[HCDX] Fw: Topband Propagation

["Thomas Giella KN4LF" <kn4lf@xxxxxxxxxxxxxxx>]

----- Original Message ----- 
From: Thomas Giella KN4LF 
To: a COL Topband E-List 
Sent: Tuesday, October 14, 2003 11:12 AM
Subject: Topband Propagation


Per W0AH's query:

I have the following on my propagation website at http://www.kn4lf.com/kn4lf5.htm . Read #4 and #5.

Here are some general guidelines concerning correlation of propagation indices to actual expected HF/MF propagation conditions. 
1.) Dropping indices numbers are better, except solar flux for HF. 
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, as the energy of photons at this frequency is to low on the order of one million times. 
2a.) For high frequencies a solar flux of 100 is okay, 150 better, above 200 best for F layer multi hop. 
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. 
8.) No current STRATWARM alert. 
9.) IMF Bz with a (+) 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. 


Then look at the propagation data below. You can see that the K index was very low for several days, allowing the Aurora Oval to retract latitudinally and allow the high latitude path to open up between Colorado and northern Europe.

At last check the Aurora index is now a 10, at the top of the scale and the Kp is a 6 which is a moderate geomagnetic storm. 

                                                                   Kp               Boulder K
      20031013 94.4 12 25 14.5 13 8-25 33233334 32234434 316-537       
      20031012 97.8 23 35 7.0 6 4-11 12132222 00113311 286-369       
      20031011 105.8 51 77 6.0 5 5-9 21212212 00111321 350-433       
      20031010 111.8 85 79 6.1 5 4-8 21122212 00003221 408-517       
     



Also I posted the following on other E-Lists on Friday October 10th. Topband propagation conditions can be forecasted.

----- Original Message ----- 
From: "Thomas Giella KN4LF" <kn4lf@xxxxxxxxxxxxxxx>
To: "a RSGB PSC E-List" <PSC.Committee@xxxxxxxxxxx>; "a HCDX Prop Channel" <propagation@xxxxxxxxxxxxxxxx>; "a NRC AM E-List" <am@xxxxxxxxxxx>; "a HCDX E-List" <hard-core-dx@xxxxxxxxxxxxxxxx>; "a Cumbre DX E-List" <cumbredx@xxxxxxxxxxxxxx>; "a ABDX E-List" <ABDX@xxxxxxxxxx>
Sent: Friday, October 10, 2003 11:15 AM
Subject: Propagation Outlook


> I would expect HF/MF radio propagation conditions to worsen beginning in the
> October 13-14th window. Recurrent Coronal Hole #063 will become geoeffective
> (Earth facing) by the 13th. 
During a previous geoeffective pass as #057 it produced a peak Kp index of 7
> and a peak Ap index of 129. As #052 it produced a 7/122.


73,
Thomas F. Giella, KN4LF
Plant City, FL, USA 
EL87WX

KN4LF 160 Meter Amateur Radio Resources & More:
http://www.kn4lf.com/kn4lf.htm

KN4LF Daily Solar Space Weather & Geomagnetic Data Archive:
http://www.kn4lf.com/kn4lf5.htm

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