Welcome to Day 1 of the Defcon 26 Ham Radio Fox Hunting Contest!
This contest is simple, and is designed to teach you the basics of VHF transmitter direction finding and hunting.
To participate, you will need a radio or a scanner that can receive signals in the 2m Amateur Radio band (aka 14X.XXX MHz).
Today's goal is to locate 3 hidden radio transmitters (the "foxes") that are hidden in the contest area.
Today is not intended to be difficult, and you should have no problems finding all three.
We will provide hints if you are totally stuck.
What You're Looking For:
This contest uses the WB6EYV MicroHunt transmitter, a purpose-built transmitter designed for fox hunting and ADRF. These units transmit at 50mW, and they will burst a short message in CW (aka Morse Code) approximately every 15 seconds. Each of the 3 transmitters will use a different frequency in order to not make finding them harder.
The unit itself looks like this:
The device when you locate it will be in a metal casing like this:
When you locate the transmitter, please be kind to other participants (and to the Contest), and don't remove it, switch it off, or mess with it.
There's no prize for first place or shortest hunt - everyone who participates and finds the transmitters will receive a small commemorative trophy!
What Frequencies Should I Be Tuning To?
The 3 foxes will be transmitting on the commonly-accepted VHF fox hunting/direction finding frequencies:
- Transmitter 1: Transmits "MOE" in Morse Code (plus my callsign) on 146.565 MHz
- Transmitter 2: Transmits "MOI" in Morse Code (plus my callsign) on 146.430 MHz
- Transmitter 3: Transmist "MOS" in Morse Code (plus my callsign) on 145.565 MHz
How Do I Hunt With a Regular HT/Radio?
So here's the fun part - you don't need fancy antennas or complex/expensive gear to find many foxes. All you need is you, a radio, and patience!
The technique you should use (if you're new to this - if you're not, why are you still reading? Go find the foxes!) is called Body Fade. In a nutshell, you are using your body itself to block as much signal as possible in order to give you a vector to search towards. Hold your radio close to your chest while slowly turning in a circle when you hear the transmission from the fox.
You're looking for the direction where your body blocks most or all of the signal (the "null" or "signal null"). Some radios will have a signal strength meter that you can watch, or you can adjust the Squelch on your radio while listening until the transmission no longer breaks the squelch. What does that mean? Well, that means the signal should be directly behind you - so do a 180 turn and walk for a bit.
After walking for a short moment, repeat the body fade technique to ensure you're still heading in the right direction. The signal should increase in strength. Note that the null you've created with your body is quite shallow. It can sometimes pick up signal reflections off of RF-reflective surfaces. If you are not getting a good null, reflections might be an issue: just move to a "clearer" location and try again.
When you've reached a place where the signal is so strong that you can't find a null, tune your radio 5 or 10 KHz off frequency. This should help find a null, but this depends on the quality of the bandpass filter on your radio. to put the signal into the skirts of the receiver's IF passband. If your hand-held is dual-band (144/440 MHz), try tuning to the much weaker third harmonic of the signal in the 70 cm band while performing the body fade technique.
Disconnecting the radio's antenna will knock down the signal even more. If you hear the signal with the antenna off? Look around you, you're probably within a few feet of the fox.
Now That I've Found Them...
Congrats, you're now a Fox Hunter! No DCFurs were harmed in this hunt!
The contest table will be staffed from 10:00AM-11:30AM and 2:00-3:30PM Friday. You can come by to discuss your hunt, and you can collect your trophy.
On Day 2... the foxes will get substantially more difficult to find... So come back to the website Saturday morning for a more difficult challenge.
And have fun!
DAY 2 CONTENT BELOW JUST FOR POSTERITY
Welcome to Day 2 - With Bad News To Share
Thank you to everyone who joined in on Friday! Day 1 was a tremendous success with over 40 people/teams successfully finding the hidden transmitters in the contest area.
Today's hunt is cancelled: the hidden transmitters have gone missing.
I do not know if they were found by someone at Caesar's, or someone stole them - I am trying to find out from Caesar's if they have them.
If someone did steal them, I am offering a $200 reward for their return, as these were not inexpensive devices. :(
No questions asked, I'd just like them returned.
Thanks to everyone who had a great time Friday! If they return, we'll do it again today.
For those who participated, you can reach me here: