Re: Propagation


Date: Tue Dec 19 1995 - 23:23:56 EST

Hi Bill,

At 18 minutes past the hour, WWV gives the solar flux index, the A and the K
indices, the conditions for the past 24 hours and the forecast for the next
24 hours. The report is updated every three hours at 0018z, 0318z, etc.

On 17 Dec at 1518z, the solar flux report was:
SFI=070 A=22 K=02, Last 24 hours: VERY LOW, QUIET TO UNSETTLED,
I worked a VO1 and KB7 from Michigan.

On 29 Nov at 2118z it was SFI=072 a=12 k-=00
I worked Sardinia and Brazil

Not alot of difference in the numbers

Based on my general knowledge (watching the SFI for the last 3.5 years). The
A index is how well the ionosphere has been the last 24 hours, a number
higher than 20 is bad, a low number is very good. The K index is the noise
figure for the next 24 hours.Usually 2 is decent, 1 is better and 0 is great.
thats the lowest solar noise level. Most of my DX has been worked while the K
index was at 0 or 1, occasionally at 2. When solar storms are raging, the K
index can be 4 to 6. I have rarely heard it over 6. I've found when the solar
flux number hits 90 or higher, the band is open to Russia and Japan at the
right time of day. I have not seen the SFI much above 90 since July 92 (when
i became active on HF again.) I missed the peak of the previous solar cycle,
so i plan on being around until the next peak and working DX until it comes
out of my ears.

Just because the solar flux is good doesnt always mean, you'll be able to
work DX, local thunder storm conditions can add an unbelieveable amount of
noise to the bands, making then practically useless. Even storm conditions on
the east coast can make the bands in Michigan terrible, when our local wx
doesnt seem that bad.

I always wondered why there wasnt any readable info on what to expect with
solar flux readings, I guess its because, its a continuously variable
phenonenom with so many variables that it cant be easily explained. Watching
the SFI and listening to the bands is probably the best way to learn about
it. There were times when the SFI was 74 and I worked throughout Europe,
other times I cant work Spain. The numbers are meerly an indication of what
could be.

72, Byron WA8LCZ

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