Radio check frequency, phrasing and the readability scale
A signal (or radio) check asks another station to rate your transmission on a five-point readability scale (RIC-21 5.7.5).
Request (RIC-21 5.7.5(1)-(2)):
- Call another aircraft or ground station on a frequency that will not interfere with the normal working of other aircraft or ground stations.
- Say "SIGNAL (or RADIO) CHECK 1, 2, 3, 4, 5. HOW DO YOU READ ME? OVER."
- Keep it to 10 seconds or less (RIC-21 5.7.5(4)).
Frequency:
- Where possible, request radio checks on frequencies other than ATC frequencies.
- Two-way contact with any agency is normally enough to show the radios work (RAC 4.2.3).
- Under tower control, request them on ground control frequency whenever possible (RAC 4.1).
ATS short form (checking with tower or FSS; NAV CANADA VFR Phraseology, Radio Check):
- Call: "(unit) (call sign) RADIO CHECK (frequency) / HOW DO YOU READ?"
- Reply: "(call sign) READ YOU (number)"
- Not for checks with another aircraft or ground station.
Readability scale (RIC-21 5.7.5(5)):
| # | Meaning |
|---|---|
| 1 | Bad (unreadable) |
| 2 | Poor (readable now and then) |
| 3 | Fair (readable but with difficulty) |
| 4 | Good (readable) |
| 5 | Excellent (perfectly readable) |
Names by timing (RIC-21 5.7.5):
| Name | When made |
|---|---|
| Signal check | While airborne |
| Preflight check | Prior to departure |
| Maintenance check | By ground maintenance |
Trap: mixing up adjacent readability numbers (2 vs 3, 4 vs 5); using the ATS short form instead of the numbered 1, 2, 3, 4, 5 sequence with another aircraft or ground station.
References
- RIC-21 5.7.5(1)
- RIC-21 5.7.5(2)
- RIC-21 5.7.5(4)
- RIC-21 5.7.5(5)
- NAV CANADA VFR Phraseology, Radio Check
- TC AIM RAC 4.1
- TC AIM RAC 4.2.3