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Adventures in Ham Radio

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KC3SMW

Adventures in Ham Radio

HF Propagation





Cheat Sheet:

SFI Solar Flu Index
< 70: propagation potentially bad.
80-90: propagation potentially are somewhat low
90-100: propagation tend to be average
100-150: propagation will tend to be good
>150: propagation will tend to be ideal

SN Sunspot Numbers
< 50: propagation conditions potentially very bad
50-75: propagation conditions attenuated
75-100: propagation conditions might be good
100-150: propagation conditions should be ideal
>150: propagation conditions possibly exceptional

A – index
1 – 5: Best conditions on 10-20 meter bands.
6 – 9: Average conditions on 10-20 meter bands.
10 < : Very Bad conditions on 10-20 meter bands.

K–Index
0 to 1: Best conditions for 10-20 meter bands.
2 to 3: Good conditions for 10-20 meter bands.
4 to 5: average conditions for 10-20 meter bands.
5 to 9: Very bad conditions for 10-20 meter bands.

Ap-index
1 – 5: Best conditions on 30-160 meter bands
6 – 9: Average conditions on 30-160 meter band
10 < : Bad conditions on 30-160 meter band

Kp-index
0 and 1: Best conditions on 30-160 meter bands.
2 and 4: Good conditions on 30-160 meter bands.
5 and 9: Bad conditions on 30-160 meter bands.

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