|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
(All can be purchased, over the counter and ready to
|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.
Beam. 4-element beam on 2-meters, best for initial
bearings. Good gain and narrow beam.
beam, 3-elements on 2-meters &
7-elements 70-cm also works well but, is best
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.
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
laminated in plastic. You can write on them with a
felt-tip pen and erase the markings with
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.
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
simultaneously. It really helps as a
(I have a lot more gadgets but, the above is what I use on
almost all my hunts)
Reactivating my Super
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
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.
Sakane - KD6DX
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
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
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.
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
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.
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
A good plotting protractor is also a important. Plotting your
initial bearing on a large map of the hunt area must be accurate
Close-In, Scout-40 Frequency
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
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.
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.
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.
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
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
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
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.
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
TOOLS I NO LONGER USE
U-R-Here, 1st 'IF' (your close) Radio
Next, I setup my U-R-Here radio, a
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.
70cm beam, 3rd
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.
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
MicroFinder Doppler Control Unit
Doppler setup in my 1998 Jeep Cherokee
Doppler Vehicle, 1998 Jeep Cherokee Classic
My latest fox box. PicCon Controller, Yaseu FT51R, battery
and cooling fan.
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.
Controller, battery, cooling fan and transmitter.
Ready to be programmed and turned on.
Continuous operation at 5-watts for 7 hours.
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