Ham Fair 2005 - K9LA

Solar Cycle 23 and Early Predictions for Solar Cycle 24

Carl Luetzelschwab K9LA

Ham Fair 2005 - K9LA

Cycle 23

• Maximum smoothed sunspot number of 121 in early 2000

Cycle 23

0

40

80

120

160

Oct-96

Oct-97

Oct-98

Oct-99

Oct-00

Oct-01

Oct-02

Oct-03

Oct-04

Oct-05

Oct-06

Oct-07

smo

oth

ed

su

nsp

ot

nu

mb

er

data to-date predicted decline

we are here

• Secondary peak in late 2001

– Great 6m F2 DX!

• Minimum expected in late 2006 / early 2007

• We’re about a year and a half from solar minimum

solar minimum

Ham Fair 2005 - K9LA

The High Bands: 10m, 12m, 15m• At solar minimum, F2

openings on 15m to NA and EU will be of short duration

data from ARRL Antenna Book CD

• At solar minimum, no openings on 10m predicted to NA and EU

• If 15m is open, check 12m

Openings from JA on 15m

0

4

8

12

16

20

24

EU SA AF OC NA

nu

mb

er

of

ho

urs

in

th

e d

ay

solar minimum

solar maximum

Openings from JA on 10m

0

4

8

12

16

20

24

EU SA AF OC NA

nu

mb

er

of

ho

urs

in

th

e d

ay

solar minimum

solar maximum

winter month

winter month

Ham Fair 2005 - K9LA

17m – A Good Place for a Band• Prior to the WARC

band allocations, 20m was the workhorse band for long haul DXing around solar minimum

predictions for JA to indicated area (December around solar minimum)

G 0700-0800 UTC (low probability)

I 0600-0830 UTC

W2 no opening

WØ 2130-2200 UTC (low probability)

W6 2130-0030 UTC

PY 2200-0700 UTC

LU 2030-0900 UTC

HZ 0300-0900 UTC

VK4 2130-1530 UTC

CN 0730-0800 UTC (low probability)

ZS6 2230-1030 UTC

data from W6ELProp

Working Peter I on 17m3Y0X Feb 2006 2100-0930 UTC

• Get on 17m!

• 17m has the long haul characteristics of 15m, but the MUF need not be as high

Ham Fair 2005 - K9LA

80m and 160m

• Geomagnetic field activity is quietest at and a couple years after solar minimum

# of Days in Month With Ap < 7 vs Smoothed Sunspot NumberCycle 21 decline through Cycle 23 decline

0

40

80

120

160

200

Jan

-82

Jan

-84

Jan

-86

Jan

-88

Jan

-90

Jan

-92

Jan

-94

Jan

-96

Jan

-98

Jan

-00

Jan

-02

Jan

-04

Month, Year

sm

oo

thed

su

nsp

ot

nu

mb

er

0

5

10

15

20

25

# d

ays i

n m

on

th w

ith

Ap

< 7

quietest quietest

data from K9LA

• Most severe impact is to paths that go to high latitudes (those through and near the auroral oval)

– JA to WØ

– JA to W1, W2, W3

Ham Fair 2005 - K9LA

30m and 40m

• Propagation on 160m and 80m is dependent on absorption

• Propagation on 20m, 17m, 15m, 12m, and 10m is dependent on MUF (maximum usable frequency)

• 30m and 40m are transition bands – not as dependent on absorption and not as dependent on MUF– Of all the bands, they probably change the least over a

solar cycle

Ham Fair 2005 - K9LA

Things To Do At Solar Minimum

• Watch for north-south paths on the higher bands

• Monitor the Sun for unusual sunspot activity that could help the higher bands

• www.dxlc.com/solar, sec.noaa.gov, spaceweather.com, etc

• Participate in contests• www.ncjweb.com/contestcal.php

• Get on the low bands

Ham Fair 2005 - K9LA

All Recorded Solar Cycles

• Data is cyclic in nature

• We’ve lived through the highest recorded solar cycles

• It sure looks like we’re headed for an extended period of low solar cycles

our lifetime

Ham Fair 2005 - K9LA

Cycle 24 Prediction

• As Cycle 23 winds down, we’re seeing more and more predictions from the scientific community

from Schatten

• Most predict that Cycle 24 will be no greater than Cycle 23

• Some are even predicting a maximum smoothed sunspot number of around 75

– Haven’t seen anything that low since Cycle 16 (1923 – 1933)

Ham Fair 2005 - K9LA

Summary

• About a year and a half from solar minimum

• Stay active on the higher bands– Watch for sporadic E and north-south F2 propagation

– Monitor solar activity for unusual sunspot activity

– Participate in contests

• Get your low band station ready– 2006, 2007, and 2008 should be good years