Put your directional finding skills to use and join us every weekend for our RWK Foxhunt! Foxes are placed somewhere in the city of Richardson every Saturday morning. The fox chirps on 144.5MHz every few minutes. There also may be a fox on a UHF frequency.
The foxes are usually active from Saturday morning until Sunday afternoon (or the battery gives out). Once you find the fox, just use your smart phone and shoot the QR code on the front of the Fox with your camera to go to the online fox hunt log. If you can’t get the QR code to work, type in the coded URL just under the code from any phone or computer.
Please join the K5RWK groups.io discussion group for up to the minute news about Fox deployments and events and winners!
What Is Foxhunting?
Foxhunting (hidden transmitter hunting) participants attempt to find a hidden transmitter (the “fox”), using handheld or mobile directional antennas within a designated area. As a minimum, you will need a mobile or portable 2M radio and usually a directional antenna, although some hunters use multiple radios and specialized DF antennas. You can work alone or in teams to find the fox.
While foxhunting is fun on its own, it’s actually good practice for hams to be able to find malicious or unintended interference from other radio sources. It’s important to have a good team of trained “hunters” to nail down interference sources, and foxhunting is great training.
- Know your radio – get a feel for how your radio sounds for close, strong and weak signals. This will give you an initial indication of how far you are from the fox.
- Use a directional antenna – You should have a portable “DF” antenna that you can point while listening to the fox. You should be able to narrow down the general direction of the fox from your location.
- Triangulate – Take readings from multiple locations and see if your readings converge to a smaller area. This will lead you to the next location closer to the fox.
- Weak is Strong – While most small yagi antennas have a fairly wide (30-40 degree) main lobe, sometimes the nulls off the back can be much sharper. Search for the null and the fox will be in the opposite direction.
- Attenuate – When you get close to the fox, it will be harder to listen for signal changes from your antenna. Use an attenuator to drop the signal to a lower level. Your body also makes an excellent attenuator at VHF/UHF – by holding your HT close to your chest and rotating you can sometimes find a null.
- Beware of reflections – Just like light off a mirror, RF can reflect off of large, flat surfaces. These reflections can seem like valid sources but they will only make you mad (hint: sometimes the foxmasters do this on purpose!).
- Shift Frequencies – Especially on FM, a shift of 5kHz or 10kHz up or down from the fox frequency, will weaken the signal enough to get a better direction reading.
- Use Harmonics – No transmitter is perfect, and some are outright dirty when you get close. Listen for the third harmonic of the signal (third harmonic of 144.5MHz is 433.5MHz) – if you hear the third harmonic, you are very close!
Helpful Presentations and Materials
The RWK sponsors a monthly prize for one licensed ham who finds the fox every calendar month.
Fox hunt prize rules:
- You must be a licensed amateur to enter.
- All licensed amateurs in your party/team who find the fox may enter.
- Entrants must provide a separate log entry with name, call sign and a contact info on the foxhunt log.
- Each entrant is entitled to one entry per fox found each weekend (Eg. two foxes found = two entries max).
- One prize will be awarded for each calendar month.
- The winner will be randomly selected publicly at the General Meeting in the following month.