History of the Hepburn Tropo Index
created by William R. Hepburn, DX Info Centre
 My DXing background

  I first attempted to receive distant TV signals in 1970 as a kid playing around with rabbit ears in my hometown of Niagara Falls. My first DX (tropo) was seen in 1972 when I received Channel 11 Toledo, Ohio before our local Channel 11 came on the air. I started keeping a log of stations received on July 25, 1976. I had no knowledge of DX modes or that there were others who DXed. On that 1st morning, I broke the Toledo record by picking up Channel 6 Columbus, Ohio. Then on my 3rd day of organized DXing, I received Channel 3 Pensacola, Florida (to my dad's amazement), destroying the Columbus record. (I wrote to the address given in an news editorial and was pleasantly surprised to find a WEAR-TV QSL Card in the mail the next week!). After picking up Florida from Canada, I wondered just what the limit was (of course, that was E-skip). I later learned more about DXing from a copy of "Communications World" magazine. In that magazine, I learned of the "Worldwide TV-FM DX Association" (which I joined in early 1977) and learned about the various modes and what others were picking up. In 1981, I got my first taste of F2 skip with TV audio from the UK & France, and probable video from Ireland. Other modes such as Meteor Scatter and Aurora were stumbled upon as the years passed.

 The Tropospheric Ducting Forecasts  (a.k.a. "The Hepburn Charts")

  Using my many years of experience as a professional meteorologist and an avid radio/TV DX enthusiast, I began experimental text DX forecasts for the Toronto-Buffalo area in 1997 using E-mail. Once the Internet caught on, and the WTFDA (Worldwide TV-FM DX Association) formed a newsgroup, the forecast coverage eventually grew to cover all of Eastern North America. With continual gains in experience and real-time feedback from DX hobbyists, I was able to refine my methods and improve the forecasts. Later I developed the Hepburn Tropo Index - using my own proprietary algorithm - to attempt to quantify the strength of tropospheric ducting over different areas
. The algorithm uses raw weather model as input.

  In May 2000, I prepared my first forecast maps and the Tropospheric Ducting Forecast website was born. With maps rather than text, it was now easier to envision the zones with the higher potential for ducting. I created the maps by having a computer program emulate what I had been doing manually to prepare the text forecasts. As a result, I was able to expand the forecasts' coverage to encompass much of the world.
Over time, the index algorithm has been adjusted, tweaked and refined as real-time experience provides feedback. At the same time, the weather models themselves have improved, allowing better accuracy and finer resolution. For those wondering, Meteorological Service of Canada met models are used as input.

  The "Hepburn Charts" have been used around the world for 20 years, and continue to help a wide range of users that rely on forecasts of anomalous propagation.

2020 William R. Hepburn   www.dxinfocentre.com