This small analog TV transmitter was found in an Electronics Now from the 90s. The range is around 20 meters, and the coils are according to the channel on which you want to receive the signal.
Yes, tunnel diodes can also be used in voltage regulators, as shown in this circuit from a Radio...
The gain of this circuit at 1 kHz [and 40 dB falling rapidly when the frequency deviates from this...
A frequency of up to a few kilohertz can be obtained with this oscillator. The frequency is given...