Radio direction finding is used to find sources of interference to any form of wireless electronic communications, including broadcast and two-way radio, television, and telephones. It is also used to track missing or stolen cars and other property. Search and rescue workers use it to find persons in distress. Emergency Locator Transmitters in downed aircraft are tracked with RDF techniques.
When you apply these techniques and skills as activities for school related clubs, now you have a sport where the students can work at fine tuning their antennas, radios, and their skills in an applied activity.
You can have your students experience a radio direction finding activity with very little effort or costs involved. One project associate with this is the building of directional finding antennas. See the Tape Measure Yagi Beam topic page for more information on making the antennas. Once the students start using them during the hunts, they can carry on with making adaptions and fine tuning their antennas for better performance if needed during future hunts.
How does it work?
Of course there is a lot involved with the science, technology, and even amateur radio that can be added here, but we want to keep this page simple and explain the basics behind fox hunting. We will be adding more as resources and activities later on.
Here are the basics:
You have a transmitter that is set to a frequency, normally at low power and acting as a beacon.
That beacon send out a recorded signal at regular intervals, and that is called the fox. The fox is hidden at some location (preferably within 2-3 miles, but doesn't have to be... can be farther).
Your hunters, use directional antennas (preferably), to home in and find the fox.
That is the basics, and really, it is that simple. So, as you can see, based on that list we can go any direction with more information about this topic. These hunts are so exciting and fun. There is even talk about making them an Olympic sport, because in reality, you do not need an amateur radio operator license to FIND the fox. You do need one to transmit, but not to find it. What we like about it is that it takes all of the theory and principal the kids have studied for to get their license and it applies it to a more hands-on activity.
What you will need.
In order to put on a radio directional finding event, you are going to need a few things. The following is a list of the basic elements, with links where you can find more information. Directional finding can be a whole other website, and in fact check out the Related Resources at the end of this page, there is a link to a website that is entirely dedicated to the topic.
ANTENNAS: The students (or participants) are going to need directional antennas. Check out our topic The Tape Measure Yagi Beam, we used these antennas during our hunt.
THE FOX: The fox is a transmitter that is configured to be your beacon. There are several ways that you can do this with various pieces of equipment. We used a modified BaoFeng radio with an arduino board to transmit out the beacon code. Unfortunately, at the time of writing this, the website with the plans to our fox is currently down. We will keep checking for it to come back up and then come back and update this page, but until then, you can purchase a fox at: Byonics' Website or search the Internet for more DIY plans.
Rescue the Easter Bunny - Ham Radio Fox Hunting for Beginners
We found the following video by Todd Harrison that explains the entire process and beginner's tips for a fox hunt, especially for kids. This is a great video and explains everything.
For those not interested in the ham details you might want to skip to the last 3 minutes started at time 33:00. In the last 3 minutes of the video 4 young kids go out to rescue the poor lost Easter Bunny and his basket of candy. The Easter bunny is wearing a radio transmitter so this fox hunt becomes an Easter Sunday bunny hunt. The boys did great and had no problem learning to use a ham radio and directional antenna to locate the lost bunny.
Homing In Website A complete website dedicated to the Art and Science of Radio Direction Finding.ARR Radio Direction Finding Information about radio direction finding on the ARRL website.Micro-Fox T-Hunt Transmitters Byonics website has various electronic projects for amateur radio. You can purchase your fox or T-hunt transmitters already built if you don't want to build your own.
Do you have questions or more information to share?