- AURORA BEACON
clubstation of Deutscher Amateur Radio Club HF committee, DARC district
Schleswig-Holstein DL0CS - Radioclub Suederbrarup, DOK M15.
The team of operators: DD7HA, DK4LI, DK4VW, DL2FJ. Locator: JO44VQ. There are transmissions on the
80 m and 30 m
80m: 3579 kHz (main frequency),
3567 kHz (first alternative) or 3557,5 kHz
(second alternative). The frequency is chosen depending on QRM-situation by commercial stations.
are requested not to use these frequencies during the hours of
operation - especially not to run automated BBS systems outside the
digi mode range ( f < 3580 kHz) since the beacon has got a status
like e.g. fm-repeaters on VHF/UHF by the German Licence Authority.
80m: time of transmission
7-8 UTC and 15-18 UTC
10144 kHz . Time of transmission
The "normal" loop of transmission
DK0WCY BEACON _____________ (followed by a carrier).
In case of radio aurora
DK0WCY BEACON ................ AURORA (dots).
If a very strong radio aurora event is observed:
DK0WCY BEACON ................ STRONG AURORA
Every full 5 minutes the result of local
measurements of the geomagnetic field by a magnetometer, a forecast of
expected solar activity
SUNACT and geomagnetic field status
MAGFIELD, the observed sunspot number R (also known as
SSN), in Penticton/Canada at 2800 MHz measured solar flux -
FLUX, and the index A of the magnetic field
BOULDER A, measured in Boulder/USA, are transmitted.
An example of the transmission
INFO 04 DEC 15 UTC KIEL K 3 3 - FORECASTS 04 DEC SUNACT QUIET MAGFIELD QUIET -
DEC R 11 11 FLUX 73 73
BOULDER A 7 7 - 03
DEC KIEL A 10 10 AR
DATE, TIME actual date, end of last 3 hours periode of "K" - measurement
KIEL K 3 hours index of the magnetic field, measured at beacon. The most
indicative of current conditions, updated every 3 h.
relative sunspot number (SSN)
solar flux at 10 cm wavelenght, measured at Penticton/Canada
averaged 24 hours index of geomagnetic activity based on the K index,
measured at Boulder/USA
averaged 24 hours index of geomagnetic activity based on the K index,
measured at beacon
SUNACT forecast of solar activity only the
following 7 expressions will be transmitted:
less than 50 % probability of C-class flares
expected, probability > 50 %
M-class flares expected
MAJOR FLARES EXPECTED X-class flares
PROTON FLARES EXPECTED
probability > 50 %
expected to increase
end of alert
forecast of the state of geomagnetic field only the following 8 expressions will be transmitted:
ACTIVE CONDS EXPECTED value
of K >= 4, A >= 20 expected
EXPECTED value of K
>= 5, A >= 30 expected
EXPECTED value of k >= 6, A
>= 50 expected
SEVERE MAGSTORM EXPECTED
value of k >= 7, A >= 100 expected
IN PROGRESS value of k >=
4, A >= 30 expected
expected to increase
>= means: greater or equal / NA = not available
30m-station: 30 watts into triangular horizontal loop
80m-station 30 watts into dipole
beacon transmits in CW-rnode in its normal loop DK0WCY BEACON, followed
by a steady carrier for some seconds. Some amateurs in Northern Germany
can remotely switch to DK0WCY BEACON ............ AURORA or DK0WCY
BEACON ...........STRONG AURORA.
Instead of the carrier a longer row of dots is transmitted.
Even without good knowledge of CW a listener can distinguish whether there is a radio aurora alert or not.
Local Measurement of Geomagnetic FieldAt
location of beacon two components of the geomagnetic field are measured
by a fluxgate magnetometer. During 3 hours periods the maximum and
minimum value of deviation from the normally quiet situation is
registred. These deviations - expressed in nanoTesla - are converted
with a conversion table to KIEL K.
At the end of each day these so
found eight figures KIEL K are used to calculate the 24 hours index
KIEL A, again with a conversion table.
BOULDER A is derived similar.
Source of R, FLUX, BOULDER A and forecasts SUNACT, MAGFIELDThese
informations are retrieved by a computer at University of Marburg
automatically via Internet from the Space Environment Center in
Boulder. Once per day (morning hours) these infos are forwarded by
telephone line to DK0WCY, also automatically. If appropriate, more
infos can be added manually in Marburg or at beacon.
explanations -Relationship between the transmitted data and propagation
excerpt of an article by G3VA in Radio Communication 9/95, Technical
The solar flare is the phenomenon which causes the most
direct disturbances in the ionosphere, representing an explosive
release of energy and particles within a relatively small region of the
Radio communication may be affected immediately
after the flare or this may not occur until one or two days after the
onset of the flare. By convention, solar flares are divided into
and X depending on the amount of X-ray energy flux associated with it.
C class flare is the least powerful
and does not immediately affect the ionosphere, although the particles
from it may disturb the ionosphere several hours later. The flux of
M class or X
class (the most powerful) flares is sufficient to disturb the
ionosphere immediately following a flare as well as producing delayed
effects from solar
I) Electromagnetic radiation from an active
flare - ultraviolet. X-ray, visible light and radio noise - all reach the Earth's
with the same delay of 8.3 minutes so that disturbances to the ionosphere from
an X flare may begin at the same time as the
flare is observed visual.
This may result in ionospheric disturbances to HF
and noise bursts on VHF and UHF.
Another (nearly) instant effect of a major solar flare is the sudden ionospheric
disturbance (SID) - also known as short wave
fade (SWF), resulting from a large increase
in the absorption of the D-layer. An SID
may block out virtually all sky-wave signals over a large part of the HF
spectrum and produce a severe black out of HF-signals
(particularly on the lower frequencies).
Since SIDs and SWFs
are caused by intense bursts of X-rays, they occur only on the daylight side of
During an intense SID, an operator may span
through many MegaHertz without hearing a signal!
II) Particle radiation, made up mostly of
protons, causes the ionosphere, and hence HF
signals, to weaken or disappear entirely on some paths and may result in
multiple delayed effects including polar cap absorption (PCA),
magnetic storms, visible auroras, and ionospheric storms.
PCA results from an increase in enhanced
ionisation of the D-region.
Magnetic storms cause a fluctuation in Earth's geomagnetic field which in turn
causes ionospheric storms which limit ionospheric propagation. Magnetic storms
may also result in auroras which may or may not be visible as far south as the
UK, Northern Germany, Norther Poland ... but provide changes in the conductivity
of the air (at height around 100 km) and result in the reflection of radio
signals up into the UHF region.
III) The energetic stream of charged
particles, mainly electrons and protons, are carried through the solar wind
towards Earth, increasing the velocity and composition of the solar wind. These
take one or two days to reach the Earth's ionosphere where they may cause
similar effects to the faster moving high energy particles noted above. At the
decline of a solar cycle and during its minimum phase coronal holes are mostly
responsible for the release of the charged particles. It may take several days
(and nights) for the ionospheric layers to return to normal. Ionospheric storm
cause the lowest usable frequency (LUF) to
rise and the maximum usable frequency (MUF)
to fall, narrowing the spread of frequencies on which communication may be
established. A band which may be wide open on undisturbed days may be devoid of
sky-wave signals during disturbed days, or received only very weakly.
Thus, from one day to the next, -the MUF may
vary by some 15% regardless of the mean sunspot level.
A primary means of defining the disturbed days is the A-index:
Potential for impact
ACTIVE CONDS EXPECTED
> or = 20
MINOR STORM EXPECTED
> or = 30
MAJOR STORM EXPECTED
> or = 50
SEVERE STORM EXPECTED
Conversion from K-index (3 hours) to the A-index
0 1 2
3 4 5
6 7 8
0 3 7
15 27 48 80
140 240 400
Note that the received K-index of today will
result only to these above shown A-index figures
of the current day, if all K-index figures
A real example:
If the K-figures would have been
3 3 1
2 1 1
2 4 and adding the
15 + 15 + 3 + 7 + 3 + 3
+ 7 + 27 = 80 gives the sum = 80.
The result (80) is then divided by 8 = 10.
So the A-figure for that day with the measured K-figures is
A = 10.
Determining Propagation from DK0WCY or WWV.
The propagation depends on the close relationship between the solar
flux, the A-index, and the K-index,
The probability is graded as follows:
(from C. Drentea, Skywave Communications, ham-radio 3/1980)
1. If solar flux less or equal 150, probability of skip is poor to good.
2. If solar flux greater 150, probability of skip is good to excellent.
If the solar flux index is as in
notes 1 and 2 and the A and
are as below, propagation probability is:
if A-index is and K-index is
Geomagnetic activity is Propagation probability is
< or =
< or =
> 7 but <15 <
> 15 but < 30 < or =
> 30 but < 50 = 4 or = 5
> or =
> or = 100
How Do The Transmitted Numbers Relate to Band Conditions? In very general terms,
here is a summary of high- and low-band conditions assuming stable solar flux, A-
20,17,15,12 and 10 meters:
On these bands, high solar flux and low A
and K index promote the best conditions over
long-distance, high latitude paths. These bands may be open around the clock on
these paths under such conditions. Low solar flux, even with low A
result in worse propagation and/or shorter openings on high-latitude paths. Of
these bands 10 meters is most sensitive to changing conditions.
160, 80, 40 and 30 meters:
These bands are relatively insensitive to solar flux, but rely heavily on low,
steady A and K-index
for good propagation on any path. When the A
and K-index are very low, polar paths and
twilight openings on these bands can provide spectacular DX at signal strengths.
When the A and K-index
are high or rapidly changing, however, D-layer
absorption increases, seriously degrading long-distance propagation. Of these
bands, 160 meters is most susceptible to degradation by changing conditions.
Keep in mind that the current solar flux, A-index
and K-index give a limited picture of
propagation conditions. To realize a trend which often take days to develop, it
is good to keep an ear on DK0WCY/WWV numbers on a regulary basis.
Various programs for predicting skywave communications are available for the
radio Amateur and the professional alike. While most programs consider only the
solar flux for determining propagation, a few use the A-index
and several other parameters to determine proper conditions.
Some names are: IONSOUND, IONCAP, MINIMUF, MINIFTZ4, PP etc.
Additional infos (in German), a logsheet document (Word for Windows 6) can be
found on :