SB PROP @ ARL $ARLP043  

ARLP043  Propagation Forecast

ZCZC AP43

QST de W1AW

Propagation Forecast Bulletin 43 ARLP043

From ARRL Headquarters

Newington, CT  October 23, 2026

To all radio amateurs

SB PROP ARL ARLP043

ARLP043 The ARRL Solar Report

The active sunspot region that has been giving us improved propagation over the past several days will be rotating away from Earthís view today, but conditions on most of the HF amateur bands should remain pretty decent in the days ahead, as the 10.7-centimeter radio flux remains right around 100. However, NOAAís Space Weather Prediction Center (SWPC) says the geomagnetic field could become unsettled to active heading

into the weekend as a negative polarity coronal hole high-speed stream (CHHSS) heads toward Earth.

The Australian Space Weather Forecasting Centre predicts mostly normal HF propagation conditions worldwide.

The W3LPL Propagation Forecast from the Daily DX is predicting a dropoff in DX openings on 10 and 12 meters as the active sunspot region rotates away from Earth and the solar cycle continues its decline. However, good conditions are expected to continue on 15, 17, and 20 meters, with the lower HF bands (30, 40 and 80 meters) providing excellent long distance

nighttime propagation.

This weekend is the CQ World Wide SSB DX Contest (0000Z October 24 through 2359 Z October 25). Itís often said that this contest makes its own propagation, most likely because there are stations active to take advantage of unanticipated openings, even on the higher HF bands. So keep listening for calls from faraway stations.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, October 22, 2026, by F. K. Janda, OK1HH:

Solar activity is gradually declining in the second half of October, as expected. The decline will continue into early November, with Class C solar flares still occurring infrequently. Class M flares may continue to occur on rare occasions.

The next increase in solar activity is not expected until the second half of November. In the meantime, there will continue to be isolated and generally brief spikes in geomagnetic activity, which will be difficult to predict with precision.

The Predicted Planetary A Index for October 23 to October 29 is 5, 15, 8, 5, 5, 5, and 5 with a mean of 6.9. The Predicted Planetary K Index is 2, 4, 3, 2, 2, 2, and 2 with a mean of 2.4. 10.7 centimeter flux is 100, 95, 95, 95, 100, 105, and 105 with a mean of 99.3.

For more information concerning shortwave radio propagation, see www.arrl.org/propagation and the ARRL Technical Information Service web page at www.arrl.org/propagation-of-rf-signals. For an explanation of numbers used in this bulletin, see www.arrl.org/the-sun-the-earth-the-ionosphere. Information and tutorials on propagation can be found at http://k9la.us.

NNNN

/EX