First fox hunt

[jeepinjeepin]

I went on my first fox hunt today. I learned a few things. Bring a map and compass. I had my compass but couldn't find a map beforehand. Bring everything you have that can receive the signal. I used my mobile part of the time to check signal strength which meant I might have been missing out on hints or chatter. A second HT and a mag mount would have helped out. Don't rush. I drove 31.7 miles to reach a fox about 6 miles away because I was driving around in circles where I thought it was...because while I had a compass I had no map to draw bearings on. Which brings me back to; bring a map.

Edit: Another problem I had is that my Baofeng does not have an S-Meter on it to help with determining direction. I was just sweeping and aiming for the center of the sweep. I need to find a cheap HT or build a receiver for next time that has a method of indicating signal strength.

 

[vagrant]

While a receiver with a meter is helpful, you can fox hunt without it.

You may need a directional yagi or log periodic at the starting point to even hear the fox, but usually after that an HT performs well using only body fade. Basically, hold the HT pressed against the front of your stomach/chest and turn in a circle listening to the audio for the high point. As you get closer to the fox, engage the attenuator, switch to a low performance antenna, or both. (Make sure you are away from the vehicle when you perform the body fade.)

I fox hunt regularly and I have seen a wide myriad of contraptions. To each his own, but the body fade technique is a low cost and working solution. I have used a Baofeng myself doing this many times. The key issue here is the audio and listening to the signal. If you have trouble discerning the clarity of the audio, even with an earplug/headphones, then you should find a solution that has a meter.

An omni-directional antenna on your vehicle is not the best way to fox hunt.

 

[jeepinjeepin]

Yeah, I finally figured the omni wasn't working. I should have realized that to begin with. I do have a 2 meter tape measure yagi. I'm kinda looking for a multi element 439 mhz yagi to listen to the harmonic when I get closer.

 

[vagrant]

Do not worry about the harmonics bit, just tune your receiver slightly off frequency and listen.

Set your receiver to step at its lowest setting, then press the up or down arrow on the Baofeng to do this. Always zero back to the hunt frequency after moving, or not, then adjust it. Lather, rinse, repeat.

Combining that with attenuation (does the Baofeng do that?) and body fade works.

What is nice about T-hunting, is a person does not need to be a licensed operator to hunt. A portable scanner will work just as well using the methods above.

 

[jeepinjeepin]

By attenuation do you mean squelch? If so, kinda. 0 is off. 1-9 are on, but not different levels. The newer Baofengs are supposed to have levels of squelch.

 

[vagrant]

I leave the squelch turned off "0", so I can hear the signal difference as I spin around. By attenuation I do mean attenuation and it does not appear that the Baofeng has that. Still, you can use the slightly off freq method as the signal becomes stronger. A fox hunt is about testing new things and having fun. Those tape measure yagi antennas work and will assist you with getting a bearing. While I have an Elk antenna, I may build a measuring tape log periodic as an exercise and enjoy VHF/UHF and not worry about blazing a trail with it. Thank you for your thread. I believe I will make one during the holiday break here.

 

[wska999]

Using the squelch process, I found a jammer in 10 minutes. I was also teaching a new operator how to track signals. Found many in the Chicago area with this method. Used an FS meter in some cases.
It's funny when you track to someone's home.

 

[jeepinjeepin]

This is the design I started with. http://theleggios.net/wb2hol/projects/rdf/tape_bm.htm

Here is another. http://ccars.org/Projects/TapeYagi/

I ended up having to trim the elements and beam dimensions from the first site. I remember removing 1" between DE/Director and DE/Reflector. I'll post final measurements later.

 

[SpectreOZ]

It's funny when you track to someone's home.

People get their backs up over such activity so funny is not the description I would use, a field strength meter with variable gain control will allow you to determine with 100% accuracy who the no-good-nic is or alternatively where the hidden transmitter has been secreted...

 

[radioman2001]

I've used UHF Yagi to track interference on 160 mhz. In general it's a good idea to get some what close and switch to the UHF Yagi as it's not tuned to freq, so you do get some attenuation of signal. I've tracked interference right down to a satellite LNA,computer,cash register,clock radio and fax machine.

 

[teufler]

When you get in close, say 500 to 750 feet, if you don't have a step attenuator, and the hunt is on vhf, take the vhf freq, times 3, and track that signal. you are tracking on the 3 harmonic. You don't have to go to a uhf antenna, the tape measure works .m You can body fade on the third harmonic also. The best fox hunt I ever saw was when the fox put a transmitter in a baby carriage. The push to talk, was the hand brake on the carriage. The fox was at the park waiting for a bus. The signal was strong so we all started visually looking and nothing was visable. We had walkers in the crowd, with beam antennas, people driving by. They would go round the block then drive around again. The other fox hunt that was pretty good, the fox had a 2 meter ht and a coat hanger with tin foil stripes hand down from the hanger. The radio was in the middle of the coat hanger and the tin foil. Radio was out in the open in a trees. wind would blow the foil around as the radio would transmit. Sometimes the signal was strong and sometimes weak. All depended on if the foil was blocking the radiated pattern of the antenna or not. The power indications on receivers jumped all over the scale.

 

[KE5MC]

One feature in the tape measure design often overlooked is the deep null on the backside of the beam. Once you are near the fox switch from looking for a peak to looking for a dip.

Mike

This is the design I started with. http://theleggios.net/wb2hol/projects/rdf/tape_bm.htm

Here is another. Tape Measure Yagi Antenna Construction

I ended up having to trim the elements and beam dimensions from the first site. I remember removing 1" between DE/Director and DE/Reflector. I'll post final measurements later.