PROPAGATION - by AD5Q HOUSTON, TEXAS -- JANUARY 1999


The solar flux peaked above 180 for the first time in the new cycle, but has dipped below 120 as I write my final monthly forecast. This series began in February 1988, and this article completes the collection with exactly 11 years of seasonal documentation. It has been a good run, and I have learned a lot in the process of writing the forecasts. I feel fortunate in that none have written to point out errors in the predictions. I know of none, though I am fully aware that my reporting on WARC bands and low bands has been superficial and inadequate - reflecting the deficiencies of my own station. Perhaps someone will pick up where I leave off - hopefully reflecting the DX perspective from a different continent or hemisphere.

An archive of the complete set of articles has always been available from my website, which will soon be reorganized so that articles from the last cycle can be selected by month and solar flux range for use in the current and future cycles. You will always be able to find an article from the last cycle that will forecast current seasonal trends in DX conditions. Other propagation gurus will continue to keep you posted on current conditions on the sun.

But -- the above paragraphs were off topic. It's January and nighttime covers the Arctic. Polar paths are difficult and certain parts of the world are hard to reach on all bands. The dip in solar flux to 120 is temporary, and we currently do not have good coverage into Europe in the morning on 10 Meters. A rebound in the flux would open a window to all of Europe, but paths to Russia will still be difficult from Texas because of the Arctic night. On 15 the openings are broader, and on 20 we get regular polar openings at sunrise and sunset. Polar openings on 20, however, are better at any other time of the year.

With a high solar flux, nightpath propagation returns to 20 beginning in February. This year, we can expect this improvement primarily during March - and hope for a flux above 175 in late February for the ARRL CW contest (and excellent running rates all night). 20 will be a nightpath band most of the year.

Currently, 40 is quiet and really excellent. European signals are loud all evening and well past midnight, with lots of activity. The quiet conditions will continue for another couple of months - longer at higher latitude s. Over the next several months, the most spectacular seasonal phenomenon will be the improvement in nightpath propagation on 15 Meters. This peaks in late spring, bringing Asian openings in the morning, Europe through th e evening, and polar openings almost round the clock. We can expect these conditions this year.

On 10, there will be some improvement in the spring as daylight spreads over the Arctic. Later in the spring (when 15 opens round the clock), 10 will deteriorate as summer approaches. Spring DX on 10 is so-so, and is most spectacular in the fall. This fall, with a certainty of higher flux levels, 10 will be at its best.

For January, early evening band closings on 20 are a problem. Still, this is the best band for reaching remote parts of the world that are usually worked via the north pole. These windows are narrow, and the Antarctic lon g path is often the best alternative into southern Asia.

So here I conclude this final propagation post - a nutshell summary of the exiting year ahead. For greater detail, find the complete series of articles at http://www.nol.net/~ids/prop.html

I thank you all.
73 & DX
de Roy, AD5Q

http://www.nol.net/~ids/prop.html
E-Mail: ad5q@kb5tes.#setx.tx.usa.na or ids@nol.net