Real life communications have been interrupted by faulty sump pump motors and bad LED drivers. Actually trying to build a radio is no guarantee of success.
A long time ago, we were acquiring the shadiest RF devices possible to test against our WiFi routers, which should avoid auto-selecting interfering frequencies. One device we got was an analog wireless security camera thingie bought right from Amazon. "2.4GHz" it declared, so it was the perfect test case. We turned it on and there was no WiFi interference whatsoever. We got out the test equipment and... its carrier frequency was right on the edge of the L1 GPS frequency. You turn the thing on, there goes GPS for the neighborhood. It was impressively disastrous and we did not test it any further!
That's a company trying to build a radio product, for sale to consumers in the US market. I don't have a lot more faith in random people trying to build FM radios. Sure, you'll know if it doesn't work, because you tune your car radio to it and you can't hear anything. But unless you're careful, you can radiate a lot of power in the sidebands and the harmonics. That will trash licensed spectrum users, which is Not Nice Of You. (As for "amateur radio" operators, how to build and test radios is part of the exam, so there are a lot of great homebuilt radios floating around out there. Also part of the test is knowing when you can use non-amateur frequencies, and what the punishment for doing so is. Needless to say, not a lot of trained hams are building pirate radio stations. So that brings the likelihood of doing a bad job even higher; by definition, only the unlicensed and untrained are even trying this.)
This comment is already too long but I want to relay another fun fact. Building a receiver can interfere with other users of the spectrum; a common design mixes the incoming radio signal by a higher frequency, filters it, and then mixes it down to audio frequencies. If you don't shield this well, then your receiver is actually a transmitter on some random other band. Be careful and test your design with a spectrum analyzer. It's not rocket science but it's not trivial either.
A long time ago, we were acquiring the shadiest RF devices possible to test against our WiFi routers, which should avoid auto-selecting interfering frequencies. One device we got was an analog wireless security camera thingie bought right from Amazon. "2.4GHz" it declared, so it was the perfect test case. We turned it on and there was no WiFi interference whatsoever. We got out the test equipment and... its carrier frequency was right on the edge of the L1 GPS frequency. You turn the thing on, there goes GPS for the neighborhood. It was impressively disastrous and we did not test it any further!
That's a company trying to build a radio product, for sale to consumers in the US market. I don't have a lot more faith in random people trying to build FM radios. Sure, you'll know if it doesn't work, because you tune your car radio to it and you can't hear anything. But unless you're careful, you can radiate a lot of power in the sidebands and the harmonics. That will trash licensed spectrum users, which is Not Nice Of You. (As for "amateur radio" operators, how to build and test radios is part of the exam, so there are a lot of great homebuilt radios floating around out there. Also part of the test is knowing when you can use non-amateur frequencies, and what the punishment for doing so is. Needless to say, not a lot of trained hams are building pirate radio stations. So that brings the likelihood of doing a bad job even higher; by definition, only the unlicensed and untrained are even trying this.)
This comment is already too long but I want to relay another fun fact. Building a receiver can interfere with other users of the spectrum; a common design mixes the incoming radio signal by a higher frequency, filters it, and then mixes it down to audio frequencies. If you don't shield this well, then your receiver is actually a transmitter on some random other band. Be careful and test your design with a spectrum analyzer. It's not rocket science but it's not trivial either.