DIRECTION FINDING

An Introduction

Agenda

• Why do we do it?• Getting Started• More developed techniques• What we do in WADARC• Rules• Summary

Why do we do it?

• It’s part of the Amateur radio hobby (sport)• It’s a chance to get outside and play radio• Encourages team building through competition• An opportunity to build equipment ( e.g attenuators )• Innovative antennas (e.g use flexible measuring tape)• An opportunity to learn about the district• Learn about signal propagation• End up at the pub!!

Getting Started (Fox)

• A rig capable of say 25 watts minimum• A decent portable power supply• Antenna and mounting pole• Good camouflage• Site capable of being heard at the start

Getting Started (Hound)

• Rig with battery power and illuminated signal level meter

• A directional antenna which should be hand held • Also be easily transportable in and out of a vehicle• A map local to the area• Ruler, pencil, rubber and protractor• A compass, preferably a sighting one.

Getting Started (organiser/fox)

• Fix start time and location• Fix operating frequency (usually 145.300MHz)• Aim for a “run time” of about 90 mins• Fix your “QSY”• Optional mobile contact number

The Fox Hunt

• Organiser at the Start point calls the fox to check point to point comms and give lead callsign of each team.

• Hunt starts at designated time• Hounds stop, take bearings, draw lines on map and

move on.• Using attenuator take bearings until fox is found then

off to the nearby QSY • Note: Be prepared for “outside” interest in the event.

Sample Configuration

• Hound kit is rig (with meter), attenuator and directional antenna e.g HB9CV

• “In car” rig on main band with mag mount• In car portable on main band with removable

antenna• Third Harmonic rig for close in work• Really deaf receiver (op amp) for well hidden foxes!

Sample Fox locations

• Under bridges• Under leaves• Under leaves in a dry ditch!• Antenna up a relay mast!• In a car park with steamed up windows!• In a car park with blow up dummy at wheel.

More Developed Techniques

• Dopplerhttp://www.eham.net/reviews/detail/1463

• Active antenna (VK3YNG)

http://www.foxhunt.com.auhttp://www.foxhunt.com.au/2m_sniffer/manual.htm

What we do in WADARC

• Only 2M and 70cm contests• Practice DF to start the series• 2M Trophy Eileen Medley• 2M Revenge Trophy G8PMF Rose Bowl• 70cm trophy to finish the series• All presented at the Construction and Presentation

evening and then engraved.• More at http://www.wadarc.com

Rules

North Wales DF events

• Run in N.Wales on a Sunday by Tom G4BKF• Two events a year. • Takes all day..break for lunch• Starts at the Clwyd Gate 10am• Two foxes each session morning and afternoon.• Teams from Birmingham and Manchester• Lunch break and end of event QSY.• Contact g4bkf@wadarc.com

Summary

• DF nights are great fun...even in the rain• Lots of opportunities for home construction• ARDF info http://www.oarc.org.uk/• C&D ARS are more than welcome to take part• We look forward to seeing you

• Goodnight and thanks for listening.