1. 80m Fox hunting Receivers
Keith Witney VE7KW
Les Tocko VA7OM
Amel Krdzalic VA7KBA
23/06/2018
BCRadioSport 2016

2. Let’s Walk before we Run!
ARDF Foxhunting
Let’s Walk before we Run!
SARC meet
23/06/2018
BCRadioSport 2016

3. ARDF Foxhunting Why? Find noise or interference sources
Build some simple equipment
Get some exercise
Terrain/propagation effects
Navigation
Introduction to Amateur Radio for non- hams
23/06/2018
BCRadioSport 2016

4. ADRF Foxhunting What is it? Transmitters are hidden in a Park
Scored on number of transmitters found and the time taken.
23/06/2018
BCRadioSport 2016

5. ARDF History RDF A Brief History ARDF History
Gonimeter (directional Ant bearing)
Adcock arrays 1926
(Interconnected vertical )
Doppler Radio systems
(electronic rotation)
ARDF History
1950’s Europe as a school activity
First European Championship 1961
IARU standardized rules 1993
2004 games; 400 athletes, 29 countries 4 continents
NA mainly mobile interference location training (1970’s)
Friendship Radio Sport Games Victoria 2001
Recently added Sprint, FoxOring and Scout modes
23/06/2018
BCRadioSport 2016

6. ARDF Traditional Foxhunting
How does it work? (Traditional ARDF)
The transmitters are on for one minute each in sequence so it takes 5 minutes for a cycle.
MOE, MOI, MOS, MOH, MO5 all on the same frequency Identified by slow speed Morse (can count E, I, S, H, 5)
There is a continuous beacon (MO) at the finish for International competition on a separate frequency.
You find the transmitters by taking directional bearings, observing signal strengths and ultimately searching for the “flag”
The flag has a punch (or electronic reader) used to mark your score card.
23/06/2018
BCRadioSport 2016

7. 2m Foxhunting Propagation Challenges; Straight Line, but … Multipath
Masked by Terrain and Conductive Objects
Water Refraction
Horizontal Dipole Transmitting antenna
Easy to build antennas
Can use 2m Handhelds with attenuator and signal indicator but they have some limitations
23/06/2018
BCRadioSport 2016

8. 2m ARDF Receivers VE7KBA VE7GVS VK3YNG commercial receiver
Handheld setup (Elements folded for storage)
23/06/2018
BCRadioSport 2016

9. 80m Foxhunting Receive equipment is less bulky Effective sense antenna
Sharp null
Different but fewer propagation effects
Easier?
23/06/2018
BCRadioSport 2016

10. 80m ARDF Foxhunting ReceiverCW
Home built (loop and sense antenna) Les VA7OM
Based on DF1FO receiver board
23/06/2018
BCRadioSport 2016

11. ARDF Foxhunt Location Public Park International 10km by 10km
Local 2 km by 2 km
Eg Robert Burnaby Park
Map provided
Shows major paths and features
Topography is nice
Typically transmitters are hunted from paths.
23/06/2018
BCRadioSport 2016

12. ARDF Foxhunt
23/06/2018
BCRadioSport 2016

13. What have we learned? We have been running fox hunts for five years
There is a need for a less strenuous, simple format
Five minute cycle is frustrating for beginners
Beginners get frustrated with “simple” 2m equipment
Poor attenuators, AGC and limiting make hunting difficult
Reflections and multi-path
Beginners find 80m hunts easier
Cheap Chinese radios work but can be confusing
Tuning and attenuation need improvement
23/06/2018
BCRadioSport 2016

14. Our solution Use 80m Use mini-foxes and Sprint cycles
No multipath
Smaller receivers
Use mini-foxes and Sprint cycles
Low power, simple to set-up
Small hunt area (100m radius) so 500m by 500m
Sprint cycle is 12 seconds on every minute so you don’t have to wait too long for your next bearing
Use stable, well attenuated receivers
23/06/2018
BCRadioSport 2016

15. Implementation Les VA7OM designed a custom receiver.
23/06/2018
BCRadioSport 2016

16. Implementation
Les and Joe developed a mini-fox with the sprint cycle which could be easily deployed
23/06/2018
BCRadioSport 2016

17. Receiver/Transmitter Kits
Les Tocko with the assistance of Joe Young, Nick Massey, Dave Miller and Chris Scholefield has developed kits for the receiver and mini-transmitter
A fun project
The mini-transmitter enables practicing and testing
The kit consists of:
PCBs with surface mount devices pre-installed
All other components
PCB case with all required mounting holes as a set of PCB pieces for assembly and finishing
Assembly manual
23/06/2018
BCRadioSport 2016

18. Transmitter Kit The microfox has 4 modes DIP switch selectable:
continuous (beacon mode)
regular 1/4 minutes
fast sprint
slow sprint
Fox number and ID are preprogrammed to the processor.
23/06/2018
BCRadioSport 2016

19. Receiver Kit direct-conversion receiver with 4-pole filter
voltage-variable tuning capacitor to adjust the frequency from 3550 to 3600 kHz.
9V battery
Ferrite loop antenna for a sharp bi-directional null with switchable sense antenna for direction determination
4 step attenuator.
Total dynamic range >120dB
23/06/2018
BCRadioSport 2016

20. Receiver/Transmitter Kits
Kit assembly meeting
To further assist people with the kits, it is proposed to offer assembly meetings
Provide advice and assistance for case assembly and component “dry fit”
Provide assembly jigs
Kit testing and familiarization
Training sessions
Introduction fox hunt
23/06/2018
BCRadioSport 2016

21. Demonstration Show the kit components
Receiver and finished receiver
Transmitter and finished transmitter
Assembly manuals available for view
A mini-fox has been turned on and the receiver is connected to a speaker system
Illustrate cycle and identification
Illustrate direction finding
Null and forward/back
Illustrate attenuation
23/06/2018
BCRadioSport 2016

22. Kit costs
Note that these “introductory prices” are being provided on a non-profit cost recovery basis to provide a way for people to try the sport with decent equipment
Receiver $90
Transmitter $10
Assembly course $25
For the Receiver and Transmitter, we will require a 50% deposit. Delivery is expected to be 2 months.
To Order Contact Keith VE7KW
(604)
23/06/2018
BCRadioSport 2016

23. And Afterwards?
BCRadioSport has planned a series of events starting in May and others will be held by other groups such as SARC, BARC and ARFGS (Victoria). See for details.
The BCRadioSport events will be held in a variety of local parks, nominally every second week alternating between Sunday and Saturday and starting at 10 AM (finish at noon)
23/06/2018
BCRadioSport 2016

24. ARDF Foxhunt A typical “Hunt” This will be less formal for practice
Meet at the park 10:00
Equipment is quarantined
Transmitters have been pre-hidden or are hidden by the participants .
Transmitters are turned on remotely based on the master clock and checked for operation.
Participants are given instructions and starting time
Close to the start time given, the participant picks up map/equipment and score card and after the start proceeds to a start point not visible to other participants
23/06/2018
BCRadioSport 2016

25. ARDF Foxhunt
The hunter will take bearings on the fox which is currently transmitting, moving along a line to get bearings on all foxes. In 10 (2 for Sprint cycle) minutes a general idea of where the foxes are can be obtained. This enables a hunt strategy to be determined (optimal route)
The hunter then proceeds to the first fox in his plan, taking bearing on the other foxes as appropriate while his target is off the air. As he gets closer (signal strength and bearing closure) he will likely need to increase the attenuation. This works until you are standing over the transmit antenna!
You are not finished , you need to find the flag with it’s punch not the transmitter (The flag will be within 2-3m)
23/06/2018
BCRadioSport 2016

26. ARDF Foxhunt
This continues until you find all of the foxes or run out of time (You have to be back in the time allowed or you DNF).
Stepping it up
Once you learn how to find the foxes, you are now working against the clock
Orienteering techniques help in taking accurate bearings , minimising distance covered, understanding the terrain which might be affecting your signals
Run
23/06/2018
BCRadioSport 2016

27. ARDF Foxhunt Stepping it down Mobile Foxhunting Use teams Smaller area
Enables sharing of equipment
Non technically interested people can participate
You can have a runner/mountain goat for us who stroll
Smaller area
Mobile Foxhunting
If there is interest in mobile only Foxhunting, this can be arranged but is really something completely different as different techniques can be used.
23/06/2018
BCRadioSport 2016

28. ARDF Foxhunt What Next?
Try it! Open to all. Loaner equipment available or just observe.
Practice events a/p previous schedule
BARC annual fox hunt
SARC annual fox hunt
ARFS fox hunts (Victoria)
Collect your own gear
2m handheld (Rx only), W2HOL Directional antenna, offset attenuator
80m receiver Kit as offered above
2m receiver kit being developed
23/06/2018
BCRadioSport 2016

29. ARDF Foxhunt What Next?
Participate for Canada at International Competitions
2016 ARDF World Cup and World ARDF Championships in Albena Bulgaria August September
Region 2 ARDF Championships Killeen Texas April 6-10,
23/06/2018
BCRadioSport 2016

30. ARDF Foxhunting For more information
IARU
BC Radio Sport 2m
Antennas
Attenuators
80m
Receivers
23/06/2018
BCRadioSport 2016

31. ARDF Foxhunting For more information
BC Radio Sport
Homing In Site
ARRL and-fun-in-2010
Ultimate Automated Doppler DF System
23/06/2018
BCRadioSport 2016