CommsPreper is always of good source of descriptive videos on Field/Survival Communications and this one is no exception.
In a short time he demonstrates the parts and the setup of a field radio station.
Briefly described, he uses a HF radio connected to a laptop running RMS Express, a (digital) text messaging app. Usually there should be a modem like device between the too, called TNC, that transforms the digital PC signal to Analog and vice versa.
Next in the setup there is an Antenna Tuner, a device that –out simply- transforms the electrical characteristics of the antenna. In this case the Radio, an IC-7200 has the TNC build-in.NO antenna can work in many frequencies well, but with an antenna tuner we can make a good enough job.
Regarding the antenna, it is a Windom design, a wire antenna with two legs of different length that works good in many bands. It is set in an inverted V shape. That means it center is raised up with the help of the mast and the two lengths are angled to the ground with the help of guy lines.
Last, the wire that feeds the radio signal to the antenna is connected to the antenna’s center, but in the Windom it is not. it is connected off-center, making the two wires of a different length, hence the often heard term “off-center dipole”.
Image source: http://www.packetradio.com/windom.htm
During the operation demonstration, Commsprepper sends a digital signal to another radio that is waiting for it. And when the signal is transmitted he checks the SWR, a value that shows antenna loses. That is power not transmitted by the antenna, but reflected back to the radio.
We hope you found our description easy to comprehend. We aim to continue this way, bring the art of radio to communication to the layman.