Antennas? Software-defined radio?
Wow, how did I end up popping up all of this from Wikipedia? Oh, I just asked a question one day, and I got my answer on Wikipedia. Yeah, in the past, this would have really went something more like I asked my question, and I wondered about it, but I never really got an answer. Yeah, technology can really change our lives. Change them for the better? I don’t know about that.
20160101/https://en.wikipedia.org/wiki/Software_defined_antenna
20160101/https://en.wikipedia.org/wiki/Radio_frequency
20160101/https://en.wikipedia.org/wiki/Cognitive_radio
20160101/https://en.wikipedia.org/wiki/RF_front_end
20160101/https://en.wikipedia.org/wiki/Antenna_%28radio%29
20160101/https://en.wikipedia.org/wiki/Antenna_%28radio%29
20160101/https://en.wikipedia.org/wiki/Digital_television
20160101/https://en.wikipedia.org/wiki/ATSC
20160101/https://en.wikipedia.org/wiki/Single_Frequency_Network
20160101/https://en.wikipedia.org/wiki/Very_high_frequency
20160101/https://en.wikipedia.org/wiki/Ultra_high_frequency
20160101/https://en.wikipedia.org/wiki/Rubber_ducky_antenna
To note. You ask, why do you need a longer antenna for lower frequency transmissions? Well, that is because of the photoelectric effect. Lower-frequency electromagnetic radiation has less energy associated with a wave of the same amplitude, so naturally, you are going to want to amplify it via a resonant antenna in order to get a sufficient amount of energy into your low-noise amplification circuit.
Oh yeah, and how does the discharge pattern of a capacitor work? It appears that there is a linear drop in voltage as the charge from the capacitor is drained.
20160101/https://en.wikipedia.org/wiki/Capacitor