Quote:
Originally Posted by dragoon500ly
The problem with microwave relay is it is a line-of-sight system, dependent on multiple towers which then form a chain that a smart villain could use to backtrack, and take out, your key bases.
Radio is basically omni-directional, unless you triangulate the broadcaster, but with frequency-hopping and encryption, that becomes harder to do.
I'm going with radio and satellite links only for the commo bases.
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I used to be an RF/microwave engineer before I switched to optics, so I am knowledgeable but also rusty.
To be clear, "radio frequency" generally refers to electromagnetic waves between 3 kHz and 300 GHz, which includes the 300 MHz-300 GHz section called "microwave". A microwave system is already a radio system.
Microwave is not inherently line-of-sight, the issue is simply that shorter wavelengths see more opportunities to scatter and fewer opportunities to coherently reflect. That is, you can transmit on microwave frequencies isotropically (in all directions) or directionally, it all just depends on the antenna. The range you get will depend on the antenna, the power, and some phenomena of the wavelength - at the most basic level, longer wavelengths see less attenuation and therefore have longer range. And all of this is just as true for the rest of the RF, too - if you have a 5 MHz radio you can transmit isotropically for a short range with a dipole or directionally for a longer range with a dish, all at the same power level. Also note that a communications system includes
two antennas, one on transmit and another on receive, and that more broadly
both sets of electronics determine whether or not the link closes. You can transmit directionally and I can receive isotropically, or vice versa, or we can both be on identical systems.
As for radio direction finding... that is a complex subject, and yes, one that the military works hard to prevent. But give me a couple of decent radios and power meters and I can do basic RDF on civilian systems, and add some decent computing power and I can make very good guesses on military.
I would not obsess over the precise technology used in the comm bases unless you are willing to actually do link budgets for them. Decide on the ranges and the directionality and that is all you will generally need.