VOX: Voice Activated Transmit

VOX (Voice-Operated Transmit) lets your radio key up automatically when you speak, without pressing the PTT button. It's designed for hands-free operation - useful when you need both hands for driving, hiking, climbing, or working.

How it works

When VOX is enabled, your radio's microphone continuously listens for audio above a set threshold. When you start talking, the radio automatically switches to transmit. When you stop talking, it waits a brief moment (the VOX delay) and then returns to receive. The whole cycle happens without touching the radio.

Sensitivity levels

Most radios offer adjustable VOX sensitivity, typically on a scale of 1 to 10:

• High sensitivity (low number): triggers on quiet speech. Good in quiet environments, but picks up more background noise
• Low sensitivity (high number): requires louder speech to trigger. Better in noisy environments, but you may need to speak up or speak closer to the mic

Start at a medium setting and adjust based on your environment. The goal is for the radio to key up reliably when you talk but not trigger on ambient noise. Test by speaking at your normal volume from the distance you'll actually be using the radio - don't test with the mic an inch from your mouth if you'll be wearing it on your shoulder.

VOX delay settings

The VOX delay (sometimes called "hang time" or "tail") controls how long the radio stays in transmit after you stop speaking. Most radios offer delay settings from about 0.5 seconds to 3 seconds. A short delay (0.5–1 second) makes the radio drop quickly between words, which can clip the beginning of your next sentence. A longer delay (2–3 seconds) keeps the transmitter keyed during natural pauses in speech, but wastes airtime and battery if you pause to think.

For most conversation, a delay of 1.5 to 2 seconds works best - long enough to cover natural speech pauses but short enough that you aren't transmitting dead air for long stretches. If you find the beginning of your sentences getting cut off, increase the delay. If you hear your radio staying keyed long after you stop talking, decrease it.

When VOX causes problems

VOX is convenient, but it creates issues in several common situations:

• Wind: even a light breeze across the microphone can trigger continuous transmissions. A foam windscreen helps but doesn't eliminate the problem entirely. In gusty conditions, VOX becomes unusable without a quality boom headset with a windscreen
• Vehicle noise: road noise, engine sounds, and rattles trigger VOX at higher sensitivity settings. If you use VOX while driving, you'll need to reduce sensitivity and speak louder, or use a noise-canceling headset
• Crowded environments: people talking near you, music, PA announcements - anything above the threshold triggers your radio. At a campsite, field day, or event, VOX picks up nearby conversations and transmits them
• Coughing and sneezing: these sudden loud sounds trigger VOX instantly and transmit sounds nobody wants to hear on the air
• Radio speaker feedback: if you're monitoring the channel through the radio's built-in speaker without an earpiece, incoming audio can trigger the VOX and cause a feedback loop. Always use an earpiece or headset when running VOX

VOX through repeaters

Using VOX on repeaters requires extra caution. Every accidental transmission ties up the repeater for all users in range. A VOX-triggered burst of wind noise or background chatter goes out to everyone on the repeater. Repeater operators notice and don't appreciate it. If you use VOX on a repeater, keep the sensitivity low enough that only deliberate speech triggers it, and switch to PTT if conditions get noisy. On busy repeaters during nets, PTT is strongly preferred since timing and discipline matter more. There's also a practical timing issue with VOX on repeaters: the radio needs a moment to key up and for the repeater to open before your first words go out. A lead-in word or a brief pause after the VOX triggers helps ensure your content is captured.

VOX vs PTT: choosing the right mode

The choice between VOX and PTT depends on your situation:

• VOX is better for: hands-free activities where you communicate frequently - driving, hiking with trekking poles, working on a job site, skiing, or cycling
• PTT is better for: controlled communication where you want to choose exactly when to transmit - repeater use, nets, monitoring channels, or any environment with significant background noise

Hands-free operation tips

If you rely on VOX for hands-free use, these practices will improve the experience:

• Invest in a quality headset with a boom mic and windscreen - this is the single biggest improvement you can make
• Develop a habit of speaking slightly louder and more deliberately than normal when transmitting, so the VOX triggers cleanly on your first word
• Say a brief lead-in word ("Hey" or "Break") before your actual message to let the VOX key up and the other station's squelch open before your content starts
• Monitor your own transmissions - if others tell you they're hearing wind or noise, switch to PTT
• Disable VOX when you're done communicating and just want to listen
• Use an earpiece or headset for receive so incoming audio can't retrigger the VOX circuit

If you find VOX unreliable in your environment, switch back to PTT. Most operators treat VOX as a situational convenience rather than a full-time setting. Also consider that accidental VOX transmissions can interfere with others on the channel - the busy channel lockout feature won't help here since VOX bypasses your awareness of channel activity.