Author: Radio-O

The Dual-Band ARDF Transmitter design Rev X2 is in its final stages. A last-minute feature update has been added: remote control. Support for experimenting with wireless remote control of the the transmitters has been added. The concept: attach a Dual-Band ARDF Receiver to a Dual-Band ARDF transmitter via their Cloning ports to create a Dual-Band ARDF Transceiver.

A Dual-Band ARDF Transceiver will be capable of receiving remote commands using the same antenna being used for fox transmissions. A Dual-Band ARDF Transceiver will be capable of serving as the remote control station used to send commands to the foxes in the field.

The remote-control concept is experimental at this time. But the Rev X2 hardware will provide support for developing and testing this remote control concept to make it mature and usable.

Atmel code for the OpenARDF hardware project has been written in and for Atmel Studio 7. This video shows just how simple it is to port Arduino sketches to Studio 7: https://www.youtube.com/watch?v=7WnOe00dVu0

The advantage of using Studio 7, along with the Atmel ICE, is that it allows for a much more sophisticated development and debugging approach, using the full capabilities of C or C++ to control the processor, and in-circuit debugging.

I’ve had a recent exchange with an advocate for the use of GPS in ARDF. The reasons for it, and I am paraphrasing, are as follows:

1. GPS navigation doesn’t fundamentally change the sport.

2. Everyone in the world is using it.

3. We would compromise the competitiveness of Region 2 ARDFers if it were banned here.

From experience and long hours of testing, I can attest that unbridled utilization of accurate satellite-derived position data will remove much of the need for navigation skills from ARDF. If that isn’t the case today, then GPS-enhanced receiver makers are either using substandard hardware, or poor software. (There is also a third possibility.)

If you want to see the future of ARDF under current Region I rules then check out the iPhone app Map-n-Compass (available for free starting 30 Oct 2017). That app uses standard GPS position data and electronic compass information to simulate an ARDF course, complete with transmitters, and the app serving as a simulated receiver. If you don’t install a map of the course terrain, and you remove the SIM card, you’ve got an ARDF tool that meets all the current Region I rules.  In the beginner mode (default) the app allows you to see your position on the screen, record your track, see exclusion areas, record bearings, and calculate bearing crossing locations. And it will lead you almost inerrantly on a straight-line path to the transmitter of your choice.

If that doesn’t change the sport by diminishing the need for navigation skills, I don’t know what would.

While point #1 seems dubious at best, points 2 and 3 remain, and those final two points have some merit. Sadly, widespread use of GPS, and satellite navigation’s inevitable impact on the sport, means that everyone probably needs to have a GPS-assisted receiver (especially beginners in the sport) in order to be competitive with their peers so equipped.

The bar to entry into ARDF has just been raised. Or, maybe not. At least not by so much.

Rather than trying to slam the barn door shut after the satellite-following cow passed through, perhaps it is better to accept that GPS has given rise to a new event: an ARDF flavor that requires fewer navigation skills, but still uses receivers and hidden transmitters.

So a new sport is born, but what about the old one?

You know, the sport we used to call ARDF? Well that one doesn’t have to go away. Rules could allow those who prefer not to play the sat-nav version of the sport to instead elect to run as a classic competitor. Those choosing not to utilize GPS would be a different class of competitor, whose performance would be judged against others in their class, not against sat-navvers.

But it seems that the rules for Region 2 need to come into existence in order to make any of this a reality. Rules are needed in order to make it clear that traditional ARDF has a place, and so does the satellite-assisted version of the sport. The rules also need to provide for a mechanism to keep the sport affordable and accessible, by permitting approved apps to be used in competition.

It would be a shame for any IARU region to have its hands tied by blind adherence to Region I decisions. It is time for Region 2 ARDF leadership to engage, to move forward with new ideas, or explain why change is not needed, or to remove themselves as an impediment to the advancement of the sport.

Competitors purchasing ARDF receivers should be aware of a practice that has a long history in the sport: the sale of handicapped equipment. It has long been known, and openly acknowledged by some equipment sellers, that the receivers available for purchase don’t necessarily perform quite as well as the receivers the small manufacturer owns for personal use. It has long been accepted as a perk of being technologically savvy enough to design or build electronic equipment, that you may elect to keep something in reserve.

There is no reason to believe that the same practice is any less pervasive today. And with the use of proprietary software, the “kneecapping” can be done without any trace of visible hardware differences.

So if you own an ARDF receiver with built-in GPS, and the assistance it provides seems helpful, but not game-changing, don’t assume that all competitors are obtaining identical results.  Non-spectacular results might be by design, and not due to any limitation in the technology. You will probably never know all the differences between your equipment and the outwardly-identical equipment utilized by your competitors.

I would like to conclude this post with a “buyer beware” message. But the truth is, buyers cannot beware, because you can’t beware that which you have no knowledge. Only marketplace competition between receiver sellers can correct this problem – if one considers it a problem and not simply a perk. When receiver sellers must sell the best or lose your business to the competition, only then will buyers have some confidence that they’re getting the latest features and performance.

Since we can’t beware, let’s just not be naïve.

What’s going on may not be apparent to most users of “GPS-enhanced” ARDF receivers since simply listening to the audio doesn’t provide many clues as to what’s really happening under the hood. But devices that use satellite navigation signals to derive “continuous bearings” and cross track error indications, are making use of a continuous stream of GPS-derived position data that (typically) exhibits a position error of 10 meters or less. That degree of accuracy is easily on par with what expert orienteers can achieve using just a map and compass.

It also might not be obvious that a bearing consists of not just a direction, but also the position at which the direction was read. So accurate position information also enhances the accuracy of bearings.

With the use of GPS, accurate positions are derived and utilized regardless of where a competitor believes himself to be located on the map. GPS accuracy is undiminished when a competitor is tired, confused, or just a lousy orienteer. And because those positions are true and accurate, the bearings and crosstrack error indications provide highly accurate navigation guidance to the actual location of a signal source (fox), even if the competitor erroneously believes that he is headed in a totally different map direction from where his feet are actually taking him.

Most ARDF courses include some very runnable regions with little or no obstacles; though such regions might still be challenging to navigate, they can be traversed easily in a nearly straight line. A GPS device allows one to follow a straight line, accurately, and inerrantly. So on a course with no significant obstacles to movement, a map becomes an unnecessary accessory when GPS is being used. Hundreds of hours spent testing the iPhone app “Map-n-Compass” proved that to be true. The app uses GPS to provide guidance from GPS-derived position data, identical to the technology incorporated into ARDF receivers sporting GPS receivers. The more runnable the terrain, the more effectively GPS replaces the need for a map, and those skills required to read a map and locate one’s location on it.

But GPS also has an impact when courses cover difficult terrain. Consider a course with significant barriers to movement, such as dense forest, steep hills, and swift creeks. Such barriers will pose less of an obstacle to the strongest and fittest competitors, who will be better able to power over the hills, and through deep water, and more closely follow the shortest straight-line route between foxes provided by the GPS-derived crosstrack error. With two equally-skilled navigators, both using GPS, the advantage will swing decidedly in the direction of the one who can best follow the continuous GPS-derived audio-indicated straight-line path. So GPS swings the advantage to those who are most physically fit and powerful, over those with better navigation skills.

It remains true that GPS doesn’t help with pointing an antenna and reading signal strength. It also doesn’t help one recognize reflected signals, and doesn’t make one a good trail runner. And it supplements but doesn’t totally replace observing one’s progress and surroundings to estimate position on a map, and choosing a reasonable route to follow. GPS doesn’t eliminate the need for all skills. But in many situations it greatly reduces the importance of navigation skills.

If you don’t think that satellite position data currently reduces the importance of navigation skills, then just wait. Better algorithms and integration with additional sensor data will bring new features, making it unrealistic for anyone to be competitive without incorporating satellite navigation systems into their receivers.

The latest technology needs to be brought into ARDF equipment. But that doesn’t mean that all technology belongs in the sport. Let’s make the equipment lighter, more integrated, more rugged, less expensive, more available, and simpler to use. But let’s not diminish the fundamental skills required for the sport.

IARU Region I has already set its course toward transforming ARDF into an exercise in geocaching. That doesn’t mean that other regions must follow suit. If “AGPS” proves popular, then it can be added as a separate class of competitor, like the age and gender categories that exist today. But let’s keep traditional classic ARDF as an individual navigation sport: a sport of equal measures brains and brawn.

Satellite-based geolocation services introduce a completely new data source into the sport of ARDF. One can argue whether adding an external  navigation source is a good or a bad thing. But it will undoubted have profound effects on the sport – not all of those effects are immediately obvious.

Consider the case of taking bearings toward a transmitter signal. A bearing consists of two pieces of information: a direction and a location. Both of those information components are very important. Obviously the extent to which a bearing direction is inaccurate, the quality (usefulness) of the bearing is diminished. But the same is true if you draw that bearing as originating from the wrong location. If your position
estimation is wrong by 200 meters, your bearing might miss the fox by
200 meters even if your bearing direction is perfect.

Now consider when your bearing locations are determined by GPS: the error of the location component of your bearings will generally be less than 50 meters, and often 10m or less. You can pretty much bank on that degree of GPS position accuracy at most venues. That high degree of accuracy, derived from satellite signals emanating from far away, will be maintained consistently even if you are tired, confused, or just not very good at reading a map! Perhaps a practiced and skilled ARDF competitor can accomplish nearly the same degree of accuracy when manually drawing lines on a map using a grease pencil. But it is a near certainty that a newbie to the sport won’t be able to accomplish the same feat without GPS. But a newbie will quickly master the use of a GPS-assisted bearing-taking device, and will be taking bearings much like a pro in short order despite having mastered none of the navigation skills historically required for ARDF.

The previous paragraph illustrates two points:
1) Although technology does not eliminate all the advantage of practiced skills, it does diminish the need for orienteering skills.
2) The use of satellite navigation technology  will disproportionately improve the performance of lesser-skilled competitors; more so than skilled competitors.

That second point suggests that uneven availability of technology
amongst the lesser-skilled competitors will likely result in changes
to their finish order. That is, technology might not change who medals
in a competition, but it is likely to help those who finish farther down the finishers list move ahead of their peers who lack the technology.

If satellite-based geolocation data is to be allowed in the sport then fairness dictates that allowable technology be universally available, and that newbies and novices are not locked out of permitted technologies due to price or availability.

Want to share your ideas on the subject of smartphones and permanent Region II ARDF rules? Subscribe to the mailing list created especially for that purpose:

https://openardf.org/mailman/listinfo/iaru_region_ii_rules_and_smartphones_openardf.org

Everyone is welcome. Just keep the conversation civil.

It seems that any rewrite of IARU Region I rules to permit the use of smartphones would necessarily touch on Part B, Appendix 1, paragraph:

“T4.2 The use of satellite positioning devices is allowed provided they do not contain digital map of the terrain (“nonmapping” devices).”

This will be a sensitive issue for those competing with satellite navigation devices, and ARDF receivers incorporating them. But those who maintain that the use of satellite positioning systems is equivalent to past innovations in ARDF receiver technology and running apparel are missing the point. The fundamental difference is that the use of geolocation receivers (GPS, GLONASS, etc) introduces navigation information that is derived from a source located totally outside the ARDF course and its transmitters.

From its inception, ARDF has allowed only these sources of navigation information:

o Official Course Map
o Compass Direction
o Received Radio Signals (from course transmitters only)

Those three navigation data sources constitute the foundation of ARDF: the fundamental elements of navigation in that sport. Until recently, all other navigation data sources have been absent (if not specifically banned) from the sport of ARDF.

Region 1 has changed all that with the introduction of paragraph T4.2. That paragraph has been interpreted by some to mean that, aside from the display of digital maps of the terrain, all use of GPS data is permissible.

Satellite geolocation systems derive position information from signals emitted from orbiting satellites. Such outside-the-course information, whether displayed on top of a terrain map, used in the calculation of bearings, distance calculations, the display of followed track, or any other navigational purpose, constitutes a new navigation data source. A source that can be used to substitute for map reading and compass headings, and is available even in the absence of an active “fox” radio signal.

With the addition of paragraph T4.2 to IARU Region 1 ARDF rules the sport of ARDF is now defined by four navigation data sources:

o Official Course Map
o Compass Direction
o Received Radio Signals (from course transmitters only)
o Received Geolocation Service Signals (from satellites)

Not all innovation involves the addition of new data sources. Improvements to ARDF receiver designs to decrease their bulk, or improve their performance, still allow those receivers to pull in information only from the received course transmitter signals and nothing else. Digital compasses sense the Earth’s local magnetic field in order to derive a heading, just like mechanical compasses. Course maps displayed on video screens would add convenience, but no additional map data. Cleats on running shoes improve traction for running, but don’t add a new mode of locomotion.

Satellite navigation receivers are different.

The addition of satellite signals to the definition of ARDF might be good, bad or indifferent depending on one’s perspective. But regardless one’s opinion of the benefits, the fundamental change made to ARDF should not be ignored or glossed over. And any rewrite of paragraph T4.2 should involve the rules’ authors’ careful consideration of what data sources should be included in the sport. If the door is open to allow the use of satellite navigation signals, are there other external sources that should be added as well? Is there justification for excluding anything?

But it should be recognized that although almost all smartphones include satellite navigation hardware, ARDF-approved apps will be able to include, or exclude its use so as to adhere to the rules regardless the fate of satellite-derived navigation in the sport.

Should-Be-Asked Questions intended to help clarify issues related to smartphones and similar personal electronic devices running approved ARDF apps are presented below.

Won’t smartphones allow competitors to place phone calls, use maps with GPS, etc. to gain an unfair advantage?

Smartphone hardware does indeed provide support for cellular network access, maps, and other features that, if permitted, would radically change the nature of ARDF. But the hardware features are only accessible through software programs that provide the user access to those functions. An app that does not provide access to the cellular network, or maps, or any other prohibited functionality will prevent the user from accessing those features for as long as the app is running. Apps approved for use in ARDF would not provide access to prohibited functionality.

Won’t a competitor simply be able to close an app and make phone calls, etc.?

Yes, an app can prevent access to prohibited functions only so long as that app is running in the foreground, and maintains control over what the user can access. But approved apps would be required to record events such as the app’s closure, phone calls being answered, and any circumvention of the app such as placing it in the background. The easiest way to record such events is to create log files that reside on the smart device. Those same logs would be required to be submitted immediately after completing a course, by all competitors carrying a smart device in a competition. Failure to provide a continuous log file, or any circumvention of the app indicated in a submitted log, will result in the disqualification of the competitor.

So a competitor carrying a smart device must be required to run the same approved ARDF app during the entire time on the course, from start to finish. Failing to do so will result in disqualification.

In an emergency, a competitor could elect to close the approved app in order to place a phone call for help for him/herself or another competitor. That is an important benefit of allowing cellular-enabled devices to be used on the course. And in the event that a smartphone is used in an emergency situation, the Jury could rule to allow such use in that instance. Such emergency use should be quite rare.

Won’t analyzing all those log files require a lot of effort on the part of organizers?

Before smart devices and approved apps are permitted for use in major ARDF competitions, an automated system for log file submission and analysis should be implemented. Approved apps could automatically and wirelessly upload log files to a server (or local PC) for analysis. The server could automatically analyze all submitted log files, and notify organizers of any suspicious events contained in them. Organizers and/or the jury would only get involved if suspicious log data is found; This should be a rare event.

What about jailbroken phones, hacking, and counterfeit apps running on competitors’ devices?

The devices would not need to be approved for ARDF use, only the apps that run on them. So jailbroken phones, and side-loaded apps, are not an issue. If an approved app is run on a jailbroken phone, or has been sideloaded onto a device, it is still an approved app, and will only provide permitted functions, and will record logs containing evidence of any app circumvention.

Since it is the apps that are approved for use, measures must be put in place to authenticate the apps running on competitors’ devices. Again, the log files could be used for this purpose. Approved apps could be required to support a registration procedure at time of installation, that embeds into the app a unique public key. A unique identifying tag encrypted by the public key (a signature) would automatically be included within the log file submitted by each app-carrying competitor. If the tag in a log file decrypted by the associated private key were found not to match the tag associated with the registered app, that would indicate that an inauthentic app was used and that competitor would be disqualified.

Hacking the authentication system should be made difficult, but extreme measures need not be employed. As long as it is much harder to hack the authentication system than to sew a hidden pocket into a uniform for stashing a disallowed mapping GPS device (for instance), a cheater will choose the easier path.

That all sounds like a lot of work, isn’t it too great a burden to place on organizers and the Working Group?

Yes, the burden of implementing authentication measures, log file submission and analysis tools, and all other components of the overall support system for approved apps, should lie squarely upon those who would utilize the system: the app-carrying competitors and the app writers.

The only burdens imposed upon event organizers and regional authorities should be the creation of rules, approval of systems implemented for authenticating apps, and the adjudication of issues that might come up. That degree of support should prove small relative to the potential benefits.

Who wants to use smart devices and approved apps anyway? What would they add to the sport?

Were a blanket ban on all communication devices not in place, we would almost certainly see smart devices in use at ARDF events today. But without rules governing their use, it is not worth the effort to develop apps and a system to support them, because there is no assurance that the developed apps will ever be allowed to be used in competition.

Modern smartphones and similar devices can provide a vast array of functions relevant to ARDF. From a simple compass app providing magnetic headings, to a graphical user interface providing access to all receiver functions, satellite positioning information (if permitted), background track recording, real-time position reporting, and control point arrival registration. Almost anything imaginable within the rules can be done, including enforcing the rules themselves, with approved apps and a system to support them.

With the rise in popularity of smartphones, approved apps should lower the cost barrier for entry into the sport. Since many participants will already own the most expensive hardware component (the phone itself) little more than a receiver front-end and a suitable antenna will be required to fully participate in the sport.

Cell phone communications access, provided by the smartphones carried by competitors, can add to the sport’s safety.

Welcoming ARDF-app programmers worldwide will help bring in new sport supporters and participants.

In short, there is a lot to be gained from the use of smart devices and approved apps. But it all starts with the rules.

Who would approve ARDF apps?

App approval could be done in any number of ways. But one approach that would help focus the responsibilities on the app users and developers, would be the authorization of App Approval Authorities (for lack of a better name) who would take on the responsibility of developing a complete system.

Applicants from the community of ARDF app users and developers might be allowed to apply to a Regional ARDF Working Group for recognition as an ARDF App Approval Authority. A group so designated would have the responsibility to develop a complete app authentication system for approved ARDF apps: a system that applies to app development, validation, dissemination, and use in competition. The only real “authority” of such an Authority, would be that of defining exactly how the app approval process works under their system. The only reasons for such groups to be officially recognized by the WG, is to avoid chaos, and to afford those Authorities some standing when they request reasonable accommodation at ARDF competitions for testing their systems, etc.

An App Approval Authority would be responsible for all of the work and investment involved in designing and implementing a system to approve and authenticate ARDF apps. It would also be responsible for providing documentation to the Regional ARDF Working Group demonstrating that a proposed system works correctly, reliably, securely, and does not impose excessive demands on organizers.

What would be the approval process for a candidate ARDF app?

App approval would necessarily be a component of an authentication system. It should be the responsibility of an App Approval Authority to define an app approval process that passes muster with a Regional ARDF Working Group.

Exactly what form an app approval process takes remains to be seen, but some of the elements of the approval process might include:

1. App authors being required to certify that their apps provide users access only to functions and features allowed under the latest release of official ARDF rules.
2. Apps being required to successfully complete a validation process proving that they support log file creation, encryption and submission requirements. (Apps might be required to incorporate the binary of a custom authentication library, providing them with the ability to successfully register and submit logs.)
3. Apps would probably need to be officially submitted to an Authority for approval well ahead of their use at sanctioned events, to allow time for validation and any required rework.
4. Apps might be required to be open source, so that no hidden functionality could be concealed in them, and a wide community could examine them in detail.
5. Apps’ binaries might be compiled and submitted to app stores by an App Approval Authority, rather than by the app authors, in order to ensure the integrity of the submitted binaries.

How do the rules need to change in order to allow approved smart-device apps for ARDF?

Using the Region 1 rules (version 2017) as a baseline, the following changes to Part B Appendix 1, Section T4 should suffice:

T4.2 All personal electronic devices (including satellite positioning devices, and radio receivers or other devices with integrated navigation or communication functionality) are disallowed unless their capabilities are inherently limited to provide no navigation assistance or communications functionality except for the following:

o Short range device-to-device digital communications providing connectivity between permitted devices carried by the same competitor (e.g., Bluetooth, WiFi, or NFC data link between a receiver and a display screen.)

o Long-range digital communications providing connectivity specifically authorized by event organizers (e.g. real-time competitor position reporting over a cellular network.)

o Display of digital official competition maps provided by the event organizers, that can be used in lieu of a paper map.

o Compass direction.

o Non-graphical position information (e.g., latitude and longitude text data stored to a track file) that is unavailable to the competitor during the competition.

Any device capable of providing navigation or communication functions beyond those listed above is subject to T4.3.

T4.3 Personal electronic devices, receivers, and other devices that would otherwise be banned under the rules shall be permitted to be carried by competitors and team officials during the competition if both of the following conditions are met:

o Any device capabilities banned under the rules are not used, and are effectively disabled or unavailable at all times and in all situations where those capabilities are disallowed.

o Evidence of compliance (e.g., continuous log files) to establish that banned capabilities were not utilized must be provided in accordance with an App Authentication Procedure administered by an App Approval Authority designated by the Organizing Society, or as directed by the Organizing Society.

Note 1: the wording above is intended to maintain the ban on smart devices until App Authentication Procedures and App Approval Authorities come into existence, or an Organizing Society decides to establish their own procedures. The terms App Authentication Procedures and App Approval Authorities will also need to be defined in Part A section 1.

Note 2: the wording above is intended to allow an Organizing Society that wants to implement its own app authentication procedures for a particular event to do so. Not all competitions necessarily need to have the most stringent level of rules enforcement. An Organizing Society might choose to simply spot check logs randomly, or only if an infraction is reported or suspected.

Note 3: T4.2 above lists those functions that are allowed, rather than attempting to describe every conceivable function that might be disallowed. This approach should result in a shorter and simpler list, and forces us to consider what should be permitted on a case-by-case basis.

Note 4: Some additions to the list of permitted functions in T4.2 will probably be required in order to permit commercial “non-mapping” satellite positioning receivers as currently permitted under IARU Region 1 rules, if their use is to be permitted under Region 2 rules.

The goal of Classic ARDF is to find all the transmitters required for your age/gender category in the least-possible amount of time. Period. Full stop. End of story. If you can accomplish that feat, then you should always be pleased with your performance: only your physical limitations kept you from doing better, so you need only improve your strength and endurance.

But with five transmitters to locate, there are 120 (5!) fox-order permutations you can take on your journey from Start to Finish. Choosing which of those 120 routes to follow is key to minimizing your time.

It is tempting to assume that the route with the shortest total length will result in the shortest-possible time. But that is true only if you can run at maximum speed regardless of gradient and obstacles, and can locate transmitters with equal ease whether they are on the air, or silent. So there are at least three factors that contribute to your total time:

o Total route length (shortest is best)

o Ease of traversal (easiest running is best)

o Timing of arrival (arriving to within “striking distance” of each transmitter when it just starts its 1-minute transmit period is best)

The first two factors (total route length, and ease of traversal) are readily understood, though not always easy to gauge using just map and signal readings. The third factor (timing of arrival) is less obvious, and often overlooked in the calculation of best-possible route, but no less important when performing route-choice calculations.

To illustrate the role of timing of arrival, it can be helpful to imagine the case where total route length, and ease of traversal, play no part. Consider a perfectly flat landscape with no obstacles to avoid. Now pretend that you are the “Usain Bolt of ARDF”, and can cover the distance between any two points on the course in two minutes or less (roughly two transmit periods for a fox). Even Usain can’t do that? Then make yourself the Roman god Mercury instead.

Since all routes are equally runnable, and you can arrive at any two points in a 2-minute time interval, your only concern is to have the transmitter you are chasing be on the air at the moment you find it. You are a Roman god, but that only makes you fast, not omniscient – so the transmitter must be on-the-air in order to “sniff it out”, unless you are simply lucky and find its flag off cycle. Lucky is good too, of course, but harder to perfect.

Like all your competitors, you start the course from the Start when Fox #1 begins its transmit cycle. Feeling fresh, and with your lightning speed, you traverse the distance from Start to Fox #1, finding it in the middle of its second transmit period at minute 6, 5.5 minutes into the competition. With the bearings and signal strength readings you took during the first 5-minute transmit cycle, you have a good estimate of the approximate locations of all four remaining foxes; accurate enough that you can identify locations that would place you within a 1-minute sprint of each one.

So the question is: in what order should you attempt to find the remaining foxes? There are 24 possible permutations. Let’s examine two of them.

You’ve got 30 seconds before Fox #2 begins to transmit, so let’s examine the choice where you take it next. You head in the direction of Fox #2 and travel in that direction for 30 seconds before it begins to transmit. You use its signal to guide you as you run, but one minute later you arrive within final sprinting range of Fox #2 just as it goes off the air. Now you must wait four minutes for Fox #2 to come on the air again so you can sniff to its exact location. Suppose you find Fox #2 the next time it transmits during minute 12, at 11.5 minutes into the competition. Following the same strategy you select Fox #3 next, and with similar results you locate Fox #3 at 17.5 minutes. Fox #4 then is found at 23.5 minutes, and Fox #5 at 29.5 minutes. After a 1-minute dash to the finish your total time is 30.5 minutes. That’s good enough to beat most mere mortals, but could you have done better?

Let’s look at another route order. Suppose standing at Fox #1 at minute 6, you had instead decided to head toward Fox #3. You would have traveled for 90 seconds before Fox #3 began its second transmission at minute 8 into the competition. You would be assured of arriving to within sprinting distance of Fox #3 after traveling 120 seconds, and you still would have 30 seconds of transmit time before Fox #3 goes off the air. Chances are good (at least 50:50) that you will find Fox #3 before the end of minute 8. Suppose that you succeed, and then choose Fox #2 for your subsequent destination. You will start to travel from Fox #3 toward Fox #2 at the start of minute 9, and arrive within sprinting distance of Fox #2 by the start of minute 11, about one minute before Fox #2 comes on the air. After waiting one minute you then will locate Fox #2 during minute 12. Then you will choose Fox #5, which you are likely to take during minute 15. Then you’ll find Fox #4 at minute 19. Even if it takes you 2 minutes to dash to the Finish from Fox #4 your total time is about 20.5 minutes. By choosing more optimum timings of arrival, you succeeded in shaving 10 minutes from your time. Good enough to beat all but Neptunus Equester.

The example above illustrates the benefits of factoring in transmit timing to determine an optimum time of arrival. Minutes can be saved when choosing the route with the best timing advantage, from two or more routes that are otherwise similar in length and difficulty.