Finding RF in your area. Use a Radio?
Then make an antenna and tune it to collect that energy.
Can have multiple antennas, in multiple directions to optimately collect various energies.
Question: Does SWR matter when you are only collecting (not transmitting) RF?
Answer, YES! But not because you want to efficiently transmit energy…
You want to find the HIGHEST standing wave (voltage) points to connect your FEA to. Lengthen or shorten your antenna to find the highest SWR voltage. This is the opposite of what you want for a transmitter.
Use open wire cables and adjust for HIGHEST SWR.
Tuning a Dipole Antenna (need a SWR meter or a voltmeter)
Building a MultiFrequency (fan) Dipole Antenna