The Communications Plan is what you should be considering frequently, this will be the organization of how you intend to communicate with your tribe if the lights go out, and maybe stay out. This should include all forms of electronic communication. If your tribe is spread across a large geographic area, your radio gear needs to be able to meet the challenge of providing reliable communications, if your crew are all nearby, you will not only enjoy the added comfort of having those you can trust nearby, but your radio gear wont have to be nearly as sophisticated.
Let’s touch on the subject of distance for a moment. If you have elements of your group hundreds of miles away, you will very likely need to be using HF radio gear to communicate with them. Frequency determines resonant antenna length, and by that, I’m saying that the lower the frequency, the longer your antenna needs to be, to effectively communicate. For example, a resonant 1/2 wave (we’ll get back to this in a minute) antenna for communicating in the middle of the 80 meter (we’ll talk more on this in a minute as well) band would be just about 66 feet long. Compare that to a similarly resonant antenna in the VHF range, lets say 2 meters and the antenna is just over 3 feet long. The higher the frequency, the smaller the antenna, by the same token, the higher the frequency, the shorter the range of communications.
I talked about resonant antennas, and meters a second ago, lets take a very brief look there. First of all, antennas for listening can be almost any length, typically the longer antenna, the more you will hear. But for transmitting, an antenna needs to be resonant, and in order for that to happen, a given transmitting frequency will have a very specific length antenna to be resonant. As the frequency increases, the length of the antenna shrinks. The fancy math to determine a 1/2 wave wire antenna is: transmit frequency divided by 468 for total length, total length divided by 2, for each strand of wire, traditionally arranged horizontally.
A half-wave antenna is half of a full wavelength for a given frequency. We’re getting too deep into technical mumbo-jumbo here, but we can safely say that half-wave wire antennas, created using easy to find wire (you can build a fully capable half-wave dipole out of speaker wire..) are absolutely functional, this should not be considered a poor substitute for a ‘real antenna’ this is very very real.
The above image also illustrates another huge advantages of the dipole.. It’s portability, aside from the transmission line (in my case, normal CB coaxial cable) the actual antenna wire and insulators can fit in your pocket.
I spoke about 2 meters and 40 meters earlier. Lets re-visit that. The amateur radio bands are categorized by some numerical value followed by ‘meters’ (ex: 160 meters, 80 meters, 40 meters, 17 meters, 10 meters, 2 meters, etc) This is simply a way to quickly refer to a chunk of the radio spectrum set aside for amateur use, and by using ‘meters’ it’s simply indicating that a ‘full wavelength’ for that specific portion of the radio spectrum is equal to the numerical value. (ie: 2 meters is indicating that a full wave antenna for this range of frequencies is 2 meters in length) and naturally, this is far easier to remember, and verbalize than saying ‘I’ll catch you tonight on the 144.00mhz – 148.00 mhz band!’
Okay, we’ve got some basic understanding of antenna requirements, and various radio frequencies, and how they behave over distance, in the next part of this post, I’ll explain why different frequencies react differently over distance, and then get into the meat and potatoes of implementing, and practicing your communication plan.