The actual beacon
The actual beacon
The transmitter
The transmitter
The power supplies
The power supplies

DRIVER comes from KUHNE Eletronic with reference MKU 13 BAKE. It comprises three stages. The first one is a quartz oscillator at 108 MHz, stabilized at 40 C (TCXO). The signal is then multiplied by 4 and then by 3 to obtain the required frequency. The final stage is an amplifier delivering an output power of 1W. It can be modulated in CW mode in either A1 (accepted solution) or F1 thanks to the CW generator designed by ON6YH.

The Power Amplifier made by Eisch-Kafka-Electronic is designed around the Mitsubishi RF power module M57762. The gain is 13 dB under 12.5V and the output power is, in our case, limited to 10W. We express our gratitude to ON7PC for giving it as a gift.

The Power Supplies are switched mode type to get the maximum efficiciency. The manufacturer is MEAN WELL and the references are RS-25-12 and S-60-12.

The three antennas are slots waveguide type. The realization was made according to the HSLA software developed by DK3BA and DH6SBN available on Internet. Our antennas are 6 slots design.
A first antenna has been made by ON5PT on a classical milling machine. The next two have been realized by ON4DJP  on a homemade CNC milling machine!

The 22 meter coaxial cable is a 0.5" HiFlex type.

The 3 way power divider (or splitter) spreads the power equally across the 3 antennas. It consists of a quarter of a wave length with a characteristic impedance equal to the square root of (50 x 50/3) = 28.87 Ohm. Practically, this device was made off a square aluminium tube of 21 mm internal side and a copper round tube of 15 mm diameter. The characteristic impedance resulting from this geometry is equal to 29.98 Ohm. This is not so bad with standard harware equipment...
Please, send your listening report to:
The antenna consists of 3 slots antennas fixed on each side of the tower.
The installation of antennas, ON5CG doing the job... ON5CG going into the wind! The 3 antennas fixed...
The installation of antennas, ON5CG doing the job... ON5CG going into the wind! The 3 antennas fixed...
Schéma Bkoc
The power divider "1 to 3"

Beacon 23 cm
Call sign
Tx (driver)
Nominal Frequency
1296.860 MHz
Output Power
10 W
6 slots, 12 dB
3 antennas, 120 shifted
19 m  above ground
244 m ASL
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Final milling of the antenna on a home made machine (ON4DJP)
Mitsubishi M57762
Alim S-60-12