Re: [IRCA] Dst
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Re: [IRCA] Dst

Hi Neil,
 
Yes that's correct the Ap and Kp indices have dropped back down to normal levels but not for a long enough period of time. Also the background x-ray flux and Dst are just now getting back to a normal level too, so MF radio propagation levels have not improved yet.
 
There is not allot of information on the Internet about the Dst index and it's correlation to MF radio propagation conditions.
 
Here is a link to the near real time Dst: http://swdcdb.kugi.kyoto-u.ac.jp/dstdir/dst1/q/Dstqthism.html
 
 
 
Some other links:
 
 
 
 
73 & GUD DX,
Thomas F. Giella, KN4LF
Retired Meteorologist & Space Plasma Physicist
Lakeland, FL, USA
Grid Square EL97AW
27 57 26.5 N 81 56 46.6 W
----- Original Message -----
Sent: Wednesday, September 21, 2005 7:17 PM
Subject: Re: [IRCA] Tonight

Can you link me to where I can get more info describing how to use the Dst index ? 
 
I'll also point out that A and K were low last night, but AU effects lingered on here in IL. Even at 11 PM I had little low/mid band lat skip from the usual super dominent clears.
 
73 KAZ
----- Original Message -----
Sent: Wednesday, September 21, 2005 5:53 PM
Subject: Re: [IRCA] Tonight

Also the background x-ray solar flux is A9.7 and the Dst index is a -4, which are more reliable indicators of good MF propagation band conditions than the Ap and Kp indices.
 
 
Here are some general guidelines concerning correlation of MF propagation indices to actual expected propagation conditions.

1.) Dropping indices numbers are better.

2.) For medium frequencies a solar flux under 150, under 100 better, 70 is best for E layer multi hop.

Keep in mind though that the 10.7 cm (2800 mhz) solar flux index is not a "reliable" gauge of ionization in our atmosphere for F layer MF frequency refractions, as the energy of photons at this frequency is to low on the order of one million times. However most are used to solar flux and sunspot number and it's a hard habit to break. A better indicator is the background x-ray flux. See #7 below.

3.) Solar flux of at least 100 for E valley-F layer ducting mechanism.

4.) Previous 24 hour Ap index under 10, under 7 for several days consecutively is best.

5.) Previous 3 hour Kp index under 3 for mid latitude paths, under 2 for high latitude paths, 0-1 for several days consecutively is best.

6.) Energetic protons no greater then 10 MeV (10+0) for 160/120 meters and no greater then (10-1) on MF broadcast band.

7.) Background x-ray flux levels less than C1 for several days consecutively for 160/120 meters and less then B9 for MF broadcast band, A9 or less is best.

8.) No current STRATWARM alert.

9.) IMF Bz with a (positive number) sign, indicates a lesser chance of high latitude path auroral absorption/unpredictable refraction or scattering of MF RF signals, when the Kp is above 3.

10.) A -50 or better towards a positive number Dst index during the recovery time after a geomagnetic storm, as related to the Equatorial Ring Current.

----- Original Message -----
Sent: Wednesday, September 21, 2005 6:39 PM
Subject: [IRCA] Tonight

A=3!  K=0!
 
Grey line approaching at 1000 mph!
 
Tonight's the night to put on the cans.
 
Jim Hannah
10307
Sangean 818, barefoot

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