DX RX The Doctor of DX prescribes the answers to your problems, low and high, near and far. A how to of what for, by Mike(aka Billy)Graham, K7CTW

Holy Hashfist, Batman!

VHFers are a breed all their own, and they speak a different language. They use every trick in the book to extend the distance over which they communicate. I’ve seen (at Art’s place) the use of meteor scatter to make a QSO on 2 Meters. Here, two operators previously arranged a particular time and frequency for the attempt. Most often it was done by CW. They used the periodic meteor showers to “bounce” signals off the highly ionized meteor trails. The effect may only last for a few seconds or even less than a second, but in a meteor shower a QSO is possible by precise timing of when you transmit and when you listen. Art would transmit the first 30 seconds of each minute and the other station would transmit the last 30 seconds. Given a good steady flow of meteors, a valid QSO could eventually be completed. First, a rapid-fire repeating of the calls, then waiting for the return QSL, then exchanges of RST and confirmation, until finally both stations knew that they had completed the contact. I watched Art successfully use this technique with several midwest stations. Boy, have times changed!!

Today, a totally new set of techniques are being used by these fellows. With the advent and proliferation of personal computers, sound cards, software and digital tape recorders, many VHF DXers are making regular contacts on the VHF bands by means of High Speed CW Meteor Scatter (HSMS), even when there are no meteor showers. Because the earth’s ionosphere is constantly being bombarded with meteorites, even in non-shower times, it is possible to ‘leverage’ the bursts that do occur on a regular basis. If there were a way to ‘compress’ the data sent, meteor bursts of even 1/10th of a second are sufficient to pass meaningful information. Leave it up to hams to figure out a way to do it!! First of all, these hams don’t think in terms of Words Per Minute - instead, they work with Letters Per Minute (LPM), where 5 letters equals 1 word. About 1000 LPM (200 WPM) is the slowest speed used, and some fellows are operating at speeds of up to 4000 LPM (800 WPM) or even higher. Obviously, no one can copy CW at that rate, as it sounds like a ‘ping’. Enter the computer, sound card and software.

These Craig Breedloves of Morse have written computer programs which perform some of the following functions: