Thursday, July 31, 2014

Handheld Transceiver Intercom Sytem for Your Whole Neighborhood

With crime rates soaring and police departments moving away from public safety and toward paramilitary operations, we are entering a time when neighbors will need to help look after neighbors.  More and more neighborhoods particularly in rural areas are showing interest in forming their own Mutual Assistance Group (MAG).  A critical factor in any neighborhood watch group or MAG is communications.

Even the least expensive dual-band ham radio transceivers have over 100 memory channels which can be numbered or named.  With the power of these little radios, your MAG can be spread out over a mile or two and still be in direct communications.  It functions as a wireless intercom system that covers a wide area with a per-unit price low enough that all your members can be in touch at all times.  Some of this functionality can be achieved with FRS, GMRS or MURS radios, but the number of channels available and thus the flexibility of the overall system is greatly reduced.

These little radios typically will have two Variable Frequency Oscillators (VFO's).  This essentially means there are two transceivers inside the unit and you can "watch" two channels simultaneously and transmit on either channel (one at a time).

One channel can be programmed as the primary communications channel for your MAG.  Everyone’s radio should be monitoring this channel on one VFO at all times.
 If your MAG has a repeater in operation, this would be a logical primary channel assignment.
 Power should be kept at close to the minimum required for reliable communications in order to limit the amount of attention you get from travelers.

In addition, one channel should be assigned to each individual or household within your MAG.
 This allows individuals to communicate directly without bothering the rest of the MAG.

In addition to allowing multipoint intercom functionality between MAG members, it could, with a few very minor modifications, allow communications with travelers who happen to be spotted either by your observation posts or electronic security systems.  For instance, if there is a barricade in a trail or roadway on the approach to your protected zone, you might put one of these radios out with concealed wires leading from the radio to a concealed microphone and speaker.  With the Voice Operated Transmitter (VOX) function enabled, there is no need for the person you are speaking to do anything but reply to your conversation.  You might even be able to listen in on the conversation as the travelers discuss how to interpret the barricade they are confronted with.   You have the opportunity to gauge what their intentions are and possibly the size and offensive capability of their group.

If you do make the decision to speak to the travelers, they have no way of knowing if you are watching them from the edge of the clearing or sitting at your control and communications center a mile away.  The advantage in being able to speak to these strangers should be obvious.  You can ask them for any news of what they have seen in the direction they are travelling from.  You might find that one or more of their group has skills your MAG could use.  All of which is done without risking anything more than the strangers knowing that someone is probably within a mile or two of them.

For instance, your patrols have hopefully been watching this group from a distance and should know something about the composition of the group.  If it is an adult couple with small children, I might feel compelled as a Christian to offer some assistance to them.  It might be a good idea to have a few jars of peanut butter and some bottles of water buried in various places within a short distance of the point where these strangers are standing while they talk with you.  These mini-caches should be well concealed, but with some distinctive mark that you can direct them to depending upon the size of their group.


  1. Power should be kept at close to the minimum required for reliable communications in order to limit the amount of attention you get from travelers. interfon bloc

  2. I absolutely agree with that. Whenever possible, wired solutions are almost always better. The one exception is that, once discovered, wires can be followed even when not in use.
    In addition to using flea powered transmitters for minimum RF footprint, I would advocate directional antennas whenever possible. A more sophisticated system might use digital burst transmissions to further limit the time your transmitters are available for radio direction finders like the handi-finder that can be purchased for a little over $20. U. S. This device connects to the antenna jack on your handheld receiver, so it is pretty much frequency independent.