Santa Barbara Amateur Radio Club
Amateur Radio Direction Finding - ARDF

Beacons in the woods: Orienteering for ARDF
by Bill Pollock, KD6JY

Orienteering is finding your way over the land using a map. in its competitive form, O (as it's called for short) is a cross-country run where, instead of a marked course, the runner gets a topographic map with a number of control points marked on it. Find all the controls and return to the start; the fastest time wins.

O began in Scandinavia early in this century. Today in Norway and Sweden, it's second only to cross-country skiing in number of participants. In those countries, with a population of 12 million, half a million people orienteer, and 50,000 are avid competitors (10-15% of them women). Big multi-day competitions in summer draw tens of thousands of entrants.

Over the years, O spread through Northern and Eastern Europe, Britain and Australia. In Canada, the provinces support O with training and map-making funds, and high schools field O teams. The US is definitely an underdeveloped country in this sport; fewer than 10,000 Americans participate regularly. (In the '80s we even received some 'foreign aid' from the Swedish O Federation, to help expand the sport.) Hottest activity is in New England and the Delaware Valley. Closer to home, clubs in the Bay Area, Los Angeles and San Diego include several hundred members and promote regular competitions.

Enough history; let's start orienteering.

The Tools

Every O runner carries a map and compass, but notice I didn't mention the compass till now. Many people have sorry memories from infantry or scouting days, of having to take an azimuth and plow relentlessly on that course over rocks, marshes and poison oak, in search of some hidden marker. This grim task is not the sport of O. Smart wilderness hikers and competitive runners alike first take a good look at the map, and make sure where they are on it. They look for roads, trails, even streams that lead roughly toward the goal -- or if there are none, then they devise a series of hops between recognizable features (boulders, structures, clearings). They look at big hills, swamps and thickets, and try to go around them rather than fighting them. They pick some big features along the way to watch for, as checks on direction and distance. And then they bring out the compass, orient the map (turn it to match the terrain), relate the squiggles on the map to the visible landscape, and start moving.

(By the way, you may not need a compass every time you orient the map. A distant mountain, the line of Route 101, or (in California) the sun may serve instead.)

A national champion takes all of 10 seconds to plan a rough course to a control point which may be a kilometer away in mostly untracked woodland. In open, hill-and-dale pine woods he runs 8-minute miles, mentally counting paces to keep track of distance, and reading the map on the run to check off features along the way. (Young Swedes learn to do this by reading from their English conversation texts while on their training runs on the road!) Nobody starts out this way, of course. How do you get there? Practice, practice.

A word about the compass, since you really do need one, even if less frequently than your patrol leader told you. The kind with a clear-plastic rectangular base and rotatable degree circle is best. It lets you quickly orient the map and measure distance and direction (and for ARDF, do triangulation). And if you really have to, you can hold it in front of your belly and follow a compass bearing well enough. You don't need a compass with gunsights, reflectors or optics.They're slower and more complex to use for the tasks just described, and over the short distances we're running, their extra accuracy is of no consequence. Here's a hint: a loop of string around your wrist and through the compass will make it easier to find it (the compass) again, after you've thrashed through heavy brush, slid down a stream bank, or made a lunge to rescue your DF receiver.

Tactics and Techniques

At an O event, you may get to see the map in advance, but you won't get to see the control locations marked on the map until you step up to the start line. (In ARDF, the controls aren't even mapped -- you have to wait for each one in turn to beep at you.) Look over the map. What is its scale (or, how fast will you move across it as you travel on foot)? What is the contour interval (how high does a hill look if it's shown with two concentric contour lines)? Where are you now, on the map (the start is usually marked with a small triangle)? Compare the map with the landscape, first to get aware of really big features in the area, and second to see how the mapper has dealt with little things -- wiggles in streams, patches of dense undergrowth, rocky ground. A map is a sort of artwork, and what's drawn depends on the context. Stone walls and slabs of granite are important in New England, glacial moraines and depressions are everywhere up north, and in lowland California the chaparral varies from prickly to truly impenetrable.

When you know what your first target is, start planning a route to it. Is there a trail most of the way there? (We call that a handrail.) What are the tradeoffs of distance, undergrowth and climbing? You're slower in the woods than on a trail, so shorter might not be better. And 10 meters of climbing takes roughly as much time as 100 meters of running (sorry about that metric stuff, guys, but O maps are almost all scaled that way). Still, the top of a ridge may offer better visibility and a good handrail (and fewer echoes in ARDF), so you may just need to climb up to it.

Only rarely can you get all the way to your target on one handrail; the course-setter knows you want more fun than that. You'll need to make use of trail or stream junctions and sharp bends, and prominent boulders and knolls, called point features. They locate you accurately on the map, so they make good places for changing direction or switching handrails. Line features (you can guess what they are) crossing your route are useful for correcting your distance estimate, but don't tell you if you're off course to the left or right.

Course setters love to put controls on spurs (little ridges leading down a hillside) and re-entrants (the little valleys between the spurs), because they can be accurately located by the map's contour lines, off the trail and above or below the orienteer's sight line. To find the control, you need to select a point to depart from your handrail, know when you're at that point, orient the map carefully, and navigate on the contours, vegetation, rough compass, or a mix. The tradeoff of speed and sureness in route choices is the art of O, and much of that art is concentrated in the final detailed attack to the control.

Whole books have been written about techniques and tactics, but for a first outing, we've already got more than enough to think about. Before we close, though, please do read the next important section.

Staying Found, and what to do when that fails

Don't overrun your navigation. If you lose touch with where you are on the map, chances are you won't find yourself again until you hit a major road or river, and lose a bunch of time. Stop while you can still backtrack to a known-for-sure point.

Look for some large feature on the map (a catching feature) behind your target or control point -- a big hill, water, a cliff, something to act as a catching feature. You really want to know if you've overshot your mark.

When you start out for the day, figure out a safety bearing -- a course that, from anywhere on the map, will take you to a highway or other comforting sign of civilization. If you lose your map or it turns into a soggy ball, this may be the only way to rescue yourself. And carry a whistle; sounds dorky, but the search-and-rescue team will love you for it if you're lying hurt in the woods. (Whistles are required at many top-level O events.)

Every event has a time limit. Carry a watch, get back before the deadline, and quit earlier if you're headed for heat exhaustion or muscle fatigue. Check in with the officials whether you complete the course or not. They try hard not to leave anyone in the woods, and the search-and-rescue team will not love you if they're out looking for your remains while you're already home by the fire.

Ready to try it? Los Angeles O Club has events (called 'meets') at Schabarum Regional Park (two days, Feb 13-14); Griffith Park (March 14); Malibu Creek State Park (Apr 11); Topanga State Park (May 9); and a big one at Mt Pinos (June 12-13).

Want some armchair O before you go? Below is a section of an O map of Mt Pinos, reproduced as well as black-and-white allows. Starting at the parking lot, navigate to the circled features 1 (trail junction), 2 (knoll), and 3 (boulder group). (#1 and 2 are basic-level controls, 3 is more advanced.)