Posts Tagged ‘fox hunt’
A different kind of Foxhunt
January 11th, 2025 | 
Author: Suitable for the urban fox
From the January-February 2025 SARC Communicator
The last few months, I've been thinking about a different way to do a Foxhunt. My vision was to have a Foxhunt available whenever you want, especially this time of year. Not everyone lives in town, and everyone's busy shopping and might not be able to dedicate an afternoon on a specific day for a group search. But what if the fox kept calling you out for a few minutes here and there, whenever you had a chance? No pressure, just try it out and see what you can find with your gear, experimenting with different antennas to get the best results. Go get that Fox!
Where to start with my build? You guessed it: Google and YouTube. The first step was to make a Fox using things I had in my toolbox. I got a Baofeng radio, Arduino UNO, batteries, a waterproof box, and a Drok buck converter. Simple enough, right?
I first searched using Miss Google and came across this: https://www.hackster.io/nfarrier/auto-keyer-for-radio-fox-hunting-e89b99 "Cool, I can do this," I thought, so I did. After putting it all together, I programmed the Arduino UNO using the Arduino software with the code from that website. I set up the CW message, and everything tested just fine. My vision was starting to come true!
 |
| My power supply was an 18 volt 5.0 Ah Lithium-Ion Battery (Makita BL1850b) feeding in the Drok Buck Converter to reduce the voltage to 7.4 Volt for the Radio and that voltage was also perfect to feed the Arduino Uno as it has a 12 volt connection with its own regulator to supply 5 volt to the board. |
I could hear it from the east and west side of town. All was good darn... a few days later I couldn't hear it anymore until I was right beside it. I took the Fox home and discovered the TX (transmit) wasn't putting out power anymore, even though the battery was still good. My Fox SX5 Mosfet transistor must have failed. It must have been spending too much time in TX mode. So, I replaced the radio and changed the transmit message, reducing the time by almost 50 percent.
There goes the fox hunt, second radio blown. How disappointed you all would be! I talked to a fellow ham about Baofeng radios. He uses them more often than me, and he showed me in the manual that the duty cycle is very small, 03/03/54 minutes (RX/TX/Standby). My fellow ham had a spare radio he wasn't using, so I bought it from him.
I did a few more programming changes to adjust the duty cycle. I also decided to add "MORE POWER!" (à la Tim Allen) So, I added a second Makita battery for a longer stay in the den.
I relocated the fox to be closer to home, just because I know I'll need to replace the batteries in a few days. For those of you in the area, I hope you all get a chance to find the Fox.
Happy Fox Hunting! 73,
~The Silver Fox VE3BQM
A video about ARDF (Radio Orienteering)
Whether you call it Amateur Radio Direction Finding (ARDF), Radio Orienteering, Fox or Bunny Hunting
The feature speaker at our May 2024 meeting was Robert Frey WA6EZV. Robert spoke on ARDF - Radio Orienteering - Fox (or Bunny) Hunting. Robert was first licensed in 1968, and his interests include DX and ARDF, as an on-foot foxhunter, for over 20 yrs. He was member of the US ARDF National Team in 2000, 02, 04, and 06 competing in China, Bulgaria, the Czech Republic and South Korea.
The presentation was recorded via Zoom so please excuse the video quality which is less than our usual presentations.
Robert Frey WA6EZVWe have documented some of our own SARC Foxhunts in years past, including this locally developed 80m fox receiver:
and
~ John VE7TI
The May-June 2023 Communicator
Here's The Communicator!
'The Communicator' digital periodical of Surrey Amateur Radio Communications is now available for view or download.
Read in over 145 countries now, with almost 14,000 downloads for the March-April issue, we bring you 130 pages of Amateur Radio news from the South West corner of Canada and elsewhere. With less fluff and ads than other Amateur Radio publications, you will find Amateur Radio related articles, projects, profiles, news, tips and how-to's for all levels of the hobby.
You can view or download it as a .PDF file:
Previous Communicator issues are at:
https://ve7sar.blogspot.com/search/label/The%20Communicator
and a full index is HERE.
As always, thank you to our contributors, and your feedback is always welcome.
The deadline for the next edition is June 15th.
If you have news or events from your club or photos, stories, projects or other items of interest from BC or elsewhere, please contact us at [email protected]
73,
John VE7TI
'The Communicator' Editor
80 Meter ARDF (Fox) Receivers
Better than ever!
Amateur Radio direction finding (ARDF), also known as Fox Hunting has become easier and more exciting using 80m. More and more kids are participating in our annual event and learning about radio. No transmitter, so no license required.
See the 'How-to' video at https://youtu.be/YK3gETNc2jU
This is a project by Surrey Amateur Radio Communications in support of the hobby
Hunting Foxes With QRP
For those of us that enjoy CW as well as QRP operating, the Winter QRP Fox Hunt nights make for an exciting combination of both interests.
The QRP Fox Hunt is an operating event during which low power (QRP) stations or "Hounds", attempt to make contact with specific QRP stations designated as "The Fox".
Spanning a twenty week period from November to April, each week sees two Fox Hunt events ... one on Tuesday evening and another on Thursday evening. The Tuesday night event sees the Hounds go hunting on 40m, while on Thursdays, the move to 80m, for an even greater challenge.
For each evening, there are two assigned 'Fox stations', usually one in the east and one in the west. The object of the hunt is for the hounds (you and I) to find and work the fox ... both foxes if you can, as bagging both is the ultimate goal. This all sounds pretty easy except for the fact that all foxes and all hounds are limited to 5W output or less, and therein lies the fun! If you have never heard a pileup of QRP stations, it is worth tuning in just to listen ... a multi-station cacophony of QRP signals, all around 559 or weaker ... it's not your typical kilowatt-laden ear crushing pileup!
The 40m foxes will be found between 7030 and 7050, while the ones on 80m will be between 3550 and 3570 kHz. Most foxes make a habit of working split, usually listening 'up 1', so once you find the pileup, the fox is easier to locate.
The hunts begin at 0200Z and run until 0329Z ... early evening here on the west coast and mid-evening out east.
Complete rules and a 'Fox Hunt Primer' may be found on the QRP Fox Hunt home page here. For discussion of the individual events and soapbox comments, join the QFox ioGroup site here or join the chat in Facebook's QFox QRP Foxhunt Group.
If you're in search of some challenging week-night operating fun, you may just find what you are looking for with the bi-weekly QRP Fox Hunts. Working both foxes is not as easy as it might sound and is an excellent test for your antenna system and of your CW operating skills. Come and join the fun this coming Tuesday ... no special hunting permits required!
Low-tech transmitter hunting
As I’ve mentioned before, KD2CHE and I belong to a local transmitter hunting group. We get together one or two times a month. One member will hide the 
box and give us a general area, which is usually a radius from a point (i.e. 2 miles from the intersection of routes 1 and 2 in Anytown, NY). We are the only ones without doppler equipment, yet we almost always find the transmitter. Here’s some pointers for those of you that enjoy a bunny hunt every now and then, but may not think you can participate without sophisticated direction-finding equipment, or for those of you with dopplers that want to refine your techniques.
First of all, when I know the area, I print a map from the computer, and draw a circle for the hunting area. Then, using either our knowledge of the area, or a combination of Google Maps, and Bing Maps, I find a large building that I can drive all the way around, as close to the center as possible. I mark the spot on the map as our starting point. KD2CHE drives, while I navigate. When the time comes to leave for the location, I load up the equipment:
- The mobile in the car, for communicating with the other hunters, an Icom IC-207H
- An older Kenwood all-mode 2 meter mobile, with an RF-gain control, attached to an OPEK micro mag mount antenna
- A smartphone with Google Maps, or a laptop with a broadband connection
- Bright flash-lite
- 1 HT set to the third harmonic of the hunt frequency, usually my Icom IC-T90A with a good antenna
- 1 HT set to the hunt frequency with the antenna off, usually my Baofeng UV3R MkII
- 1 HT set to the hunt frequency for KD2CHE to use out of the car
Once the transmitter is activated, KD2CHE drives slowly around the building at the starting point, stopping when the transmitter stops, and starting up again when it comes back (the one we use is usually 30 seconds on / 30 seconds off). I mark the points in our loop where the signal was strongest and weakest, drawing a line with an arrow to get our initial vector. Then we navigate in that direction, using Google Maps as a guide. As the signal changes I mark the observed strength on the map. When we reach the point where the signal strength goes back down, we determine the high point, and KD2CHE drives as close to perpendicular to the original route as she can.
During this process, the RF gain control on the Kenwood comes in handy. The box puts out a full 5 Watts, so as you get close to it, an un-attenuated receiver becomes useless. For the signal readings with the RF gain all the way down, I write an ‘A’ in front of the s-meter reading on the map. As the strength goes up again, we keep an eye on the 2 HTs. When we’re within 1 or 2 blocks, one or both of them will become active. The third harmonic will usually not work until you are almost on top of the transmitter, which comes in handy. This is when we start looking for a good spot. In many cases there will be a public park, or area of some sort nearby, and the rest of the hunt is done on foot with the HTs, and the flash-lite if necessary.
Body shielding will get you a direction to walk in. Hold a radio that is getting a weak signal (the IC-T90A has a fixed-level attenuator I can activate) close in to your chest and slowly turn around, and make note again of the weak and strong points in the circle. Keep in mind though that sometimes, a good hider will put the box in a location that creates reflections and ghosts. Sometimes you just need to use logic, or in the case of our last hunt, KD2CHE found the box simply by looking, while everyone else was wandering around the woods with Yagis and other fancy equipment.
Of course it helps to know the area, and to have some insight into where people like to hide things. One of our hiders frequently hides in places he discovers while hiking. Another likes to hide in very unique, and sometimes questionable places. Once or twice we’ve had to explain to the authorities what we were doing.
I’m convinced that a doppler might enhance our abilities, but I’m afraid of relying on it too much. We actually have one, but it needs some work. We’ll see.
73! Neil W2NDG
