Microwave Beacons JO20KV
The beacons are in the "smallest" tower of ON4AMX - we appreciate his
assistance. We also thank the UBA for sponsoring our beaon license.
Simple and straightforward application of the DB6NT beacon transmitter,
with a 60 degrees Xtal heater. Pout 1,2W and 10 dBi antenna (slotted
waveguide). The beacon and the return loss (-38 dB at 2320 are shown)
are shown below. I calculated the beacon antenna in stock alu tubing
and frank PA4FP
It works very well as far as I can tell, with little tuning. More
antennas are available. QRG 2320,975 MHz, QRA JO20kv, 110 mASL.
3cm - Below in italics
explanation of the original beacon. My comments in red.
Nothing has changed except
reprogramming the Atmel for the current callsign ON0KUL (by ON4CDQ -
thanks) and locator. 10368,965 MHz, JO20kv, 110 mASL, ERP +/-10W.
The crew of ON4CP
In the 'proceedings' of
Roundtable 1999, Danny Orban, ON4AOD, gave a complete description of
the 10 GHz beacon of Leuven.
Right after the October
the beacon was modified. First, the instability of the frequency
reference was solved. Secondly, a new PA was added: we now have more
back off in the amplifier chain; the steps of the output power are
closer to 6 dB.
Call sign: ON4KUL
Frequency: 10.368,975 (currently ,965) GHz
waveguide, at 110
meters ASL (the antenna is on top of a 30-meter high building)
sign and locator
Transmit power: Call
sign and locator
are transmitted at a nominal power of 31,6 dBm. The output power is
then decreased to 26 / 21,2 / 15,9 / 9,3 and 2,1 dBm with 2 sec
The antenna is a slotted
with 12 slot pairs. The measured radiation pattern is presented below.
Maximum antenna gain is about 13 dBi. The minimum gain (in the dips) is
about with 10 dB less; the gain in the "sidelobes" is about 5 dB less
compared to the main direction.
If you hear the beacon,
would be appreciated. Please email it to: firstname.lastname@example.org.
It is our plan to
PSK31 modulation on the beacon. The idea behind it is that we would
like to investigate the feasibility of, and possible problems with
PSK31 modulation at 10 GHz. Please keep an eye on www.on4cp.org