10 GHz Beacon
Frequency: 10386.895 MHz
Location: Slieve Annora
Keeper: Gordon Curry GI6ATZ
The Beacon is housed in two separate units with the PSUs and Reference etc. in the IDU (Indoor Unit) and the Multiplication, Power amplification and Antenna in the ODU (Outdoor Unit) located on the Mast.
The Indoor Unit consists of a 4U 19” Rack mount case containing the following:
The RDDS was sourced from the UK microwave group and the PIC programmed by Brian G4NNS.
The 10 MHz ref was obtained from Hong Kong via EBay and cured all the problems that had existed using a 10 MHz xtal OCXO, The 108 MHz OCXO was built to Johns G8ACE design and was housed in an insulated diecast box.
The whole thing is one great PLL ref to the 10 MHZ source and the RDDS generates the 108 MHz signal to complete the loop. This is then feed via a 5 dB attenuator and a bias tee to put 12v up the coax to the ODU.
The IDU is fan controlled to keep it cool with 2 fans at the back using an electronic thermostat
The Outdoor Unit is housed in an ex Cellular MHA (Mast Head Amplifier) Case with a White PVC Radome covering the antenna which is mounted through the top of the housing.
The unit internally consists of a DB6NT Beacon Sender which is a 96 times multiplier and delivers 200 mW into a 20 dB attenuator to drive the MA amp to 1.2 watts and then into a coax to waveguide transition to feed a 8 slot slotted waveguide antenna.
The power arriving at the ODU is about 1 mW and 12v to drive the multiplier and the amplifier.
We would like to thank the following:
UK Microwave Group for the DB6NT unit
Sam Jewell G4DDK for the PA
If you would like to contribute to the upkeep of the GB3NGI Beacon Cluster then please click on the link below