Robert J Morton
Robert J Morton |
A brief outline of the short wave (HF) broadcast radio bands is shown below. These may have been change since I wrote this and allocations may differ slightly between global regions. The colours for daytime propagation (lower) and night time propagation (upper) have the same meanings as on my propagation diagram.
| The 120 metre Tropical Broadcast Band 2300-2498 kHz (198 kHz wide)  | On the boundary between Medium Wave and Lower HF characteristics. Used for domestic broadcast from sunset to sunrise in tropical areas where medium wave is too crackley. |
| The 90 metre Tropical Broadcast Band 3200-3400 kHz (200 kHz wide)  | Tropical domestic (similar to above). |
| The 75 metre Tropical Broadcast Band 3900-4000 kHz (100 kHz wide)  | Used in Europe & Africa (longer reach). |
| The 60 metre Tropical Broadcast Band 4750-4995 kHz (245 kHz wide)  | Best band for tropical domestic broadcasting. |
| The 49 metre International Broadcast Band 5950-6200 kHz (250 kHz wide)  | Packed from late afternoon to an hour after local sunrise. Some weak signals in winter daytimes. |
| The 39 metre International Broadcast Band 7100- 7300 kHz (200 kHz wide)  | Europe & Asia (Also available to amateurs in Region 2). Most crowded band on the short wave. |
| The 31 metre International Broadcast Band 9500- 9900 kHz (400 kHz wide)  | The world's most heavily used international broadcast band. A transitional band; best during evening & night, but some stations can be heard during daytime - especially in winter. Stations to the West fade-in during the late afternoon progressing across to the east by early evening until a couple of hours or so after local sunrise. |
| The 25 metre International Broadcast Band 11650-11975 kHz (325 kHz wide)  | Provides stable 24 hours a day world-wide transmission paths for broadcasters with very powerful transmitters. |
| The 22 metre International Broadcast Band 13600-13800 kHz (200 kHz wide)  | Similar to the above, but favours the afternoon when lots of powerful competing stations can be heard. |
| The 19 metre International Broadcast Band 15510-15600 kHz (90 kHz wide)  | Offers good transmission across the night hemisphere. Also good across the daytime hemisphere for several years each side of solar maxima. |
| The 16 metre International Broadcast Band 17550-17900 kHz (350 kHz wide)  | Highly directional: stations from the east receivable from morning and early afternoon, swinging round to stations from the west by late afternoon and early evening. |
| The 13 metre International Broadcast Band 21450-21850 kHz (400 kHz wide)  | International broadcasters use this band only a couple of years or so each side of a solar maximum when it provides a superb transmission path across the daylight hemisphere. Abandoned the rest of the time. |
| The 11 metre International Broadcast Band 25670-26100 kHz (430 kHz wide)  | International broadcasters don't seem to make good use of this band, even when it is open world-wide during solar maxima. Transmissions can reach world-wide on very little power during solar maxima. |