome.

  3. A collection of maps, and a chart of the test transmission locations. These are intended primarily for our mobile drivers (who did a great job!).
    Driving maps: East-1, East-2, West-1, West-2, North-1, North-2, South-1, South-2
    A chart describing all test transmission locations.

January 27, 2021 Simplex Test on 146.400

Thanks to those who participated in the January 27, 2021 VHF test. Here are the results in a tabular form...


and in a geographical form...