"Caveat Lector" wrote in message
news:g4V0f.353$i%.113@fed1read07...
ELF Extremely Low Frequency 3 - 30 Hz 100,000 - 10,000 km

SLF Super Low Frequency 30 - 300 Hz 10,000 - 1,000 km

ULF Ultra Low Frequency 300 - 3000 Hz 1,000 - 100 km

VLF Very Low Frequency 3 - 30 kHz 100 - 10 km

Hey, learned something new today. I didn't know these freqs had designations
other than LF...

Jackie