>>890165>a 500mW to 1W personal FM transmitter has zero chance of getting through unless you are literally in bumfuck nowhereThis is false, because an inverse square law governs radio power. What this means in plain English is that radio power drops very quickly over distance, so it's not hard for a local source to drown out a distant source, even if that distant source radiates at 50,000-100,000 watts effective. If you start to throw in stuff like directional antennas, it's not hard at all for small, low power transmitters to overwhelm distant sources.
This is one of the reasons that virtually all electronics are certified not to emit harmful interference- because even small emitters can wreck radio communications.
How about some concrete numbers? My downtown radio station radiates at 50,000 watts effective power, and is about 10km away. My neighbor happens to be about 10m away. The question is how much power do I have to transmit in order to jam the downtown signal?
A quick rough estimate- the downtown transmitter is 1000 times farther away than I am. If you use the inverse square law as an estimator, any signal coming from my house is automatically about a 1000*1000 = million times more powerful simply because I'm closer. To have the same effective power at my neighbor's house, I need about a 0.05 watt transmitter (50mW).
That's not an unreasonable number. FM stations with good antennas can broadcast for miles and miles on just a single watt. It doesn't take a lot of power. Note that this distance plays a huge role in the amount of power needed.
If my neighbor was:
10m away you'd need 0.05 watts
20m away you'd need 0.2 watts (4x more power)
30m away you'd need 0.45 watts (9x more power)
40m away you'd need 0.8 watts (16x more power)
50m away you'd need 1.25 watts (25x more power)
The real picture is a little more complicated because of various effects like what specific frequency, but the general idea is the same.
