What You Need to Get Started in ARDF
You do not need a lot of expensive gear to compete in Amateur Radio Direction
Finding (ARDF) competitions! Compared to many hobbies (including most other
activities in Amateur Radio) the cost of the simple handheld radio direction
finding equipment you need to participate can be quite reasonable. In fact,
if you already own an HT for 144 MHz, you have most of what you need already
to get started on two meters!
Gear for 144 MHz Competitions
A WB2HOL design two meter yagi and a VK3YNG design two meter ARDF receiver.
For two meter ARDF competitions, there are three general options for
equipment: an all-in-one ARDF receiver imported from eastern Europe,
a separate yagi antenna and ARDF receiver, or a separate yagi antenna,
offset attenuator, and HT or handheld scanner. European ARDF sets
are not especially easy to find in North America, generally only cover
144-146 MHz, and typically only receive AM and CW. Most newcomers to
the sport in North America will start with a separate antenna and
receiver or receiver/attenuator combination.
A majority of the active ARDF competitors in North America use three-element
yagis made from steel tape and PVC tubing. You won't be able to buy these
from a ham radio store, but they are easy to build from parts you can buy
at any hardware store and your local
Radio Shack. Some very easy-to-follow instructions to build one of these antennas
are available online thanks to Joe Leggio WB2HOL. Not only are these
yagis inexpensive to build, the flexible steel tape holds up to significant
abuse in the trees and bushes. You can easily build a single yagi for under
$20 in parts, or for less if you build more than one at a time.
A K0OV design two meter offset attenuator, assembled inside a
PVC enclosure built into the boom of a tape measure yagi.
There are a few specialty receivers designed specifically for ARDF on
two meters that are available on the market today. By far the most popular in
North America right now is the VK3YNG Foxhunt Sniffer Mk4, sold by Bryan
Ackerley VK3YNG, of Melbourne, Australia. This receiver includes auto-ranging
attenuation and an audio S-meter. Over half of the competitors at recent
USA ARDF championships have been using this receiver. Bryan has been able
to keep the price under $200 USD per unit to avoid customs duty for his U.S.
customer base, and he can accept payment in a variety of ways.
Another option for those who already have 144 MHz HTs or handheld scanners
is to use an external offset attenuator. An offset attenuator typically
provides up to 100 dB of continuously variable attenuation. The more
you need to attenuate the signal to keep it at a reasonable audio level,
the closer the transmitter might be. The VK3YNG receiver described above
does this automatically - with an offset attenuator, you need to pay
attention to the manual setting. The two easiest sources for offset
attenuators are the Arrow
Antennas OFHA which comes built and tested for $59, or you can buy a
from Marvin Johnson KE6HTS for $15 and build it into your own enclosure.
Some have even built the offset attenuator into the PVC boom of their
tape measure yagi!
If you already have an HT or handheld scanner, you can build a simple
three-element two meter yagi and an offset attenuator for under $50.
If you get excited about ARDF, an additional investment in a specialty
ARDF receiver is still less than most mobile ham radio rigs.
Gear for 3.5 MHz Competitions
For eighty meter ARDF competitions, almost everyone uses radios with the
receiver and antenna integrated into a single unit. The main difference
is whether the antenna is a magnetic loop design or a ferrite rod design.
Ferrite rod designs can be physically smaller and lighter weight, but
may not have the same sharpness in antenna pattern. Most competitors at
recent North American ARDF competitions have been using magnetic loop
design rigs, but mostly it is a matter of personal preference.
A WB6BYU design eighty meter receiver, built by Jerry Boyd WB8WFK
before the kits were available.
Many eighty meter ARDF rigs used in North America today are European
models that have been imported by individuals. The Altai 3,5 and others like it from Russia, the
Ukraine, or the Czech Republic have been used in eastern Europe for decades.
There is, however, no reliable source for these receivers in North America,
so if you really want one, you might have to find some member of Team USA
going to a World Championships who might be willing to shop around on your
behalf and bring one back for you. Depending on the popularity of the model
and the prevailing currency exchange rate, you could spend $100 to $150,
Probably the best option for buying an eighty meter ARDF receiver in
North America is the WB6BYU design receiver being sold both as a
kit or assembled/tested
by Marvin Johnson KE6HTS. The WB6BYU receiver is a magnetic loop design,
and details on its construction were published in the September, 2005
issue of QST magazine.
Several WB6BYU receivers have been used by USA ARDF champions. Assembled
and tested, the receiver is under $100 - a complete kit is $60.
If a ferrite rod antenna design is more to your liking, there are offerings
from overseas, including a kit from Bryan Ackerley VK3YNG
and several models
available for sale from Jiri Marecek OK2BWN (email him for current prices.)
You don't need fancy clothing to compete in ARDF!
ARDF is an outdoor sport that includes cross-country navigation through
diverse, wooded terrain. While you can buy specialty clothing and shoes
for this kind of activity, from
vendors, you don't need to invest in anything special to get started.
You should dress in loose-fitting athletic clothing that you will feel
comfortable walking or running in for up to three hours. Most competitors
wear either long nylon pants or
gaiters to protect their legs from undergrowth like fallen tree
branches or sticker vines. Some competitors also choose to wear long
sleeve shirts for the same reason. You should wear comfortable trail
or running shoes. They should have some tread to handle trail and forest
floor conditions, but they do not need to be heavy hiking boots!
This simple baseplate compass sells for under $15.
You will need a magnetic compass to help navigate in the woods. A simple
baseplate compass will work fine and can be purchased in many retail stores
for $15 or less. You need a marking pen or pencil of some sort to draw
bearings on a topographic map. You should carry a whistle, in case you fall
and are injured on course and need emergency assistance. You should also
have a watch so you know how long you have been on course. You want to make
sure that you return to the finish line under the time limit (or at least
before the search and rescue team is sent out to look for you!)
What else should you bring on course? If you expect to be out on course
for more than an hour, you should carry water, either in a water bottle
that you can carry in a waist pack or in a hydration system you carry on
your back. You might want to stuff a bite-size candy bar or some salty trail
mix in a pocket if you think you will be on course for a long time - you can
burn a lot of calories and lose a lot of sodium in three hours! On sunny/hot
days, a hat and/or sunscreen might be a very good idea - even though a lot
of your travel will be under the forest canopy, trails and meadows can
expose you to a lot of direct sunlight.
ARDF is a very approachable and fun amateur sport. While the radio equipment
you need to participate is not very common, neither is it very expensive.
You can save money by building from kits or designs available on the web.
Even buying radios built, tested, and ready to go, the cost is quite moderate
compared to other Amateur Radio activities. Add in the cost of a magnetic
compass, a water bottle, and some simple clothes and shoes for running
through the woods, and ARDF is still a small investment in big fun!