How to Do a Radio Check (“How Do You Read?”)

Not sure your radio is actually transmitting? A radio check is the ten-second call that tells you — here’s exactly how to ask, and how to read the answer you get back. · 5 min read

Sooner or later you will key the mic and wonder: is this thing even working? Maybe it is a rented airplane you have never flown, maybe you just swapped a headset, or maybe you called someone and got dead silence. The fix is a radio check — a short, routine call that asks another station to confirm they can hear you and how clearly. It is completely normal; controllers and other pilots do them all the time. The only trick is asking the right station, the right way.

Who to ask (and who not to)

At a towered field, ask Ground or Clearance Delivery — not Tower, whose frequency you want to keep clear for active control. At a non-towered field, ask on the CTAF or UNICOM, and any pilot may answer. Never do a radio check on 121.5, the emergency frequency (“guard”) — it is not for testing. And if the frequency is busy, wait for a gap; a radio check is low priority and can hold.

The call

📻 ATC says “Five-Two-Kilo, read you five by five.”

🎙 You say “Palo Alto Ground, Skyhawk Five-Two-Kilo, radio check, how do you read?”

“Five by five” or “loud and clear” both mean you sound perfect.

The readability scale (1 to 5)

The answer usually comes back as a number from one to five, describing how readable you are:

1 — Unreadable
2 — Readable now and then
3 — Readable but with difficulty
4 — Readable
5 — Perfectly readable

So “five by five” means perfectly readable with a strong signal, and “loud and clear” is the same idea in plain English. Anything lower than a four or five is worth investigating before you fly into a busy environment — check your squelch, your headset connections, and that you are actually on the right frequency.

Non-towered radio check

🎙 You say “Palo Alto traffic, Skyhawk Five-Two-Kilo, radio check on CTAF, Palo Alto.”

Any nearby pilot may answer. Keep it short — you are borrowing a shared frequency.

💡 No answer does not always mean a broken radio — sometimes nobody is around to reply. Before you assume a failure, try a different station or frequency. If several stations can’t hear you, then start troubleshooting the radio for real.

💡 The only way this becomes automatic is saying it out loud, dozens of times, before you key a live mic. That is exactly what ATCpal is for — practice a quick radio check so you can confirm your radio anywhere, anytime. Practice it free at atcpal.app.

Practice this call out loud — free

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