|
This is another instance where "microwave" is often generalized. Any blanket statement that asserts that microwave is or isn't a secure medium is patently false. The degree of security depends on the power and frequency of the radio, the width of the beam and the type of information being transmitted. This is not as complicated as it may seem.
For instance, let's consider our most commonly purchased radio. It transmits in the 23GHz (gigahertz) band for typical path distances of 0-5 miles. The power output is only 60 milliwatts, considerably less than that of a cellular phone. Also, where cellular transmission is omnidirectional, a point-to-point microwave signal is tightly focussed to about a one and a half or two degree beam.
So then, consider that you've got a very narrow beam - far overhead, and at the outskirts of that beam ("side lobe energy") you have such infinitesimally low power that to tap into that energy would redefine the "needle in the haystack" cliche. And then you have to be able to convert the RF radio signal to the format that you're sending, whether that's voice, LAN data, video or all three. Even our most experienced RF engineer couldn't do it.
By contrast, lower frequency radios, say in the two to six gigahertz bands, can transmit at power levels of hundreds of watts (versus milliwatts). They cover single-hop distances of 30-40 miles producing a beam that can fan out hundreds of feet wide ("fresnel zone"), and with more detectable energy in the side lobes. Such factors raise the chances of surreptitious interception and so sensitive data on these paths should be encrypted.
|
