I2MOV - Radioamatore

DK0WCY - Aurora Beacon



A 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 band.
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.
Amateurs 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 (summer -1)
30m: 10144 kHz  .  Time of transmission  24 hours
The "normal" loop of transmission is:
DK0WCY BEACON _____________ (followed by a carrier).
In case of radio aurora alert:
DK0WCY BEACON ................ AURORA (dots).
If a very strong radio aurora event is observed:
DK0WCY BEACON ................ STRONG AURORA (dots).
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 is:
03 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.
R                      relative sunspot number (SSN)
FLUX              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
KIEL A             
   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:
                      QUIET                                        less than 50 % probability of C-class flares
                      ERUPTIVE                                  C-class flares expected, probability > 50 %
                      ACTIVE                                      M-class flares expected
                      MAJOR FLARES EXPECTED          X-class flares expected
                      PROTON FLARES EXPECTED        probability > 50 %
                      WARNING CONDITION                 activity levels expected to increase
                      NIL                                            end of alert period
MAGFIELD       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
                      MINOR STORM EXPECTED             value of K >= 5, A >= 30  expected
                      MAJOR STORM EXPECTED            value of k >= 6, A >= 50  expected
                      SEVERE MAGSTORM EXPECTED     value of k >= 7, A >= 100 expected
                      MAGSTORM IN PROGRESS            value of k >= 4, A >= 30 expected
                      WARNING CONDITION                   activity levels expected to increase
                      NIL                                              end of warning period
>= means: greater or equal   /  NA  = not available
30m-station:     30 watts into triangular horizontal loop
80m-station      30 watts into dipole
Additional infos:The 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.
Some explanations -Relationship between the transmitted data and propagation excerpt of an article by G3VA in Radio Communication 9/95, Technical Topics)
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 solar atmosphere.
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 three classes:
C, M and X depending on the amount of X-ray energy flux associated with it.
A 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 radiation.
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 the globe.
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:
Level                                          A-index               Potential for impact QUIET                                         0 - 19                    Low
ACTIVE CONDS EXPECTED             > or = 20               Moderate
MINOR STORM EXPECTED             > or = 30               Moderate
MAJOR STORM EXPECTED            > or = 50                High
SEVERE STORM EXPECTED            > 100                    Very high
Conversion from K-index (3 hours) to the A-index (24 hours):
K-index    0     1     2     3     4      5      6      7       8       9
A-index    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 are equal.   
A real example:
If the K-figures would have been
3       3       1      2     1      1      2      4     and adding the equivalent A-numbers
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, as shown.
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 K-index are as below, propagation probability is:
if A-index is     and K-index is      Geomagnetic activity is    Propagation probability is < or = 7              < or = 2               quiet                                  excellent
>   7 but <15       < or = 3               unsettled                            good
> 15 but < 30      < or = 4               active                                 fair
> 30 but < 50      = 4 or = 5            stormy (minor)                    poor
> or = 50            > 6                      stormy (major)                    very poor
> or = 100          > 7                      stormy (severe)                   black out
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- and K-index values:
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 and K-index, 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.   
Additional infos (in German), a logsheet document (Word for Windows 6) can be found on :



Ultimo aggiornamento: 09-01-16