HF Radio Propagation Modeling

Below is a series of cropped screen shots I collected at 0830 CDT today from the VOACAP map feature of the KE9NS PowerSDR software that I am currently using. My station location is marked with the red star. The predicted signal level scale ranges from blue (strongest) to green to yellow to orange to gray (weakest). Only the 30 m plot has gray contour lines. The 60 m plot has vertical lines that mark two of the defined frequency channels.

During earlier discussion of this topic, Tom KQ5S told us about the VOACAP propagation modeling presented on the K6TU web site. The link I provided here gives an overview of what's needed to run the model program on the web site.

A little web searching today about "do-it-yourself" VOACAP usage brought the following article from 2004:

An Introductory Tutorial to VOACAP

Two other search results raised my awareness of the VOACAP dependence on sunspot data and how it is defined and published:

• VOACAP Quick Guide  See the notes under the red text.
• The Sunspot Number

My searching today reminded me that the VOACAP capability is also a plug-in built into the 4nec2 antenna modeling software that I use. I've seen it in one of the program menus, but have not digested the documentation enough to use it.

John WA5MLF