Three models, the ICOM R7000, Bearcat 250, and Regency K500, have the ability to automatically store active fre- quencies found during an unattended search operation. He left the antenna disconnected so the scanner would only respond to a transmitter in the immedi- ate vicinity. It's best to use a shielded cable to feed the scanner audio into the recorder rather than relying on the recorder's internal microphone. VOX recorders allow one to compress a whole day's worth of monitoring onto a single tape. When call letters are mumbled, I can play and replay the tape until I hear and understand them.
Test equipment can aid in the quest for new frequency information.
I've used a spectrum analyzer connected to an outside antenna, and a frequency counter for close-in work. One of the best parts of the hobby is sharing it with other radio buffs. Trading information with other hobbyists about frequencies, communication systems, and receiving equipment is more valuable than any pile of magazines. There are several regional chapters which hold regular meetings. Although the focus is on VHF and UHF ranges, there is coverage of HF utility stations below 30 MHz.