Tags: hf, radio, propagation, perl

Posted: December 12, 2011

Visualising HF Propagation

Lately I’ve been playing around with using video as a means to produce a simple visualisation of HF propagation.

One of the problems of operating HF from a research station is that the times I can get on air tend to follow a very regular pattern. Working hours can be quite long, and even if I am not working the antennas may well be in use. As a result, the majority of my QSOs from Rothera were with US stations—especially from the Western side of the States—simply because of the time I tended to be on-air.

As part of planning for my time at Halley (the British Antarctic Survey’s other major research station) I wanted to branch out a bit and work a wider variety of places on different bands. In order to make the most of available openings, I needed to know which bands were open to where, at what times of day. Normally this kind of question would be answered by experience gained by long operation at a home QTH, or using prediction tools, but I decided to try empirical testing using WSPR.

For the past week I’ve been running WSPR using my FT-817 at 5W connected to one of the base antennas; running on each band of interest for just over 24 hours. A relatively straightforward Perl script then automates the process of merging the database downloaded from wsprnet.org into a single ‘virtual’ day and creating the video:

Want to make your own propagation video? Grab the script from github and get tinkering! The code was developed on OS X; it should work fine on any other Unix-based system, but I’m afraid your mileage under Windows is likely to vary. The only other things you’ll need are Xplanet to create the individual map frames, and ffmpeg to merge them into a video. For Mac users, ffmpeg is available from Homebrew. I’ve packaged Xplanet for Homebrew; but while it’s going through the acceptance process you can compile it for yourself very easily.