Technical data:
Fq
10368.810 MHz
Est freq drift < 207 Hz per year
Pout
37 dBm (5 W) into flexible waveguide
Keying A1A
( 3x "SK6YH/B" + 1x "SK6YH/B JO57TQ"... carrier on for approx 40 s)
Key up/down > 80 dB
Antenna 600 mm
DISH, approx 33 dB
Estimated EiRP 70 dBm (10 kW)
FREQUENCY ACCURACY
Beacon frequency is locked to a 5 MHz OCVCXO. Specification for
the oven is +/- 2E-8 overall frequency stability over 1 year. This
gives
that the beacon frequency should not drift more than 207 Hz per year.
Frequency
has been adjusted to nominal 10368.810000 Hz in july 2002.
Technical description
VCXO
The VCXO is an emitter harmonic
oscillator with a capacitance diode from the xtal to ground. A PMB2306T
from Infineon (Siemens)is used in the PLL-circuit. The PLL dividers are
loaded from a PIC (16F84) at power on which then (the PIC) goes into
beacon
mode and generates the keying of the beacon. The output pwr from the
VCXO
box is approx 10 dBm at 108.0083333 MHz.
KEYING AND MULTIPLIER UNIT
The 108.008333 MHz signal is fed into the keying unit which
consists of two GaAs SPDT switches with the unconected one port
terminated in 50 ohm. This configuration gives the advantage that when
keying is off - both the input to the multiplier chain and the output
from the VCXO is terminated in a 50 ohm load minimizing the frequency
pulling on the oscillator.
BEACON MULTIPLIER MKU10 by DB6NT opt01
The beacon multiplier by DB6NT has been slightly modified because it
started to self oscillate 50 MHz below the beacon frequency when the
input signal was in the off state. Some additional decoupling
capacitors were needed.
POWER AMPLIFIER MT10Z5W by DL2AM
The signal from the beacon multiplier is fed into the DL2AM power
amplifier. The amplifier consisits of a MGF2415 (Mitsubishi) driver
stage and a TIM1011-4 (Toshiba) final stage.
DC/DC - POWER SUPPLY
All beacon parts are fed with +12 VDC. The power amplifier has a 2A
fuse and the voltage is filtered by 33uH/100uF. The other parts are
fused by 1.6 A fuse and three separate filters (33uH/100uF). The three
separate voltages are fed to the Ref osc, multiplier and
VCXO/PLL/Keying unit.
The 12V voltage is created by a DC/DC module from Lucent. This module
can be fed with any voltage between 36 - 75 V. The module is fed with
48 VDC from a transformer, a simple rectifier and filter capacitors.
ANTENNA
The beacon antenna is a 600 mm dish which
approximately have 33 dB of gain.
Inside SK6YH/B, 10368.810 MHz
SK6YH/B outside
Changed 2004-10-26 by SM6PGP