Radiobeacon System Map for North Atlantic (1946)
| Radiobeacon System |
| FREQUENCY is given in kilocycles. |
| CHARACTERISTIC CODE is shown in combinations of dots and dashes. |
| UNITED STATES and CANADIAN radiobeacons, in general, are assigned group frequencies and definite operating minutes. The sequence within a group is indicated by a Roman numeral. Stations with the same sequence numbers transmit during the same minute. |
| The scheduled 10 minute periods of each hour of clear weather are not displayed on the map but is shown in the table of sequenced radiobeacons. For example, a clear weather schedule of 1-4 indicates that the characteristic code is transmitted during the first and fourth 10 minute periods of the hour. The last minute of each clear weather 10 minute period is silent. (See clock face diagram on map for definition of each clear weather period.) |
At the stations marked  the radiobeacon
and sound signal are synchronized for DISTANCE FINDING. |
Radiobeacons marked  are of low power for local use
only. They operate continuously on the frequency and they have special characteristics as indicated for each case. The
above notes relative to sequence, characteristic, and schedule do not apply to these radiobeacons. |
| The service range is a reliable average range as follows: |
| Class A: 200 Miles |
| Class B: 100 Miles |
| Class C: 20 Miles |
| Class D: 10 Miles |
Sequenced Radiobeacons
| 286 | I | Ambrose | Lightship | 3-6 | Yes |  etc. | B | 40 27.1 | 73 49.4 |
| 286 | II | Barnegat | Lightship | 3-6 | Yes |  | B | 39 45.8 | 73 56.0 |
| 286 | III | Fire Island | Lighthouse | 3-6 | No | | B | 40 37.8 | 73 13.2 |
| 288 | I | West Quoddy | Lighthouse | 1-4 | Yes | | C | 44 48.9 | 66 57.1 |
| 288 | II | Hen and Chickens | Lightship | 1-4 | Yes |    | C | 41 27.0 | 71 01.1 |
| 288 | II | Mount Desert | Lighthouse | 1-4 | Yes | | C | 43 58.1 | 68 07.7 |
| 288 | III | Brandywine Shoal1 | Lighthouse | No | | C | 38 59.2 | 75 06.8 | |
| 288 | III | Portland | Lightship | 1-4 | Yes | | B | 43 31.6 | 70 05.5 |
| 290 | I | Cross Rip | Lightship | 1-4 | Yes |  | C | 41 26.9 | 70 17.5 |
| 290 | I | Smith Point | Lighthouse | 2 | Yes | | C | 37 52.8 | 76 11.0 |
| 290 | II | Cape Henry2 | Lighthouse | Yes | | A | 36 55.6 | 76 00.4 | |
| 290 | III | Wolf Trap | Lighthouse | 2 | Yes | | C | 37 23.4 | 76 11.4 |
| 292 | I | Eastern Point | Lighthouse | 3 | No | | C | 42 34.8 | 70 39.9 |
| 292 | II | Cape Cod Canal Breakwater | Lighthouse | 3 | No | | C | 41 46.5 | 70 29.8 |
| 292 | III | Nobska Point | Lighthouse | 3 | No | | C | 41 30.9 | 70 39.4 |
| 294 | I | Matinicus Rock | Lighthouse | 2-5 | Yes | | C | 43 47.0 | 68 51.3 |
| 294 | I | Point Judith | Lighthouse | 3 | No | | C | 41 21.2 | 71 28.9 |
| 294 | II | Little Gull Island | Lighthouse | 3 | Yes | | C | 41 12.4 | 72 06.4 |
| 294 | III | Partridge Island (Can.) | Lighthouse | 1-4 | No | Three times | C | 45 14.4 | 66 03.3 |
| 294 | III | Scotland | Lightship | 3 | No | | C | 40 26.6 | 73 55.2 |
| 296 | III | Sambro (Can.) | Lightship | 1-4 | No | Three times | B | 44 21.8 | 63 25.7 |
| 298 | II | Stone Horse | Lightship | 1-4 | Yes | | C | 41 32.8 | 69 59.1 |
| 298 | II | Winter Quarter | Lightship | 1-4 | Yes | | B | 37 55.5 | 74 56.4 |
| 298 | III | Five Fathom Bank | Lightship | 1-4 | Yes | | B | 38 47.3 | 74 34.5 |
| 300 | III | Manana Island | Fog Signal | 1-4 | Yes | | B | 43 45.8 | 69 19.7 |
| 302 | I | Highland | Lighthouse | 2-5 | No | | A | 42 02.4 | 70 03.6 |
| 302 | II | Boston | Lightship | 2-5 | Yes | | B | 42 20.4 | 70 45.5 |
| 302 | III | Vineyard Sound | Lightship | 2-5 | Yes | | B | 41 22.8 | 71 00.0 |
| 306 | I | Cove Point | Lighthouse | 1 | Yes | | C | 38 23.2 | 76 22.9 |
| 306 | II | Montauk Point | Lighthouse | 3-6 | Yes | | C | 41 04.3 | 71 51.4 |
| 306 | II | Overfalls | Lightship | 1-4 | Yes | | B | 38 48.0 | 75 01.4 |
| 306 | III | Sandy Point Shoal | Lighthouse | 1 | Yes | | C | 39 01.0 | 76 23.1 |
| 308 | I | Cleveland Ledge | Lighthouse | 3-6 | Yes | | B | 41 37.9 | 70 41.7 |
| 308 | I | Cornfield Point | Lightship | 1-4 | Yes | | C | 41 12.9 | 72 22.2 |
| 308 | I | Western Head (Can.) | Fog Signal | 2 | No | Three times | B | 43 59.3 | 64 39.7 |
| 308 | II | Handkerchief | Lightship | 1-4 | Yes | | C | 41 29.2 | 70 04.0 |
| 308 | II | Lurcher Shoal (Can.) | Lightship | 2 | No | Three times | B | 43 48.5 | 66 31.8 |
| 308 | III | Seal Island (Can.) | Lighthouse | 2-5 | No | Three times | B | 43 23.5 | 66 00.9 |
| 310 | I | Execution Rocks | Lighthouse | 3 | Yes | | C | 40 52.7 | 73 44.3 |
| 310 | II | Brenton Reef | Lightship | 1-4 | Yes |  | C | 41 25.9 | 71 22.6 |
| 310 | II | Stratford Shoal | Lighthouse | 3 | Yes | | C | 41 03.6 | 73 06.1 |
| 312 | I | Chesapeake | Lightship | 1-4 | Yes | | B | 36 58.7 | 75 42.2 |
| 312 | III | Halfway Rock | Lighthouse | 3-6 | Yes | | B | 43 39.4 | 70 02.2 |
| 314 | I | Pollock Rip | Lightship | 2-5 | Yes | | A | 41 36.1 | 69 51.1 |
| 314 | II | Nantucket Shoals | Lightship | 2-5 | Yes | | A | 40 37.0 | 69 37.0 |
| 314 | III | Block Island Southeast | Lighthouse | 2-5 | Yes | | B | 41 09.2 | 71 33.1 |
| 1 | Operates continuously for calibration purposes in clear weather only. |
| 2 | Operates continuously 1 minute on, 2 minutes off, 24 hours daily. |
Marker Radiobeacons
| 290 | Governors Island Extension1 | Lighthouse | ½ sec. dash repeated for 13 sec., silent 2 sec. | D | 40 41.1 | 74 01.6 |
| 292 | Cape May West Jetty2 | Lighthouse | ¼ sec. dash repeated for 7 sec., silent 8 sec. | D | 38 56.0 | 74 52.0 |
| 300 | Fort Wadsworth1 | Lighthouse | ½ sec. dash repeated for 13 sec., silent 2 sec. | D | 40 36.3 | 74 03.3 |
| 300 | Newport News Middle Ground2 | Lighthouse | ½ sec. dash every sec. | D | 36 56.8 | 76 23.5 |
| 1 | Marker radiobeacon, operates for calibration continuously from 0600 to 2000 eastern war time daily. |
| 2 | Marker radiobeacon, operates continuously. |
