NDB navaids
Non-Directional Beacons — low/medium-frequency beacons flown with an ADF. 6,610 on record.
| Ident | Name | Country |
|---|---|---|
| ONO | Oostende | 🇧🇪 BE |
| DD | Oostende | 🇧🇪 BE |
| OP | Op | 🇮🇪 IE |
| KS | Opalikha | 🇷🇺 RU |
| 2M | Opapimiskan Lake | 🇨🇦 CA |
| AO | Opera | 🇭🇺 HU |
| OA | Opera | 🇭🇺 HU |
| A | Opera | 🇭🇺 HU |
| O | Opera | 🇭🇺 HU |
| VI | Opery | 🇺🇸 US |
| AU | Opole | 🇺🇸 US |
| OPA | Oppaker | 🇳🇴 NO |
| OP | Opuwa | 🇳🇦 NA |
| VO | Ora V9 | 🇱🇾 LY |
| ORA | Oradea | 🇷🇴 RO |
| ORA | Oran | 🇦🇷 AR |
| ORG | Orange | 🇫🇷 FR |
| ORG | Orange | 🇺🇸 US |
| ORE | Orange | 🇺🇸 US |
| ORG | Orange | 🇦🇺 AU |
| ORC | Orange City | 🇺🇸 US |
| OYI | Orangeburg | 🇺🇸 US |
| RRJ | Oranj | 🇺🇸 US |
| OR | Orapa | 🇧🇼 BW |
| ALJ | Orca Bay | 🇺🇸 US |
| DNO | Orcadas Del Sur | 🇦🇶 AQ |
| UR | Orchy | 🇺🇸 US |
| ODX | Ord | 🇺🇸 US |
| EN | Orebro | 🇸🇪 SE |
| RB | Orebro | 🇸🇪 SE |
| QD | Orel | 🇷🇺 RU |
| UY | Orel | 🇷🇺 RU |
| PW | Orham | 🇺🇸 US |
| ORI | Orio Al Serio | 🇮🇹 IT |
| ORI | Orito | 🇨🇴 CO |
| OAN | Orléans | 🇫🇷 FR |
| OR | Ormara | 🇵🇰 PK |
| OVE | Oroville | 🇺🇸 US |
| ORB | Orr | 🇺🇸 US |
| SF | Orsk | 🇷🇺 RU |
| OR | Orsk | 🇷🇺 RU |
| VVV | Ortonville | 🇺🇸 US |
| ORU | Oruro | 🇧🇴 BO |
| CS | Osa | 🇷🇺 RU |
| RK | Osaka | 🇯🇵 JP |
| OK | Oscar Kilo | 🇮🇸 IS |
| OSE | Oscarville | 🇺🇸 US |
| OEO | Osceola | 🇺🇸 US |
| BPW | Osceola | 🇺🇸 US |
| DZ | Osh | 🇰🇬 KG |