Re: Dead bands

Jerry N9AVY

Saw on station in TX whose 070# I needed, but "poof!" he was gone !.  Just not my day ...

jerry n9avy

On Tuesday, March 2, 2021, 01:09:02 PM CST, Matthew King - AK4MK <kk4cps@...> wrote:

There is a very large solar storm in progress.  The "A" index is *** 26 *** right now!  The "K" index is 4.   For reference, an "A" index over 11 is considered BAD.  The "K" index is considered BAD at 3, and VERY BAD at 5.

It's very handy to keep an eye on this data.  It's always on the home page.


Here's an excerpt from my QRZ page that explains a lot of what you see in the picture.  

Interpreting Solar Data

A” INDEX … 1-6 BEST 7-9 FAIR 11+ BAD - Represents overall geomagnetic condition of the ionosphere over a given 24 hour period.

“K” INDEX … 0 or 1 BEST … 2 OKAY .… 3+ BAD .…. 5 VERY BAD - This is the overall geomagnetic condition of the ionosphere averaged over the planet over the past 3 hours. K index indicates geomagnetic storms. Below 10 MHz, K of 5+ increases noise level appreciably, K of 7+ degrades HF significantly.

“SFI” … 70 NOT GOOD … 80 GOOD … 90 BETTER …100+ BEST - SFI is the Solar Flux Index and is a measure of total radio emissions from the sun.

  • Higher Solar Flux generally suggests better propagation on the 10, 12, 15, 17, & 20 Meter Bands. Solar Flux rarely affects the 30, 40, 60, 80, & 160
  • Generally, propagation conditions are best when the A index is 10 or lower, and the K index is 3 or lower.
  • SFI Solar Flux Index: When >70 then 20m opens. When > 90 then 15m opens.
  • X-Ray : Solar X-Ray emissions will cause shortwave fadeout. Classification from weak to strong X-Ray emissions : A, B, C, M, X
  • During a solar X-ray outburst, the lower frequencies are the first to suffer, with subsequent fading up the frequency spectrum over a short period (usually less than a hour). Signals crossing daylight paths will be the most affected (obviously as X-Rays come from the sun).
  • If you cannot hear signals there may be nothing wrong with your receiver or antenna. To see if a fadeout has occurred go to

070 #1708  

On Tue, Mar 2, 2021 at 1:51 PM Dave Tucker Nu4N <dwtucker19@...> wrote:
Well I have worked 2 on 40 this am and 1 on 20. Slim pickens.
Dave NU4N #1657 73's

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