Wireless lavalier systems: frequencies, range and the failures you can prevent

A wireless lavalier gives you dialogue from anywhere on set, which is exactly why it is trusted too much. The link between transmitter and receiver is the weakest part of your chain, and it fails silently until you listen back.

UHF versus 2.4 GHz

Professional UHF systems tune across a wide band, so you can move away from local TV transmitters and other crews. They cost more and require frequency coordination. 2.4 GHz digital systems are cheap and simple, but they share a crowded band with every phone and router in the building.

• UHF: longer range, better in dense RF environments, needs scanning and coordination.
• 2.4 GHz: plug and play, fine in a quiet location, unreliable in venues and city interiors.
• Digital 1.9 GHz DECT sits between the two, clean but with limited channel count.

The habits that prevent dropouts

• Scan and coordinate frequencies at the location, not at the office.
• Keep line of sight between transmitter and receiver antennas where possible.
• Antennas vertical, receivers away from LED panels, laptops and dimmer packs.
• Fresh batteries per block, never per day, and write the change on the sound report.
• Walk the whole set with the actor before rolling and listen for the edges of coverage.

Always record a safety

Route the boom and each radio mic to their own tracks on the recorder, and add a mix track. When a lav drops out for half a line, the boom saves the take. That is the entire argument for multitrack recording and for keeping the poly file intact until post has looked at it.

What post needs from you

Name the tracks on the recorder so channel 3 arrives as LAV MARIE, not as track 3. Those names travel inside the file metadata and carry into a split, so the dialogue editor sees who is who without opening every channel. You can verify what the recorder actually wrote using the audio inspector before you leave the location.