Your “cheap” transmitter could have been pumping out many tens of watts in a wide spectrum of frequencies.
Basically what you have is a wire-free gizmo destructor.
No way! - its hard enough to get 10W from RF transistors in the first place, there certainly isn’t “many tens of watts”
available for anything else, and a cheap transmitter would not be using over-specced RF power devices, they cost…
(Speaking as someone who has built transistor and valve VHF transmitters). The spurious emissions from a 10W
transmitter would be small compared to what a mobile phone can generate, for instance. Its the 10W in-band
that is doing the damage.
If you set up a transmitting station and don’t pay attention to antenna / ground placement you are asking to
fry delicate electronics.
With only 10W just having a reasonable spacing from antenna to house wiring might be all that’s needed.
10W into 50ohms is 22V rms, but at the ends of the antenna wires the impedance is effectively a lot higher, and
voltages will be in the hundreds - thus the need for good spacing between antenna and sensitive circuitry, or good
grounding/screening around the sensitive electronics. Antennas need to be several wavelengths away from other
bits of metal anyway.