Uncategorized – Open ARDF

Radio Orienteering Cyber-Coach

ROCCy came down with a nasty cold after OpenAI updated their API a few months ago. But now he seems to be up and at ’em again and better than ever.

His name is Radio Orienteering Cyber-Coach (ROCCy for short). The Cyber-Coach will answer any question related to Radio Orienteering. It might not always get the answer entirely right, but the coach usually gets it mostly right. Please let me know if you discover important topics the bot knows nothing about or is badly mistaken.

ROCCy also speaks many languages, so feel free to ask questions in Spanish, French, German, Chinese, Japanese, Russian, Portuguese, or any other language you speak, even English.

ROCCy sticks to the topic it knows best: radio-O. So if you ask it, “What is a fox?” you’ll get a radio-O answer that has nothing to do with furry-tailed critters. It has built-in knowledge about obscure subtopics, so you might be surprised when you receive detailed answers to questions about past competitions, radio gear, propagation, and other subjects.

You’ll find ROCCy in the lower right corner of this website. Just click on theicon.

Thoughts on Beginner Classes

Even though our radio-O classes are offered through our local orienteering club, many of our beginner students are not good orienteers. For some, it is their first orienteering experience of any kind. Thus, foxoring is not a good format for them to start with: they’d need to learn how to orienteer while learning to use the radio.

Instead of foxoring, we start beginners on a small classic course. We offer a series of two or three classes. The first two classes have the students go out as a small group, and an instructor walks the course with them and is always there to instruct or answer questions.

Class #1 uses constantly transmitting foxes on a ~1.6 km long, simple course with no maps and no compasses. This first class is all about learning to use the receiver and interpret what the signal is telling them. That is plenty of challenge for most first-timers.

Class #2 uses a tiny (4-5 km long) classic course in which students learn to use a compass to continue navigating toward foxes while they are off the air. A reverse rose compass is always attached to their receivers! Students might also carry a map to help them realize how few hands they have and how important a map holder is – and they can practice some basic orienteering.

Class #3 has a small (4-7 km) classic course, and students might be assigned just three foxes to find. They are still learning to handle cycling foxes, and three foxes are usually challenging enough. This class focuses on learning to use their receiver, map, and compass to draw a single accurate bearing toward each fox. Adults comfortable doing so can go alone on the course.

Those who continue beyond Class #3 learn more advanced skills like taking crossing bearings, determining optimum order, and other skills. We no longer consider them beginners after Class #3, and they (those who are not minors) are encouraged to go out alone on regulation courses.

An alternative approach would be to restrict radio-O to only those who have attained a certain level of orienteering experience. I don’t favor that approach because it discourages newbies by introducing a hurdle they must clear before trying radio-O. Since radio navigation can be safely accomplished without a map or compass (if the terrain is not hazardous and there’s a reliable homing beacon), orienteering newbies should be encouraged to give it a try. They and expert orienteers will be equally challenged in Class #1.

If one has a class full of good orienteers, then teaching Class #1 in the same manner (receiver only; no map and no compass) still makes sense. Orienteers generally don’t seem more radio-savvy than the average beginner, so they should start by concentrating on the radio. Then, Class #2 might feature a small (or even a regulation) classic or foxoring course. If the students are fit enough and have the time, the first two classes could be held on the same day – though I don’t think that is ideal. After Class #1, a student has a pretty good idea of what radio orienteering is all about and has an inkling of whether the sport is for them – so most of the attrition occurs after Class #1. It is better to dedicate one day to Class #1 so those who don’t wish to continue beyond it can opt out of additional training without inconvenience or pressure.

Growing the Sport

Radio Orienteering is interesting to many people. We’ve found that getting people to give it a shot isn’t difficult. We’ve had as many as 20 individuals show up for a single Saturday beginner session. What is more difficult is getting people to come back. Nadia, KO4ADV, seems to have hit on a winning formula for getting folks to return.

Getting people to come back requires at least the following elements:

1. Training – most folks have never laid hands on a radio-orienteering receiver. Start with the very basics: this is how you hold the receiver, this is how to adjust the volume, this is how to turn it on, etc. Walk with them while they navigate to each transmitter until it is clear that they understand how to use the receiver effectively. (For most folks, getting the knack will require two or three found foxes.)

2. Focus – focus on using the receiver. Don’t even provide maps or compasses for the first lesson. Use constantly-running transmitters each on its own dedicated frequency. Beginners might be ready to advance to cycling transmitters by their second lesson, but they should not go out alone. Instead, on a short course, show them how to obtain a bearing direction while a fox is transmitting and then follow in that direction using a compass while the fox is off the air. Maps can be introduced in the second lesson, but drawing bearings and deciding on a proper order for finding foxes should wait for a later lesson. Going solo on a small classic course should not happen until at least two lessons have been completed and the student has confidence in always being able to navigate to the finish beacon.

3. Equipment – have enough equipment for everyone to have their own receiver. We use R3500D Chinese receivers (the latest design and factory-built) for first-timers and have found them to work well enough for that purpose, and they are cheap enough to buy in bulk.

4. Opportunity – let everyone know when their next practice opportunity will be. Ideally, it will be no more than one week after their final beginner lesson. Give them a near-term opportunity before they forget what they’ve learned. Provide monthly practices (or more frequently) throughout the year.

We’ve been following Nadia’s formula for the past year. Note that BOK has sent ten participants to the 2023 USA Championships (one-third of all registrants!), and eleven competitors to the 2023 World Championships (over half the US team!) Radio orienteering has been on the rise in North Carolina. That’s undeniable. But it didn’t happen with 2-times-a-year practices.

Early Days of Transmitter Hunting

The following account of a 1926 “Field Day” foxhunt makes for interesting reading. It had three hunters, one fox, and zero transistors. All the radio equipment was made with vacuum tubes (valves). The story is from Wireless World’s July 21, 1926, page 83-84. PDF versions of Wireless World can be found at https://worldradiohistory.com/Wireless_World_Magazine.htm

Fun With ‘Phones

They’re an essential part of a radio orienteer’s equipment. Without them, your receiver would be worthless. Some prefer headphones, others earphones. But whichever you choose, you want them to be comfortable and secure and to deliver ample sound to your ears.

It is true that, in a pinch, just about anything that delivers sound waves to your eardrums will get the job done. But high-fidelity audio has its benefits. It allows knowledgeable radio orienteers to discern perturbations in the received signal that distinguish reflected signals from the direct signal or to accurately gauge a subtle climb in signal strength confirming progress made toward the fox. So your choice of earpiece can make a difference. Here are some things to consider when selecting your radio-orienteering ear gear.

Once upon a time, it was easy to find single-ear and monaural 2-ear devices. These are almost nonexistent today, so they will not be discussed here. Only stereo 2-ear devices are considered. Almost as long ago, high-impedance headphones and earphones were widely available and would be incompatible with most radio orienteering receivers built in the past 20 years. That’s something to be aware of if you scrounge the junk box for old earpieces. Most new earphones and headphones are ~32Ω impedance, and most radio orienteering receivers sold today are designed to work with them. So don’t be too concerned about impedance unless you are dealing with older or homebuilt equipment.

High-end headphones and earphones may not be what you’ll want to wear while running through the woods in all kinds of weather. Although high-end earpieces should work very well for radio orienteering, and come with lists of cool features commensurate with their price tags, you are unlikely to find waterproof listed among their features. And Bluetooth connectivity, if required, will likely entail adding a Bluetooth transmitter (covered below) to your receiver to make it compatible. Noise cancelation would be a nice feature to have, and a pass-through mode for holding conversations would be sweet. But along with such features comes the need for the headset to have its own battery, which must be kept charged. In the end, most of us will find simple wired headphones and earphones work just dandy for this sport.

Headphones or earphones? Headphones are worn entirely outside your ear. Earphones go just inside your ear. Both are suitable for radio orienteering. Let’s explore them.

Headphones

Headphones come in two types: over-the-ear and on-the-ear. As their name suggests, over-the-ear headphones feature ear cups that entirely surround the ear and have padding that rests against the side of the head.

On-the-ear headphones have smaller ear cups with padding that rests on top of the ear. Both over-the-ear and on-the-ear use a headband of some sort to hold the ear cups securely over both ears. Over-the-ear has two significant advantages over on-the-ear headphones: 1) they more effectively seal out ambient noise that might distract from the received signal, and 2) they can fit more securely on the head and are not as susceptible to being dislodged by the vibrations of running and jumping. But on-the-ear headphones have the advantage when it comes to price and weight.

Earphones

Earphones also come in two varieties: those that rest just within the ear canal and those that rest on the concha just outside the ear canal. Naming conventions vary, but the latter are sometimes referred to as “earbuds,” so we’ll use that term too. The former we’ll call “in-canal earphones.”

In-canal earphones feature rubbery or spongy cushions that rest against the walls of the ear canal, helping to seal out external noises much as over-the-ear headphones do. And the cushion within the ear canal can also help keep them from slipping out during a competition. But some earbuds, particularly those designed to be worn during exercise, include a headband or behind-the-ear hook that holds them in place better than in-canal earphones lacking that feature. If you have some earphones you like, but they don’t stay securely in your ears, explore adding your own headband to help keep them in place.

The choice of headphones or earphones is a matter of personal preference and price. Both can deliver excellent sound. Both have options that will help them stay securely attached to you. But they both have an Achilles heel: that piece of wire with a penchant for getting snagged on branches: the cord. When snagged, you’re lucky if the cord only tugs the headphones off your head. Too often, the tug will break one of the essential wires inside the cord, leaving you deaf to the foxes’ signals.

Snaking the cord carefully through your shirt sleeve can help guard it against the tugs of trees and bushes. Attaching the cord to your clothing with several safety pins can help prevent tugs from yanking on the vulnerable plug and speaker connections. But even with all the defensive measures in place, the cord remains a vulnerability. Cords wear out. They are constantly being twisted and turned, causing their delicate wires to wear and break. So always (ALWAYS!) carry a spare earphone. The spare can be a bargain basement earphone (that thing the airline gave you and you stuck in a drawer). Pin it to your jersey, or place it inside a zipped pocket. Having a spare can mean the difference between completing the race with only a minute lost, or having to orienteer your way to the finish only to receive an OT.

Bluetooth

Nowadays, the headphone cord is optional: you can opt for Bluetooth headphones or earphones. What’s that? You say your receiver does not provide Bluetooth support? There’s a fix for that: Bluetooth support can be added using a Bluetooth transmitter.

There are two very important criteria for any Bluetooth transmitter product you choose to use for radio orienteering: it must provide reliable audio to your Bluetooth earpiece, and it must have low latency. The critical need for reliable audio is obvious, but low latency is almost as important. Your transmitter and Bluetooth earpiece must work together to provide audio with very little audio delay (latency). Otherwise, there will be a discernable lag between turning the antenna and when you will hear the resulting change in signal strength. That lag can result in bearing errors.

You must run some tests to determine if reliability and latency will be acceptable. Test your Bluetooth transmitter as soon as it arrives, and hold onto any receipts in case you need to return it. Attach the Bluetooth transmitter to your radio orienteering receiver, then pair it with your earpiece. Once paired, turn off the Bluetooth transmitter and earpiece. Turn them both on again. Do they quickly find one another and re-establish the audio flow every time? Repeat this test several times. There should be no problems getting audio to both your ears within ~10 seconds of powering up. And audio should continue to flow uninterrupted for hours, without significant glitches.

To test for acceptable latency, tune your radio-orienteering receiver to a signal and adjust the audio gain to a comfortable level. Point the antenna for maximum signal strength. Then quickly turn the antenna for minimum signal strength, then back again to maximum, and repeat. The volume of the sound in your ears should closely track the motion of the antenna. If the lag slows down your ability to quickly determine the precise antenna headings for maximum and minimum, then the lag is excessive.

Note: as of this writing, the author has not discovered a Bluetooth transmitter and earpiece combination that meets the two most important criteria (reliable audio and low latency). But I’ve only tested one highly-rated transmitter and earphone combination thus far. Bluetooth technology has come a long way and continues to improve rapidly. Acceptable hardware is probably out there somewhere or soon will be. Leave comments on what your results are.

While adding a Bluetooth transmitter and headphones or earphones will eliminate cord failures, it will also add new ways for your audio to fail. But hopefully, if you keep all batteries charged, failures will be less likely than when using a cord. But going Bluetooth is not likely to remove the requirement to carry a spare (plug-in type) earphone!

In addition to kicking the cord, going Bluetooth has another advantage: it provides more headphone options. Perhaps you already own a Bluetooth earpiece you’d like to use for radio orienteering. Bluetooth might prove to be your low-cost option in this situation – and provide some really cool features to boot.

Keep the Wet Out

Radio orienteering is played in all kinds of weather, which is a problem when it rains. Oh, you’ll muddle through and dry out with no harm done. But what about your radio equipment? Transmitters and receivers do not tolerate moisture. Water can render them temporarily inoperable or even damage them permanently. So it is imperative to keep water where it belongs: outside the equipment case.

The case surrounding the sensitive electronic innards of your equipment might look waterproof, but unless you’ve taken measures to make it so, it is a sure bet that it leaks like a sieve. Anywhere that water can seep, it will do so. That includes every hole, seam, and joint. It also includes all jacks, buttons, switches, and shafts. If it passes through the wall of the enclosure, it can leak.

So what to do? The answer: everything you can to keep water from penetrating the equipment box. There are several layers of defense. Let’s start with the outermost and work our way in.

Rainhat and Galoshes

The simplest, and least effective approach, is to keep the water from reaching the equipment. That can be accomplished by shielding the equipment with a suitable raincoat. A plastic bag can be quite effective for keeping rain from reaching a stationary transmitter. A bag is less effective for shielding a portable receiver swinging in a runner’s hand. First, the antenna elements will generally be too large to be inside, so they must penetrate the bag, resulting in holes for water to enter. Then there’s the headphone cable – creating yet another hole. Operating the receiver will require pinching knobs and switches through a layer of plastic or adding a large hole for the hand to fit through. Duct tape or electrical tape can help seal around all the punctures in the bag, but such measures might not last through a soggy race. The bottom line: bags are an unreliable method for protecting radio-orienteering receivers and should be used only as a last resort or as an extra layer of protection.

Sealing the Box

The next line of defense is the equipment case itself. Seams and gaps at panel and box interfaces can be covered by duct or electrical tape. They can also be filled using “Liquid Electrical Tape,” silicone glue, sealant, Plasti-Dip, or suitable paint.

When the gap involves a removable panel providing service access (like a battery compartment cover), the filler material needs to be temporary. Silicone paste (aka waterproof dielectric grease) is perhaps the best temporary filler. It is thick and long-lasting, harmless to rubber or plastic, and remains a thick paste even at high temperatures (unlike petroleum jelly). Silicone grease can be applied to jacks, switches, and around potentiometer shafts, where it will help seal out moisture even when those items are moved, rotated, or a plug is inserted. The downside to silicone grease is that it is messy and slippery when eventually, it spreads around the case and to other objects that come into contact with it. But it cleans up readily with soap and water or some rubbing alcohol. Some formulations are toxic and can irritate the eyes and skin. Follow label directions.

Putting some silicone grease into the headphone jack will do a good job of sealing it against water. The headphones simply plug in as usual, pushing the silicone grease aside, but leaving enough of it to seal around the plug. It is just the kind of application that silicone grease is designed for. Consider keeping some silicone grease available in your equipment bag for use on wet days.

Sealing Inside the Box

Inside the receiver’s enclosure, you might be able to access the backsides of the panel-mounted components. Sometimes, the back of a jack, potentiometer, or switch can be safely and readily coated with a sealant. Care should be taken to ensure the sealant does not seep into the component and damage it. Thoroughly sealing the back of a jack, switch, or potentiometer can effectively block moisture that would otherwise leak through. While sealing inside the box will keep water from getting inside the enclosure, it does not prevent it from getting inside the sealed components. Jacks, potentiometers, and switches with inward-facing surfaces sealed, still need to be protected from the outside or be thoroughly dried and treated with contact cleaner after any exposure to water.

Once your equipment’s enclosure is thoroughly sealed, you might consider placing a small pack of desiccant inside it. The desiccant will remove moisture from the air inside the device. The resulting extremely-dry air is ideal for extending the life of electronic devices and will prevent condensation from forming on surfaces inside the enclosure when the device gets cold. The desiccant packet will need to be replaced (or recharged by heating) periodically, typically every 6 to 12 months.

Sealing the Board

The last line of defense against water is at the board level. Printed circuit boards (PCBs) can be coated to protect them from moisture. A thorough conformal coating can render a PCB sufficiently waterproof to continue functioning normally even if immersed in water. But you might want to stop short of fully encasing a PCB in conformal coating. Many PCBs include trimmer resistors or capacitors, which would be rendered inoperable if sealed inside a conformal coating. Adjustable components such as those would be best left uncoated.

Oxidation is Our Enemy

There are two kinds of radio orienteering equipment: that which is experiencing electro-mechanical problems; and that which will experience electro-mechanical problems. You know the symptoms: volume controls sound scratchy, frequency controls cause unpredictable jumps, earphones sometimes don’t provide sound, and buttons and switches need to be jiggled before they will operate. Your previously reliable transmitter or receiver can no longer be counted on to function. Disaster! But there is a way to avoid most of those problems.

The Cause

Electro-mechanical parts will suffer whenever electronic equipment is placed in humid or dusty conditions. Electro-mechanical parts include buttons, switches, potentiometers, adjustable capacitors, jacks, and plugs. Pretty much anything that moves and contains mechanical wipers or contacts belongs in the electro-mechanical category.

Electro-mechanical components that are not hermetically sealed are vulnerable to the effects of humidity and dust. That’s because those devices rely on their surfaces remaining clean and electrically conductive. Oxidation occurs when these surfaces are exposed to the air, especially moist air. Impurities collect on surfaces when the air surrounding them contains dust or aerosols, and air always contains some level of moisture and dust. Oxidation and impurities are poor conductors of electricity and will eventually result in intermittent contact between otherwise-conductive surfaces.

Keeping your equipment clean, and storing it in a dry and clean location, will delay the onset of problems. But, eventually, the day will come when problems arise. Fortunately, there is usually a cure.

The Solution

Contact cleaners can save the day. Contact cleaners are available in spray cans or liquid dispensers sporting small nozzles or applicator brushes. Just about any contact cleaner product that advertises itself as safe for electronics and plastics will effectively remove oxidation and contaminants from electro-mechanical components and thereby restore them to normal operation. It is just a matter of figuring out how to get the cleaner to the surfaces needing cleaning. Sometimes that is easily accomplished, but some components prevent access to their innards where those surfaces are located. Applying generous amounts of contact cleaner to the outside of an electro-mechanical component while operating it will usually result in the contact cleaner working its way into the component and reaching the surfaces needing a good cleaning.

Some contact cleaners are “no residue.” After application, they dry completely, leaving nothing behind. No-residue cleaners perform their cleaning action only while they are in contact with a surface, helping to dissolve and remove contaminants where surfaces rub against each other, and then they are gone. No-residue cleaners are good for cleaning plugs and exterior surfaces where you don’t want to have anything that might get on your hands.

Other contact cleaners leave behind a protective film. These products are sometimes called “lubricating.” After their solvents have dispersed, a thin protective layer remains that lubricates and helps delay oxidation’s return. Lubricating contact cleaners are well-suited for equipment that will spend part of its life outdoors or in moist conditions.

Both no-residue and lubricating contact cleaners can be applied preventatively before problems occur. The periodic application will help avoid unexpected equipment problems. Despite being safe for plastic, both types of products contain solvents that might dissolve paints, dies, and ink. So avoid getting them on any vulnerable markings you have applied to your equipment.

GPS Device Approved for Orienteering

Garmin’s Enduro ultraperformance multisport watch has become the first GPS-enabled watch authorized by Adventure Race.

An Adventure Race is a multisport orienteering competition held on extremely rigorous terrain. When a user sets the watch for the Adventure Racing activity, location information is recorded but unavailable for racers to view during the event. Because Adventure Racing and orienteering competitions do not allow GPS navigation, users are not able to view GPS-based data fields, but they can still record a log of their track.

With Garmin Enduro, competitors can monitor and record biometric data like heart rate and will be able to use other functions of the watch like altimeter, compass, alarms, and timers. A verification page shows when the activity began and ended, allowing competitors to prove to an official that GPS navigation was disabled during the race.

Perhaps this will be a trend among device manufacturers, allowing the sport of ARDF to permit the Enduro and similar devices without violating ARDF’s requirement for competitors to rely only on their personal map-and-compass navigation skills.

Why are Smartphones Different?

GPS White Paper

Ranking Part 3: Ranking Criteria

Part one of this series of blog entries presented one reasonable approach to scoring ARDF competitions. Part two described a way to adjust competitor scores to make them apple-to-apple comparable from one event to the next. Part three examines how the adjusted scores might be brought together to provide a meaningful ranking system for USA ARDF athletes.

The goal of creating a ranking system is to display competitors’ names by order of their overall ARDF performance over some period of time. That is, their names should be ordered 1st, 2nd, 3rd, etc. based on how well they performed in recent ARDF competitions. Certain standards and criteria need to be applied in order to determine who gets ranked, and how their rank is determined. This post examines what some of those standards and criteria might be. It is not meant to impose any particular set of standards, but rather to present one approach that can serve as a starting point for discussion.

A competitor’s rank is just one criterion that might be used when selecting team members. Being highly ranked does not guarantee that a competitor will receive an invitation to join the team. Conversely, not being listed among the rankings does not mean that an individual won’t be selected for team membership. The team selection subcommittee is free to utilize all reasonable criteria to ensure that the team selection process is fair and equitable. Rankings are just one tool they may use to assist with the team selection process.

Who To Rank

A ranking system should not attempt to include every individual who has ever played the sport. It is fitting that only those who have demonstrated a certain mastery of the sport be included in the rankings. So the proposed system selects those individuals who meet the basic requirements.

Since the rankings are for USA competitors, it seems fitting that only those who might qualify for USA team membership be included. The USA ARDF Rules currently describe the basic requirements as follows:

Competitors eligible for USA ARDF Champion shall be citizens of the USA, Green Card holders, or have lived in the USA for the previous year and shall not have competed for the title of Champion in any other country.
USA RULES FOR AMATEUR RADIO DIRECTION FINDING Version 9-Feb-2020

Recent competitive ARDF experience is also an important criterion. Having met the basic requirements for team membership, ranked competitors also need to have competed in at least one recent ARRL-sanctioned ARDF event, and to have demonstrated a minimum level of mastery of the sport.

A suggested definition for a recent competition is an ARRL-sanctioned ARDF competition held during the two most recent calendar years in which ARRL-sanctioned events were held. Usually, that will be competitions held during the current year and the previous year. But COVID-19 demonstrated that there might be years in which no ARRL-sanctioned ARDF events are held.

As a minimum level of ARDF mastery, the suggested measure is this: in at least one recent sanctioned competition the competitor must have successfully located all assigned transmitters and registered at the finish before the time limit expired. In other words, they successfully completed at least one course. One might ask, “Why not rank everyone who didn’t OT?” There are two main reasons why assigning a rank to an individual should require a higher minimum standard: 1) It gives greater significance to the achievement of attaining ranked status, and 2) It may not be feasible to calculate an accurate rank for all who participated.

Expanding on the second point: consider that in a 5-transmitter M21 Classic competition a 5-fox minimum requirement results in just one possible combination of foxes and only one permutation that must be selected as the optimum order. But for those who find only four out of five foxes, there are five different combinations of foxes that must be analyzed to identify the one permutation that is the optimum order. If three out of five foxes are found then there are ten different fox combinations and ten more optimum permutations that must be analyzed. For two out of five foxes there are again ten combinations and permutations to be analyzed. And if only one fox is found there are five combinations. That means that there is potentially 5 + 10 + 10 + 5 = 30 times as much ranking analysis required if “not going OT” is used as a minimum ranking requirement in a five-fox competition. And that is just for the M21 category. When there are few competitors this will be a manageable problem, but clearly, setting too low a bar does not allow the ranking system to scale.

Remember that being ranked is not a prerequisite for being selected for Team USA. So not being ranked need not exclude any qualified individual from making the team. The Team Selection Subcommittee has latitude to take into account other factors, including extenuating circumstances when extending invitations for team membership. So, as a practical matter, restricting the number of those ranked, and having the team-selection process consider unranked individuals using a non-analytical methodology is the most reasonable approach.

Calculating Rankings

A competitor who meets all the criteria described above will have their rank calculated and listed in the rankings tables. Separate rankings will be calculated for each competition format: Classic 80m, Classic 2m, Sprint, and Foxoring. Within each format rankings table, the competitors will be ranked separately by age/gender category.

All qualifying competitors are eligible to receive up to four separate rankings: one for each competition format. Those rankings will be made relative to all other qualifying competitors in their age/gender category.

A competitor’s adjusted competition scores (see Part 2) will be used for determining rank. Only the highest event score achieved during a calendar year will be considered. (This will ensure there is no disincentive to participate in multiple events annually.) The highest score from both recent years will be averaged to determine a competitor’s ranking score. If the competitor only participated during one recent calendar year, then that year’s highest score will be the competitor’s ranking score. A competitor with a higher ranking score will be ranked above any competitor with a lower ranking score. Tied competitors will both receive the same rank, with the next lower rank(s) left vacant.

If a competitor lacks results from recent competitions because he/she helped conduct a sanctioned event, then their rankings will be calculated using the two most recent years for which they have qualifying results, going back up to four years.

Discussion

No ranking system is perfect. The one described above is no exception. But it does have simplicity working in its favor. The formulae it uses are simple, provably stable, and give predictable results. The entire system can be written in a short Javascript program and rendered on any browser. The results, and the source code, can be shared freely so that competitors and organizers can analyze it and improve upon it.

Ranking Part 2: Adjusting for Difficulty

ARDF is conducted in nature. So, like golf, mountain bike racing, or skiing, the venue influences the game’s difficulty level. Navigating in a sparse forest is easier than in jungle-like undergrowth. Running on flat smooth terrain doesn’t require as much effort as climbing steep rocky hills. Some ARDF courses are going to be more difficult than others, and that will always be the case.

So when a competitor scores highly on a difficult course it says more about his/her fitness and skills than acing an easier course. And because an ARDF score is derived from one’s finish time relative to other competitors on the course, prevailing against stiff competition is also a better indicator of an athlete’s skills and fitness level.

Venues across the USA have diverse terrains, and course difficulty can vary widely. So if we are going to compare scores achieved in competitions held at different venues those scores need to be adjusted accordingly. Ideally, the scoring system would be designed to handle adjustments automatically. In orienteering this is accomplished by calculating scores relative to the average times of the top finishers. Because orienteering competitions consistently have a sufficient number of highly-skilled entrants, the top performances establish a good baseline by which to compare the subordinate finishers.

But many ARDF categories at USA events lack highly-competitive entrants and sometimes contain only a single competitor. So the question arises: how to adjust ARDF scores to make them comparable from one event to the next?

Ideal Time

One proposal is to utilize the concept of ideal time ( $T_{i}$ ). Ideal time is the expected finish time for an elite ARDF athlete traversing a course with the following results:

Finds each assigned transmitter in optimum order following the shortest practical route based on the competition map;
Unaffected by chance. E.g., doesn’t find any flags off-cycle, makes no wrong turns, etc.;
Runs at a speed that is realistic for his/her age and gender category taking into account the running conditions present along the route followed.

Note that ideal time is not YOUR ideal time, nor is it the ideal time of any of the competitors in the competition. Ideal time represents what a healthy elite athlete should be able to accomplish without anything unpredictable happening.

There isn’t currently a software program capable of calculating ideal time, so it is a manual process. Although it is a manual process, it is not very difficult, and the process can be documented in detail in order to allow almost anyone to perform the calculation. Calculating ideal time involves spending some time analyzing the competition map, plotting the shortest practical route from start to finish along the optimum order of transmitters, and estimating a realistic speed of movement along that route. A unique ideal time is assigned for each course for each competition held during an ARDF event.

Once calculated, the ideal times represent the results that an elite athlete in each age/gender category could have achieved. Ideal time can be applied to the scoring approach presented in Part 1. By doing so, the scores of all competitors who found all the assigned transmitters will be adjusted, making them more reflective of what they would have scored had an elite athlete actually participated.

Adjusting for Competition

Calculating ideal time and inserting it into the race results has the effect of adjusting all competitors’ scores to reflect what they would have been had an elite competitor actually participated. This will be the case even for categories in which only a single competitor participated. Utilizing ideal time in this manner doesn’t require any special formulas, and the adjusted scores still reflect the correct finish order.

Examples

Consider the M40 results from a Classic 80m competition in which the ideal time was calculated to be 60 minutes (3600 seconds)and there were five transmitters for the M40 competitors to find.

(Example 1) M40 competitor “A” found all five transmitters and finished with a time of 75 minutes (4500 seconds). He had the best overall time (i.e., $T_{1} = T_{A}$ ) amongst all M40 competitors who found all five transmitters. Without putting ideal time into the results, competitor “A” would have a score of:

$S_{A} = (5 + T_{1}/T_{1})\cdot 16.7 = 6 \cdot 16.\overline6 = 100.0$ points

Including ideal time ( $T_{i}$ ) in the results adjusts the score of competitor “A” as follows:

$S_{A}^i = (5 + T_{i}/T_{A})\cdot 16.7 = 5.8 \cdot 16.\overline6 = 96.\overline6$ points

(Example 2) M40 competitor “B” who found only four of the five assigned transmitters. No adjustment for ideal time would be calculated for this competitor. Ideal time is only calculated for a course that includes all the assigned transmitters. Those who find fewer transmitters will not receive adjusted scores.

(Example 3) Let’s look at a very slow M40 competitor “C” who found all five transmitters but required the full time limit of 3 hours (10800 seconds). His unadjusted score would be:

$S_{C} = (5 + T_{1}/T_{C})\cdot 16.7 = 5.41\overline6 \cdot 16.\overline6 = 90.2\overbar7$ points

Adjusting for ideal time gives:

$S_{C}^i = (5 + T_{i}/T_{C})\cdot 16.7 = 5.\overline3 \cdot 16.\overline6 = 88.\overline8$ points

Adjusting for Course Difficulty

The value calculated for ideal time will be greater for difficult courses and lesser for easier courses. Therefore, by comparing the ideal time calculated for an actual course with the ideal time calculated for a standard reference course, a unitless ratio can be derived. That ratio can be used to adjust competitor scores to account for the course’s difficulty.

So long as the standard reference is consistent the adjustment will be fair, since it will affect all competitors’ scores identically. So, for both consistency and simplicity, a reference of one hour is suggested for Classic and Foxoring courses, and fifteen minutes for Sprint, since those are the generally-used length targets used by most course designers. This reference can be named the ideal reference time $(T_{i}^R)$ and uses the same time units (seconds) as ideal time.

The unitless ratio to be used for adjusting for course difficulty is calculated as follows:

(1) $\begin{equation*}\gamma = T_{i} / T_{i}^R\end{equation*}$

Where:
$\gamma$ is the unitless course difficulty factor,
$T_{i}^R$ is the ideal reference time, and
$T_{i}$ is the ideal time.

The more difficult a course is the greater its ideal time. If the course designer made a course so that elite competitors complete it in the targeted amount of time (1 hour Classic/Foxoring or 15 minutes Sprint) then $T_{i}^R \approx T_{i}$ so that $\gamma \approx 1$ . And as a course is made more difficult the value of $\gamma$ increases above $1$ , and less difficult courses will have $\gamma$ values less than $1$ .

$\gamma$ only applies to those factors affecting a competitor’s overall time. Therefore, only the time component of a competitor’s score should be multiplied by $\gamma$ . $\gamma$ should not be applied to the component of a score derived from the number of transmitters found.

When $\gamma$ is multiplied by the time component of a competitor’s course score adjusted for the ideal time, the result is the adjusted score ( $S_{c}^{adj}$ ) that can be compared apples-to-apples to any other adjusted score for the same type of competition and age/gender category. Since transmitter count is not involved in the computation of the adjusted score, it is fine to rescale the score without regard to the number of transmitters. So the formula for adjusted score is simply:

(2) $\begin{equation*}S_{c}^{adj} = 100 \cdot \gamma \cdot T_{i} / T_{c}\end{equation*}$

Where:
$S_{c}^{adj}$ is the adjusted score for competitor $c$ ,
$\gamma$ is the course difficulty factor,
$T_{i}$ is the ideal time for the course, and
$T_{c}$ is the finish time for competitor $c$ .

Inserting the right side of Equation 1 for $\gamma$ into Equation 2 gives the following equation for $S_{c}^{adj}$ that allows us to skip the calculation of $\gamma$ :

(3) $\begin{equation*}S_{c}^{adj} = 100 \cdot T_{i}^2 / (T_{i}^R \cdot T_{c})\end{equation*}$

Where:
$S_{c}^{adj}$ is the adjusted score for competitor $c$ ,
$T_{i}$ is the ideal time for the course,
$T_{i}^R$ is the ideal reference time,
$T_{c}$ is the finish time for competitor $c$ .

Example

(Example 4) Consider the M40 results from a Classic 80m competition in which the ideal time ( $T_{i}$ ) was calculated to be 60 minutes (3600 seconds).

With the information above, calculate the adjusted score ( $S_{c}^{adj}$ ) for Example 1. First, select the appropriate ideal reference time:

$T_{i}^R = 3600$ seconds (For a Classic competition.)

Use $T_{i}^R$ , $T_{i}$ , and $T_{c}$ to calculate the adjusted score for competitor “A” from Example 1. Using Equation 3:

$S_{A}^{adj} = 100 \cdot T_{i}^2/(T_{i}^R \cdot T_{A})$

$= 100 \cdot (3600)^2 / (3600 \cdot 4500) =$ 80.0 points

Other Comments

Because ideal time assumes no chance events, it is possible that some elite competitors will achieve finish times shorter than ideal time. When that happens in the scoring system described in Part 1, those athletes will receive scores greater than 100.0 after the ideal time is applied to the overall results. Such outcomes are acceptable and should be interpreted as indicating that some transmitters were probably found off-cycle.

The scoring methodology described in these posts does not attempt to adjust for differences between the various competition formats, competitor age, or gender. Therefore, adjusted scores must only be compared or combined with other adjusted scores for the same competition format and age/gender category.

There have been some questions regarding Equation 3 and its use of the square of ideal time ( $T_{i}^2$ ). The ideal time is squared in the calculation of adjusted score ( $S_{A}^{adj}$ ) because it is being used to compensate for two separate and independent factors: the strength of the competition, and course difficulty. So it is necessary for it to be applied twice.

Note that the adjusted score contains only a time component and therefore isn’t affected by transmitter count. The effects of transmitter count were accounted for in the calculation of ideal time and adjusted score. So it is reasonable to combine (e.g., average) and compare adjusted scores within the same age/gender category from competitions of the same format having differing numbers of transmitters.

Experimentation with the formulae above is encouraged. Their use over time will no doubt reveal improvements to this scoring approach.

Summary

Because ideal time assumes the technical skills and fitness level of an elite athlete, it can be used to adjust for the absence of strong competition at a particular event. Because ideal time takes into account the actual course lengths and terrain, it can be used to adjust for the effects of the venue on competitor scores. Because the process of calculating ideal time can be documented and repeated by trained individuals, it can be applied objectively and precisely.

But, ideal time is not an ideal solution. It would be better to have a sufficient number of elite competitors at each ARDF competition to utilize orienteering’s scoring approach. But until the day of highly-competitive USA ARDF contests arrives, the use of ideal time as presented above is a reasonable approach allowing results to be compared between events having different levels of difficulty, even when few (or no) elite competitors were in attendance.

The approach described in this writing will not impact the order of finish for any event, but it achieves two important goals:

It allows competitors to see how they would have scored relative to elite competitors like those they might find at a World Championships.
It provides a way to fairly compare scores from events held at different venues and presenting different levels of difficulty.

Number 2 above will be examined more closely in Part 3.