April 9, 2016


One of the least understood areas of radio for most is the subject of RF propagation. Most propagation is based on a 11 year solar cycle. How much a radios energy will either be absorbed or refracted due to the relationship between the earth and sun is an amazing science.

We have so many variables involved in  propagation. The major one being the year in reference to the current solar cycle. The month of the year. The time of day. Then we have our location along with the transmitted frequency in use & your antenna. These all play a vital role in being heard or picking up broadcast stations.

It can be broken down even further with buzz words such as Solar Flux, K & A Index's along with the number of sun spots. I am by no means an expert on the subject of propagation. I'm what you would call a newb or newbie. I know the basics but have been reading as much as I can about it and I find myself checking propagation forecasts charts regularly and really enjoy learning about it.

 I came across an app called VOAProp which was written some time ago by Julian Moss (G4LIO), Julian built a front end propagation forecaster that sits on top of the world class VOACAP HF propagation prediction software written by the NTIA/ITS for the Voice of America. VOAProp kills two birds with one stone. VOAProp will try and predict propagation for the shortwave listener along with predicting propagation for the amateur radio operator for any given band based on your location and antenna in use.

In order to get VOAProp running on your machine you will need to have VOACAP installed first. Both programs must be installed in the root folder of C:\ and without spaces in the folder names you choose. You can not use C:\ Program Files or C:\ Program Files (x86). I have them both installed in C:\Ham. The install files are available at the following locations.

VOACAP http://www.greg-hand.com/versions. Scroll to the bottom of the directory and click on the latest files itshfbc_151021.exe to download.

VOAProp http://www.g4ilo.com/voaprop.html. Scroll to the bottom and select Download VOAProp 1.1 Setup (1Mb)

Installation for VOACAP require zero configuration from the end user. Install it and leave it alone. For VOAProp you will need to do the follow by right clicking on the map,

Important Note: 

Main settings

Home location. Right click on the map and select Set home location. Enter your Latitude & Longitude or your Grid location. Having your grid location is the easiest method.

Solar Data. Click on the Solar Data button. Cut and paste this into the Data URL: http://ok1dub.cz/wwv/wwv.txt  Put a check in the Auto update box and click Update. Click the Close button.

Shortwave or Amateur use: Right click on the map and select from the first two choices Amateur bands or Short wave bands. (both are based on the Home location you provided in step 1)

Misc: Right click on the map and select Show signal Strengths (for the bottom right color bar on the main screen) & select Show UTC time in the title bar

Main screen settings.

High Medium and Low slider. This is for use in the Amateur bands of the program predictions and they are based on the following output power and antenna being used, This is a rough guide, you can take High as 4KW+tower mounted beam, Medium as 100W+dipole, Low as 1W+low dipole. I usually have mine set to medium.

Auto-Update. You will not have to input Date, Year & time. If you want to look at future predictions just select the month and the time. Remember to re check Auto Update to have a near real-time forecast.

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