Audibility reports are based on data from the total number of signals monitored. Quality is rated as follows:
5 very good
4 good
3 acceptable
2 poor
1 unacceptable
Percentage of all short wave signals scoring 3, 4, or 5:
| |
2003/04
Actual |
2004/05
Target |
2004/05
Actual |
| Global |
83 |
86 |
81 |
| Africa and the Middle East |
86 |
87 |
83 |
| Americas |
77 |
76 |
64 |
| Asia and the Pacific |
83 |
85 |
82 |
| EurAsia |
82 |
88 |
81 |
| Europe |
90 |
93 |
86 |
Long distance transmission via the ionosphere is affected by many different factors, including the level of sunspot activity, which has
an approximately 11-year cycle. During periods of high sunspot activity, daytime transmissions can use higher frequencies, more of
which are allocated for broadcast use, whereas around sunspot minimum, which we are in at present, lower frequencies must be
used in order to reach the target areas. Congestion in these limited lower-frequency bands is a serious issue, as the additional
frequencies needed to ensure good audibility are often not available because they are in use by other broadcasters.
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Measuring our performance |
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Short Wave Audibility |
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