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Introduction:

One of the biggest questions faced by ARES is "How do we alert ARES members to an emergency if the phones are out?" As the Connecticut ARES Leadership studied this question we pondered several solutions. We decided to use the European 1750 Hz Burst Tone. It will pass through any repeater as it is in the voice pass-band, and it is easily generated by many modern radios. It is easy to setup a tone decoder to determine when the tone is being sent through a repeater or simplex frequency.

We decided to pursue this idea using a tone detector kit. The circuit solution is based on the Ramsey Electronics TD-1 kit which sells for $9.95. (While one could get the parts through other sources easily enough, the Ramsey kit includes all the parts and a circuit board, thus making it very cost-effective.) It meets all the criteria of being inexpensive, reliable, a good club-night kit, easily setup with no test equipment other than a Volt-Ohm-Meter, etc. Rod Lane then developed the surrounding circuitry as shown in Figure One which causes the alert to latch so that if the user is out of the house when an alert is sent, when they come back there will be an alert indicator.

(For the entire article and plans, visit www.ctares.org, and look most of the way down on the left side.)