The PiZero 2W spectrum recorder runs for 7 hours on two 18650s & a step-down 5V converter (which doesn’t seem to add measurable noise on HF). And of course the batteries are hot-swappable as the unit has its own small UPS battery. The only limitation is the amount of free space on the MicroSD card #PortableSDR #SDR #HF #Shortwave #SpectrumCapture #SpectrumRecording #AirSpy