Topband: Re: FL DX & Topband Propagation

[Thomas Giella, KN4LF]

  I  and KK4SI easily worked 5B4MF and W4MZ worked 5H1RK from Florida's
central east coast last night. PW0T was also finally Q5 audible here at my
station in west central Florida. We are seeing the best propagation of the
season so far here in Florida, per my last 7 day medium wave propagation
outlook. I've managed to work 11 new countries in the past week but
unfortunately PW0T was not one of them.

KK4TR stated and asked.....last night did appear to be a horizontally
polarized night as opposed to the normal vertical polarization. PW0, middle
eastern(5B4's) and southern Europe were much louder on my
horizontal antenna than on the vertical. I wonder if the higher A and K
index
had anything to do with it???

Yesterday evening the Kp index reached 5 (Ionospheric Storm), due to a large
earth facing coronal hole.

Per my MW propagation theory notes at my sub website of
www.kn4lf.com/kn4lf8.htm ,

E Valley-F Layer Propagation Ducting Mechanism/Chordal Hop Propagation-

Most of the time medium frequency RF signals in excess of 3100 miles
propagate via the E Valley-F layer propagation mechanism or via the Chordal
Hop propagation mechanism. High solar flux values can aid in long haul
medium frequency propagation in excess of 3100 miles, as high solar flux
values ensure a strong F layer, half of the E Valley-F layer duct mechanism.
Typically the majority of transmit antenna's radiation must be focused under
30 degrees to enter the E Valley-F layer duct.

A note, high solar activity in the form of increased ionization created by
ultraviolet and x-ray radiation, can fill in the E Valley-F layer ducting
region with medium frequency absorptive ionization and interfere with the E
Valley-F layer ducting mechanism. In a sense the E/F layer duct is shut down
and the medium frequency RF signal can only propagate between the E layer
and land/ocean surface, with a higher angle and more signal loss.

Also Choral hop propagation, which in it's simplest "explained" form can be
described as a medium frequency signal traveling along the underside of the
F layer with no land/ocean/E layer intermediate refractions. A high Kp index
of 5 (Ionospheric storm) damages the F layer and disrupts Choral hop and the
E valley-F layer propagation mechanisms and once again the medium frequency
RF signal only propagates between the E layer and land/ocean surface, with a
higher angle and more signal loss and is received better on a low horizontal
dipole.


73,
Thomas Giella, KN4LF

Plant City, FL
Grid Square- EL88wx
CQ Zone 5
ITU Zone 8

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

KN4LF 7 Day Medium Wave Radio Propagation Outlook:
http://www.kn4lf.com/kn4lf5.htm

Florida Meteorological & Climatic Institute:
http://64.176.157.9/sub/fmci.htm

Giella Website Designs:
http://www.giellawoodsignandwebsitedesigns.com