What is The planetary A index? Why do shortwave broadcasters need this number?

SB PROP @ ARL $ARLP004

ARLP004 Propagation de K7RA

ZCZC AP04

QST de W1AW

Propagation Forecast Bulletin 4 ARLP004

From Tad Cook, K7RA

Seattle, WA January 26, 2007

To all radio amateurs

SB PROP ARL ARLP004

ARLP004 Propagation de K7RA

Low geomagnetic activity will be good for this weekend's CQ World Wide 160-Meter CW Contest. But there is currently a flare-spewing sunspot just around the Sun's eastern limb, and when it swings into view we'll see solar flux about 10 points higher than now, and briefly some higher geomagnetic numbers. The planetary A index for January 26-31 is predicted at 5, 5, 15, 20, 20 and 15.

What is The planetary A index? Why do shortwave broadcasters need this number?

It's a measurement of earths magnetic field's disturbance.

It varies from 0 to 400.

Magnetic field's disturbance produce electromagnetic radiation all over earth, and this creates noise in radio broadcast.. That is why it is necessary for broadcasters to determine how much noise can harm there broadcast contents.

What is The planetary A index? Why do shortwave broadcasters need this number?

http://www.swdxer.co.nr/ has an excellent page about this sort of thing. Report It