This was posted by Dale Hunt, WB6BYU, to the Foxlist. Dale is a former
member of SBARC and has competed internationally in ARDF competitions
Are you interested in ARDF but not sure if you have what it takes
to participate in the upcoming National ARDF Championships in
Albuquerque? Don't worry, you'll probably have a good time!
First, it is true that international-caliber ARDF competitors are
good athletes, but that doesn't mean you have to be one to
participate. The maximum course length is 7 km (about 4.5 miles)
and the time limit will be at least 2 hours. A brisk walk is about
4 miles/hour, and 3 miles/hour is a leisurly pace. If you can walk
5 miles in an hour and a half, you should be able to finish the
course, allowing some time for taking bearings, backtracking, and
waiting for the transmitter to come on.
Talk a walk around the local school track and time yourself:
4 minutes per lap (1/4 mile) is just under 4 miles per hour.
Of course, faster is better - but slow and steady will get you
If nothing else, it is a great excuse to get out for a walk each
day, even if you just walk for half an hour or 45 minutes. Don't
push yourself to the point of exhaustion or injury, however. Set
a realistic daily or weekly goal that you know you can meet, and
if you regularly exceed it, go a little further or faster each
time. If you are long out of condition (like many of us) then
start with a mile or two a day and build your endurance.
Afraid you will be out of place among the more experienced
competitors? We all have to start sometime, and this may
be one of the best learning opportunities, where you can
watch others and see how they do things. But, remember that
ARDF is still a new sport in North America, and most of the
"experienced" American competitors are still relative beginners
who have only participated in a handful of competitions.
(In 1999, KB7WRD had never tried any direction-finding until
a week before the event, and still took home several medals.)
You might be surprised how well you do!
Equipment: what if you don't have the latest imported ARDF
receiver with built-in map computer? You'll probably still
do well. You will need a receiver for each band, a compass, and
perhaps a piece of cardboard or plexiglass for your map.
For 2m, you can use your HT or scanner with a yagi and an
attenuator. (Serious international competitions don't allow
people to carry a transmitter, but for now we will just have
to trust people not to use it to talk to other competitors.)
The "active" or "offset" attenuator is a good choice - there are
several versions out on the web, and they are easy to build.
Joe Leggio WB2HOL's tape measure yagi has a good pattern and
will withstand quite a bit of beating through the bushes.
(I've hunted with a quad in the woods before, and the loops
tend to catch on branches.)
The best approach, of course, is to use something you are
familiar with, or to get familiar with the equipment you will be
using. If you typically use a TDOA system or L'Per, you may
have difficulties with the horizontal polarization. Instead of
using vertical dipoles for the antenna elements, you should be
able to use small horizontal loops, though they will need to be
tuned carefully to get the right pattern.
There are a lot of 2m HT's around, but very few 80m DF receivers.
If you have a hand-held shortwave receiver (preferably with a BFO),
you can build a simple DF loop from the ARRL Handbook or Transmitter
Hunting: Radio Direction Finding Simplified. Some shortwave
receivers use a ferrite-rod antenna for the bands below 10 MHz,
which will give a directional pattern (but will leave a 180 degree
ambiguity.) 80m DF receiver kits are available from VK4BRG and
DL3BBX. Jerry Boyd WB8WFK presented his FoxFinder 80 in 73
magazine (last November?) and circuit boards for it are available.
I'm also have a receiver circuit which Jerry has built and
tested. So there are a number of options for equipment.
But, if equipment is the only thing which is keeping you from
attending, I suggest you contact the organizers and inquire
about the possibility of borrowing equipment. For the Region 2
ARDF Championships in Portland in 1999, we arranged for some of
the visiting hams from overseas to bring some extra receivers
that gave everybody an opportunity to compete on 80m. I expect
that the organizers will try to coordinate extra equipment for
those who need it this year as well.
(The first in a series of articles to help folks prepare for
the first US National ARDF competition this summer. Comments,
questions, suggestions, and other points of view are welcome.)
- Dale WB6BYU