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Transmitter Hunting Equipment

I would like to help fellow T-Hunters with equipment idea's and recommendations. If you have anything you would like to contribute, please email me at [email protected].

My list of recommended T-Hunting equipment
(All can be purchased, over the counter and ready to go)

Most Important Tools.
1) Icom IC-R3 receiver with four built-in attenuators (totaling 40db). This receiver will provide three uses.
    a) Initial bearing receiver connected to your beam. You can also body-fade with this receiver.
    b) U-R-Here receiver. Lets you know how close you are to the Fox, in four steps, from 4-miles to 250 ft.
    c) Close-in receiver connected to your beam. You can also body-fade close-in with this receiver.

2) Arrow Beam. 4-element beam on 2-meters, best for initial bearings. Good gain and narrow beam.
    The satellite beam, 3-elements on 2-meters & 7-elements 70-cm  also works well but, is best suited for
    close-in work. Broad 2-meter beam but, very high gain and narrow 70cm signal on the 70cm beam.
    By the way, I close-in hunt the Fox transmitter by listening to the very attenuated 3rd harmonic
    frequency on the 70cm side of the beam. I can usually get within 10 feet of the transmitter.

3) Arrow Attenuator. Usually necessary to drop the signal strength of the Fox transmitter to tolerable level.
    About 1/2 scale on the receivers signal strength meter. Up-to 75db of attenuation and when combined
    with the IC-R3 receiver, you have up-to 115db. (Warning: Do not transmit through any ATTENUATOR).

4) Compass. Magnetic is best, I've tried digital and prefer a non-battery operated compass.

4) Protractor. The one's used by mariners to plot their course. I purchased mine from West Marine.

5) Maps. One continuous map of the entire 'hunt' area. 'AAA' auto club maps seem to work best. Have your
    maps laminated in plastic. You can write on them with a felt-tip pen and erase the markings with
    Isopropyl Alcohol.

Then Add
6) Optoelectronics Scout-40, frequency counter directs you to the fox from about 200 feet to under 1 inch.
    This is a really great close-in tool. I use the Scout-40 with my Arrow beam and can get within 1 inch of
    the transmitting antenna. Using the Scout-40 without any antenna, I can determine which blade of
    grass is radiating.

8) Flashlight. Most hunts end in the dark. I use a 3-LED 'PETZL' head-band light (keeps my hands free), made
    by C-Crain. The 3-AA alkaline batteries last over 30 hours and continues to give off usable light for
    another 100 hours. The bulbs are unbreakable and lasts for 1000's of hours.

9) AHHA Microfinder Doppler. Great for getting to the fox without stopping for more bearing. If your serious
    about transmitter hunting, this device will make hunting fun and easy.

10) Garmin StreetPilot-III. Great street level mapping. Plot shortest route to the fox and never get lost.
      Saves you mileage. I tend to plot a straight line 5 mile bearing on the streetPilot-III, using a bearing
      from my Doppler and then ask the StreetPilot-III to automatically figure the shortest route to that point.
      It really helps when your in a strange location and can't figure out how to get there from here.

11) Mobile amateur radio. Dual band, so you can listen to the fox and talk to the other hunters
      simultaneously. It really helps as a U-R-getting-close radio.

(I have a lot more gadgets but, the above is what I use on almost all my hunts)


Larger image of the SuperDF and antenna.
Larger image of the SuperDF unit.

Reactivating my Super DF.
TDOA (time difference of arrival).

This direction finding tool is the single most versatile of all the equipment mentioned below. With this one tool, you can;
1) Obtain your initial bearing from the start point.
2) Hunt Vertical or Horizontal signals by rotating the antenna.
3) Hunt while mobile with the antenna mounted outside the car.
4) Hunt Close-In, within a foot of the fox transmitter.

Multi-path is this tools single biggest enemy.
1) Incomplete nulling of the RDF tone, you have multi-path.
2) Harsh or raspy RDF tone, you have multi-path.

Reduce the error caused by multi-path.
1) Take several bearings close together, about 1 foot apart.
2) Note the two most extreme (divergent) bearings.
3) The best bearing is the middle of the two extremes.

Jim Sakane - KD6DX

Arrow Satellite Beam. 3-element 2-meter and 7-element 70cm.
I have found this duel band beam to be the most versatile transmitter hunting beam I have owned. The three element 2-meter portion is a compromise. I personally like to use four elements for my initial bearing because of the extra sensitivity however, the three elements on 2-meters makes it a lot more compact and easier to maneuver when walking.

The 7-element 70cm portion really won me over. Using a truly duel band transceiver (Standard C568A), I leave the left VFO on the fox frequency and the right VFO on the third harmonic. I can hear a 50mw transmitter clear across a large park on the VHF side and then sniff out the fox, within a few feet on the UHF side without changing radio's or beams. I still have to use my Scout-40 (frequency counter) and attenuator for an even closer, pin point location (under one inch).


Arrow 146-4/3 a 4-element two-meter beam, convertible to very portable 3-element, hiking beam.

The four element beam is your best bet for an initial bearing. You can pull out weak signals (sometimes they are very weak) and the directional lobe is narrow, giving you the confidence that you are headed in the right direction.
Larger image of this photo.
Turn up the attenuator and your squelch, until your receiver only receives the fox for a short 'blip' while you swing the beam. This will give you the most accurate direction. Using the Icom R3 in DF mode is much easier. Just look at the Graphic Display, and stop when you see the peak.


Icom IC-R3
This Icom receiver comes with a Direction Finding mode. I have found this function very helpful. Since the display graphs signal strength, you can quickly determine the direction of peak signal meter readings. Body-fading is now so easy.

You can use the R3 as a U-R-Here radio too. With four built-in attenuation levels, I am able to step my distance to the fox, from two miles away, down to 250 feet from the transmitter. Any other U-R-Here radio only gives you one indication and that is usually 1/2 mile.

Click here for my report and conclusions.

The receiver for your initial bearing beam must be sensitive and have excellent selectivity. I have used a LOT of radios and found that "STANDARD RADIO handhelds" have the best immunity to adjacent channel and frequency mixing interference however, Standard is no longer in business. The Icom IC-R3 is acceptable for your initial bearing and is the best U-R-Here radio I've ever used.


Attenuator. This resistor filled switch box is essential in cutting down a strong signal strength getting into your receiver. It allows you to read your S-Meter at half scale for the strongest signal in a given direction.

Pretty cheap and works really well.
Do not transmit through any ATTENUATOR. Disable the PTT.

Compass. I have found a good magnetic compass, like the one pictured, is a must. I own and have used many digital, electronic, compass's and found the batteries dead or needed recalibration when I needed it. Make sure your compass is liquid filled.
Protractor. A good plotting protractor is also a important. Plotting your initial bearing on a large map of the hunt area must be accurate and fast.

Close-In, Scout-40 Frequency Counter.
Using a Frequency Counter (the Scout-40 has a signal strength meter), with your initial bearing beam and attenuator, you can sniff out the radiating element of a fox transmitter to within less than one inch.

The Scout-40 has a maximum range of about 500 feet (typically 250 feet). If you use the Icom-R3 will your beam, you can get you within 250 feet of the fox before it saturates. Switch to the Scout-40 with your beam and sniff out the fox to within less than one inch.

+ Flashlight. Most hunts end in the dark. You must see where your going, your equipment and the hidden transmitter. I use C-Crain's 3-LED 'PETZL' head-band light. A hands-free light is very useful.


The Garmin StreetPilot (satellite, global positioning system), during the hunt, helps me predict my course of action and and avoid dead-end streets.

I now use the Garmin StreetPilot-III, for auto-routing the shortest distance between two points on street level maps.
It really helps when your in a strange location and can't figure out how to get there from here.

Larger image of the Doppler mounted in my Jeep.
Larger image of the 8 element doppler antenna.

Using a Doppler like the "AHHA MicroFinder" improved my transmitter hunting and made hunting a lot more fun. Watching the display pointing along my initial bearing is a big help in building confidence. The Doppler really shines when you are close-in, giving you the edge when winding around short City streets, trying to home-in on the Fox.

The "AHHA MicroFinder" can display your desired direction in three modes, raw non-filtered and two digitally filtered modes. Filter-1 can reduce the flutter of a general direction by 30% (not user adjustable). Filter-2 can reduce the flutter to a single LED (user adjustable).

               Operational Parameters for Filter-2.
QQ: indicates the required good signal quality before a sample signal can be placed in the queue. (0-9)
MISS: indicates how many signal samples may be missed before the queue is emptied and has to start acquiring samples again.
DEPTH: indicates how many good samples must be in the queue before a signal is considered "acquired" and is displayed. (1-100)

Factory default was set to display a direction, if it can acquired 12 good signal samples with a signal 'Quality' of 2 or better but, will throw out all the good samples and start the acquiring process all over again if it receives 10 bad signals at anytime.

This setting was too accurate. It only started to point when your really close to the Fox.

Experimenting with the Parameters of Filter-2 has lead me to leave the 'QUALITY' set to '2', the 'MISS' parameter to 10 but, reduced the 'DEPTH' to 10 (2 / 10 / 10).

I have to tell you, this 'Digital Signal Filter" really worked. No more ambiguous, multiple, spinning LED's pointing somewhat in the direction of the Fox. What I saw was only one LED pointing in the direction of the Fox. When acquisition of the signal was lost, the Doppler continued to point in the last known direction of the transmitter. If you pass through a 'Hot' spot of good signals, the Doppler locked onto and only displayed the direction of the good signal. I haven't noticed any loss of accuracy. However, I did notice my Doppler displaying a very regular and consistent direction to a hidden transmitter.

I'm going to play around with other setting like, QUALITY 4, MISS 5 and DEPTH 5. Maybe QUALITY 2, MISS 7 and DEPTH 7. How about QUALITY 1, MISS 10, DEPTH 20 ?

I changed the Doppler's 'Filter' parameter on the Feb.2,2002 hunt to Quality 2, Miss 9 and Depth 9 (2 / 9 / 9). This seems to be the lowest (least accurate) I want to go. The Doppler seems to be very responsive with this setting, giving me reasonable accuracy in pointing to the transmitter. The jammer transmitter gave me a little trouble only because the Fox chose to transmit short (2 to 3 seconds) bursts at 5 minute intervals. Waiting for the transmissions, I was stationary. When I started rolling to average the signal through the filter, the transmission stopped. I would recommend using the Doppler in non-filter mode on jammer hunts like this.

Like on the Feb. 2, 2002 hunt, I left my QFIL set to (2 / 9 / 9). On this hunt, Feb 16, 2002, the setting worked out perfectly. I'm leaving it set to the almost perfect (QFIL 2 / 9 / 9). The AHHA Doppler pointed most of the time and correctly to the Foxes. I only noticed a few incorrect directions and only for an instant. The Doppler corrected itself very quickly. I think we have have winner here.

By the way, I have version 1 of the AHHA MicroFinder. Version 2 has even more features.

standar radio c5900da

Mobile Radio, U-R-Here on the 3rd Harmonic

I set one side of my mobile radio to receive the 3rd harmonic of the Fox. When this radio begins to receive a signal, I'm probably within 1300 feet and when it is full scale, I'm 300 feet from the Fox.


Web page, detailing the VX1 setup.

U-R-Here, 1st 'IF' (your close) Radio

Next, I setup my U-R-Here radio, a Yaesu VX-1. I set this radio to a frequency that is double the 1st 'IF' and then add it to the fox frequency. This give me a radio that is relatively insensitive and can get to within 1.5 miles of the fox before sounding off. The U-R-Here radio will become full scale at about a 1/2 mile from the fox.


Larger image of the 440 beam setup.

Close-In, 70cm beam, 3rd Harmonic

Once your within walking distance of the fox, you still have to find it. I use this small 70cm beam and attenuator setup, tuned to the third harmonic of the fox transmitter. As long as the fox emanates harmonics and your within 1,000 feet, this setup works great. I can get within a few feet of the fox.

Larger image of the Xplorer.

Using the Xplorer Test Receiver.

This expensive test receiver fills some gaps left open by the 70cm beam and 2-meter/frequency counter setup. However, I don't think its worth the expense or setup  inconvenience. The range on this device, connected to the 2-meter beam is around 1/4 mile and can get within about 30 feet of the transmitter before it saturates the receiver.


AHHA MicroFinder Doppler KIT

AHHA MicroFinder Doppler
MicroFinder Doppler Control Unit
Vehicle Setup
Doppler Vehicle 1998 Jeep Cherokee
Doppler setup in my 1998 Jeep Cherokee
Jeep Cherokee
1998 Jeep Cherokee T-Hunt vehicle.
Doppler Vehicle, 1998 Jeep Cherokee Classic

Fox Controller KIT

My latest fox box. PicCon Controller, Yaseu FT51R, battery and cooling fan.

Raycon 6805 Fox Controller KIT

Fox Box
Larger image of the Fox Box.
Fox transmitter & Controller in an old ammo box.
This transmitter can be programmed and turned
on remotely. It can also be used as a cross band repeater.
Larger image showing the inside of my Fox Box.
Controller, battery, cooling fan and transmitter.
Ready to be programmed and turned on.
Continuous operation at 5-watts for 7 hours.

FOX2 Transmitter & Controller KIT

Web site of the Home brew FOX Transmitter Kit.
Designed by: James Lee N1DDK
This little Fox2 Transmitter kit is quite neat. Its PIC controlled, PLL synthesized, low cost and ready to build.

James Lee designed this Fox2 Transmitter, had the circuit board etched and gathered all the parts to make this kit complete and ready to build.


Using a serial interface with a computer terminal or laptop, you can program the:

* ID message
* Speed of the Morse Code ID
* Off time between transmissions
* Hang time between transmissions
* Arming delay time, ie: begin hunt in 60 minutes.
* Change between THREE FOX frequencies.

For more information and the DESIGNER'S WEB SITE, Click on the FOX2 button.



Send mail to [email protected] with questions or comments about this web site.
Copyright 2000 Sakane Lock & Security