GM4CXM and GM3WOJ Personal 10 GHz Beacons

Alan Dimmick GM0USI andBrian W Flynn GM8BJF

Personal Microwave Beacons

• Beacons are a good way of generating interest in microwaves – signals there most of the time!

• Also keep the bands occupied!• Bit of a nuisance at your home QTH if active

yourself!

GM4CXM/B

Spots on beaconspot.eu

GM3WOJ/B

Origins of the Beacon Project

• Dawned on me that some of the Cairngorm peaks are LoS from both Edinburgh and Lowlands and East Coast of Ross and Cromarty

• Planned a QSO using “Grampian scatter” from Chris Tran’s QTH

• Chris offered to Host a beacon if I provided it.

Locations and Scatter Plot

Path Profile

Block Diagram of Hardware

Hardware

Installed on Tower

View South to Ben Macdui

Receiver Monitor Dish in IO85JV

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Dish and Receiver

The Receiver (Not Pretty!)

Live Audio

• http://gm8bjf.no-ip.org:5700• http://192.168.0.7:8000

Doppler “Tail”

Beacon Specification

• Callsign GM3WOJ• Location IO77WS62• Mode(s) JT4G + FSK• Frequency 10368.400 MHz• Reference OCXO (Usually within 500Hz of nominal carrier

frequency)• Power 700 mW• Antenna 35 cm off-set parabola (Ex BSB dish)• Beamwidth 7 degrees• Beam heading ~165 degrees• JT4G timing GPS

Acknowledgements

• Chris Towns G8BKE – Donation of PA• Susan Kivlin – Soldering of LMX2541 to PCB• David Anderson GM6BIG – Donation of OCXO• Chris Tran GM3WOJ – The location.• Andy Talbot G4JNT - for doing the hard work

sorting out the JT4G coding.