Radiobeacon System Map for North Atlantic (1945)

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Radiobeacon System
FREQUENCY is given in kilocycles.
CHARACTERISTIC is shown in combinations of dots and dashes.
UNITED STATES and CANADIAN radiobeacons 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 out 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 (150 to 250)
      Class B: 100 Miles (50 to 150)
      Class C: 15 Miles (10 to 20)
      Class D (Marker Radiobeacons): 10 Miles (5 to 15)

Sequenced Radiobeacons

286 I 3-6 Ambrose Lightship Yes  etc.B 40 27.1 73 49.4
286 II 3-6 Sea Girt Lighthouse No A 40 08.2 74 01.6
288 I 1-4 West Quoddy Lighthouse Yes C 44 48.9 66 57.1
288 II 1-4 Hen and Chickens Lightship Yes C 41 27.0 71 01.1
288 II 1-4 Mount Desert Lighthouse Yes C 43 58.1 68 07.7
290 I 1-4 Cross Rip Lightship Yes C 41 26.9 70 17.5
290 I 2 Smith Point Lighthouse Yes C 37 52.8 76 11.0
290 II 2-5 Cape Henry1 Lighthouse Yes A 36 55.6 76 00.4
290 III 2 Wolf Trap Lighthouse Yes C 37 23.4 76 11.4
292 I 3 Eastern Point Lighthouse No C 42 34.8 70 39.9
292 II 3 Cape Cod Canal Breakwater Lighthouse No C 41 46.5 70 29.8
292 III 3 Nobska Point Lighthouse No C 41 30.9 70 39.4
294 I 2-5 Matinicus Rock Lighthouse Yes C 43 47.0 68 51.3
294 I 3 Point Judith Lighthouse No C 41 21.2 71 28.9
294 II 3 Little Gull Island Lighthouse Yes C 41 12.4 72 06.4
294 II 2-5 Overset Island2 Lighthouse Yes C 43 40.5 70 10.0
296 III 1-4 Sambro (Can.) Lightship No
Three times
B 44 21.7 63 24.5
298 II 1-4 Stone Horse Shoal Lightship Yes C 41 32.8 69 59.1
298 III Brandywine Shoal3 Lighthouse No C 38 59.2 75 06.8
300 III 1-4 Manana Island Fog Signal Yes B 43 45.8 69 19.7
302 I 2-5 Highland Lighthouse No A 42 02.4 70 03.6
302 II 2-5 Boston Lightship Yes B 42 21.4 70 43.2
302 III 2-5 Vineyard Sound Lightship Yes B 41 22.8 71 00.0
306 I 1 Cove Point Lighthouse Yes C 38 23.2 76 22.9
306 II 3-6 Montauk Point Lighthouse Yes C 41 04.3 71 51.4
306 II 1-4 Overfalls Lightship Yes B 38 47.1 75 00.7
306 III 1 Sandy Point Shoal Lighthouse Yes C 39 01.0 76 23.1
308 I 3-6 Cleveland Ledge Lighthouse Yes B 41 37.9 70 41.7
308 I 1-4 Cornfield Point Lightship Yes C 41 12.9 72 22.2
308 I 2 Western Head (Can.) Fog Signal No
Three times
B 43 59.3 64 39.7
308 II 1-4 Handkerchief Lightship Yes C 41 29.2 70 04.0
308 II 2 Lurcher Shoal (Can.) Lightship No
Three times
B 43 48.4 66 31.9
308 III 2-5 Seal Island (Can.) Lighthouse No
Three times
B 43 23.5 66 00.9
310 I 3 Execution Rocks Lighthouse Yes C 40 52.7 73 44.3
310 II 1-4 Brenton Reef Lightship Yes C 41 25.9 71 22.6
310 II 3 Stratford Shoal Lighthouse Yes C 41 03.6 73 06.1
312 III 3-6 Halfway Rock Lighthouse Yes B 43 39.4 70 02.2
314 II 2-5 Block Island Southeast1 Lighthouse Yes A 41 09.2 71 33.1
 1 Temporarily operates continuously 1 minute on, 2 minutes off, 24 hours daily.
 2 Operates only by specific order of Naval Authorities, Portland, Maine, until further notice.
 3 Operates continuously for calibration purposes in clear weather only on request of the Commandant, 4th Naval District.

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 ¼ 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 repeated for 10½ sec., silent 4½ 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.