More About T-Hunts



This page describes the details of an organized T-hunt, such as one that might be sponsored by a club. Mobile hunts ( using vehicles ) are described here, as well as pedestrian hunts. For people considering the creation of a club-sponsored T-hunt, this page should provide some useful guidelines.

A successful T-hunt requires some forethought, and a few important principles ( in the hunt rules ) can make all the difference between an event that people will want to join, or an event that is so discouraging that people will only attend once, or not at all. Ultimately, T-hunts must be FUN, or they simply will not succeed.


The Mount Wilson T-hunts of the 1970ís

I ( Bob Simmons ) used to participate in some very successful ( high-attendance ) hunts in Los Angeles, sponsored by the Mount Wilson Repeater Association. These hunts had some unique rules that strongly encouraged participation, especially by new hunters. The hunts were intended to develope skills for tracking down jammers, but they were also a lot of fun. A description of those hunts follows :

The hunts were always conducted on a weekend afternoon, ( once a month ) which was chosen to not conflict with other ( local ) social events, scheduled at the same time. Generally this was the last Sunday afternoon of each month, but sometimes was changed, for convenience.

The hunts were limited to the Los Angeles county, ( county lines were the boundaries ) and they were furthermore limited to 4 hours of duration, beginning at 2 p.m. Hunts were followed by a modest dinner at some local restaraunt or pizza parlor, near the site of the hidden T. Many tall stories about the hunt occurred at these dinners, and people often compared notes about equipment and techniques.


The Appeal of the Mount Wilson Hunts

One of the cardinal reason for the success of these hunts ( I believe ) was the fact that ever participant was ( more or less ) "guaranteed" to succeed in finding the hidden T... nothing is more frustrating that driving for hours and failing to find the hidden T in a hunt... not everyone can win, but dismal failure will usually kill any further ambitions, especially for novice hunters.

To achieve this "guaranteed success", the hidden T would transmit more often ( and for longer intervals ) as the hunt progressed, and would also announce "hints" and "tips" about where the transmitter was hidden. These hints would begin after the first hour or so of the hunt. They were pretty vague at the start, but became progressively more specific, so that ( eventually ) almost anyone who could read a map could find the transmitter. Anyone who still couldnít find it ( by end of hunt ) was "talked in" to the TX site.

There were two different ways to win the hunt, ( described later ) and the winners were given the right to become the "hidden T" in the next hunt... which often is more fun than winning the hunt itself. The winners ( when they became the hidden T in the following month ) had to provide modest refreshments ( water and / or soft drinks ) for hunters who found the hidden T, since they might have to wait there for a couple of hours, until the hunt ended.


The Repeater Channel Used for Hunting

The hidden TX was operated on the input frequency of the Mount Wilson repeater, and one of the rules required that the repeater must "key up" and repeat the signal, clearly. This reduced the possible search area to the coverage area of the repeater itself, but it also had other advantages.

For one thing, anyone could tell when the hidden T was actually transmitting by listening to the repeater output channel, while simultaneously hunting for signals on the input channel. Therefore, no time was wasted wondering if the hidden T was actually on the air, ( but too weak to be heard on the input ) or if it simply wasnít transmitting at that moment... listening to the repeater output would answer this question.

Another advantage involved spectators not participating in the hunt, ( but listening to the hunt progress ) as well as any potential jammers listening to the channel... by conducting the hunt on the repeater channel, the entire progress of the hunt was ( effectively ) "broadcast" for all to hear, including people considering future participation. ( or future jamming ) The hunt proved that the channel was populated by operators with T-hunting skills and equipment, that were willing to hunt down a signal.

I have recieved anecdotal reports ( from PicoDopp users ) that these organized "recreational" hunts caused "jammer activity" to drop significantly, in a given area.... and it makes perfect sense.


The Starting Points

For the Mount Wilson hunts, the hunters could begin wherever they desired... there was no specific starting point for the hunt. This is a more realistic way to conduct a hunt, if the hunting skills might eventually be used to track down jammers... in the case of hunting down jammers, the hunters will ( no doubt ) be scattered across a wide area whenever jamming begins, so it is better to incorporate that fact into the regular ( sponsored ) hunts, to make them more realistic.

There were two ways to win the hunt. One way to win the hunt was to report the most accurate beam heading, at the start of the hunt. Since hunters could begin wherever they pleased, there was usually a wide variety of beam readings that were reported ( from widely separated loations ) at the start of each hunt. About Ĺ hour before the hunt began, a "roll call" would be conducted to identify the hunt participants, and their exact locations. Generally, hunters would pick a prominant location with a clear view of the Los Angeles basin, hopefully near a freeway onramp, to allow a quick getaway once the hunt began in earnest.

At the appointed time, the hidden T would come on the channel, announce their identity, and remain on the air for 60 seconds while hunters would take their readings. The readings were then reported ( through the repeater ) for all to hear, and for all to use by plotting them on a map... this ( usually ) narrowed down the hunt area significantly. The bearings were also plotted by the operator of the hidden T, to identify the best beam reading, ( smallest error ) but the winner was not not revealed until the end of the hunt.

Winning the hunt by reporting the best beam reading encourages participation by people who donít want to participate ( or who cannot participate ) in the vehicular part of hunt, including those with physical disabilities, or with little or no equipment suitable for mobile hunts. The beam readings also revealed the powerful virtue of working together as a team, at least at the very the start of the hunt. Signal strength reports ( from the various locations ) were often "volunteered" as well. After the beam readings were reported, the co-operation ended, and the competition began.


Hunt Handicap Rules

The 2nd way to win the hunt was to arrive at the hidden T location with the best time, adjusted with a handicap system to allow for the various distances that each team had to travel, to find the T. Individual hunters were allowed, but most people hunted in teams of 2, for road safety reasons. Each team was required to report its location before the start of the hunt, regardless of whether or not they also reported a beam reading.

The distance handicaps were calculated using a coefficient of "X minutes per mile" of distance from the starting points to the hidden T, ( straight line distance ) and the resulting minutes were subtracted from the arrival time of each hunter. For example, a hunter that began 20 miles from the hidden T and required 90 minutes to actually find the T would be scored for less than 90 minutes, due to the distance traveled. If the handicap was 2 minutes per mile, ( average speed = 30 MPH ) then the adjusted time would be 90 - ( 2 x 20 ) = 50 minutes.

The handicap system included a 2nd factor, based on the number of times ( during the past year ) that each hunter had previously won the hunt. This ensured that some really "hot" hunters would not dominate the hunt, ( every month ) making it impossible for others to win. This pre-win handicap was heavily weighted in favor of newcomers, to encourage their participation. I donít recall the exact numbers used, but first-time hunters had better than a 50% chance of winning the first hunt they attended. ( so they became the hidden T the next month )

Like the miles traveled, the pre-win handicap numbers were expressed in minutes, and subtracted from the actual hidden T arrival times. For someone who had never won in the past 12 months, the handicap might be 60 minutes, or more. For someone with one "win" in the prior 12 months, the handicap might be 30 minutes, 20 minutes for 2 prior wins, 15 minutes for 3 prior wins, etc.


Additional Hunt Rules

There were other rules, but basically pretty simple... the T had to be stationary, hidden somewhere within 100 feet of a vehicle road, and readily accessible by pedestrians without breaking any laws. It was required to transmit for at least 60 seconds at time intervals not exceeding 10 minutes in the 1st and 2nd hour, 5 minutes in the 3nd hour, and furthermore whenever a transmission was requested by a hunter, after that time. ( if I recall properly ... itís been a while )

The hidden T site had to be constantly manned by a member of the hiding team, within maybe 50 feet of the hidden T, and clearly visible from the Tís location, at all times. The hidden T operator had to be equipped to record the arrival times of all hunters who actually found the hidden T. ( finding the operator was not enough... the actual T had to be found )


Hunting Memories

There may have been other rules, I canít recall them, but I remember these hunts were a LOT of fun, especially the task of finding a new ( oddball ) hiding place for the next hunt, after winning.

I once hid with my teammate beneath a public pier in the industrial part of Los Angeles harbor, and I recall hunters frantically running onto the pier, ( a few feet above our heads ) and shouting "theyíve gotta be here"... but they never looked under the pier. Gazing across the open channel of water to the harbor on the far side, they eventually guessed we were there, and promptly took off. We were eventually found by other hunters, and it was ( as usual ) a lot of fun for all.

Another time we hid under a railroad trestle next to a public bike path by a flood control channel. The path was paved and wide enough for a vehicle, ( as required for the rules ) although the public was only allowed to ride bicycles there. Since it was accessible to the public, ( but not in a vehicle ) and within 100 feet of a vehicle road, it strictly obeyed the rules of the hunt, but it exploited this subtle "loophole" in the rules. ( which were subsequenty corrected to prevent this sort of foolishness again )

No-one found us that day, and we had to talk the whole crowd of hunters into the location after the hunt terminated. ( a walk of about 1/4 mile from the nearest bike path entry point ) Prior to that, they had invaded the most exclusive country club in Long Beach, ( about 200 yard away ) waving Yagis around all over the golf course, running from green to green, and generally acting like a horde of deranged madmen.

The SquawkBox and MicroHunt transmitters ( sold on this website ) have developed their own unique and enviable reputations in many T-hunts, due to their very small size, which allows easy concealment. Iíve heard many interesting stories about the very creative hiding places people have found for them, and how they were concealed.

One was wrapped in green leaves and used green wire for a simple dipole antenna, hidden in a bush. Another was installed in a piece of beach driftwood, bandsawed in half to allow installation, and re-assembled with glue. Theyíve been put inside paper macheí rocks, womenís bras ( some co-operation is required ) and duct taped under a seat on a public bus. ( ever tried to board a bus carrying a 3 element, 2 meter Yagi ? )

One fellow with a SquawkBox used a Polaroid battery from a filmpack, which is flat and only 1/8 inch thick. He taped the whole thing to a plastic fence in an open field, ( "ranch rail" ) using plastic tape of identical color, so it was virtually invisible, even within an armlength. Not many folks knew about SquawkBox transmitters at that time, so everyone was looking for a big box with a radio, timer, recorder, battery etc. but they ended up in an open pasture, pointing their Yagis at a fence rail, and scratching their heads.


Precautions and Warnings

I think a good part of the appeal of these hunts is the fact that they allow people to indulge in some very primitive emotions that are not usually tolerated in a modern soceity... The deep, primal hunting emotions that our ancient ancesters ( no doubt ) cultivated to a high degree ( for reasons of survival ) have become obsolete and even dangerous, in todayís world. T-hunts allow people to experience those emotions in an activity that otherwise is quite innocent and harmless. Look at the addictive success of violent video games, for other examples.

Even so, limits must be imposed. People have been injured and even killed on these kinds of hunts, due to reckless driving and excessive speeds. Some hunts are therefore based entirely on mileage driven, instead of arrival times, to defeat this dangerous and bloodthirsty aspect of the hunt. A comprimise might be to penalize arrivals that clearly would require illegal speeds, or disqualify them completely.

Whatever measures are taken to deal with this, it is imporant to realize there will always be some people out there who think that T-hunting is a license to fly, so think about ways to clip their wings, while developing the rules for your own hunt.

The results of each hunt can be posted to the club website, for public interest, and also to provide a public record of winners, for handicap calculation reasons. Anecdotal stories about the hunt are also common, ( and interesting ) and photos of the contestants and equipment are always worthwhile and interesting.

Pedestrian Hunts

Pedestrian hunts have been highly formalized in Europe, ( ARDF hunts ) where such hunts are conducted on an organized basis, involving national and international competitions. There are other websites that address these hunts in far greater detail than I can provide here, and those desiring such information ( about ARDF rules and competition ) should look elsewhere.

Despite that disclaimer, there are some appealing things about pedestrian hunts that are intriguing, and might appeal to some amateur communities in the United States. ( especially if the strict ARDF rules are relaxed ) They tend to attract a younger crowd of competitors, since their is an athletic element to the hunt... runners and joggers ( i.e. those physically fit ) have a clear advantage over couch potatoes.

The equipment must ( obviously ) be completely portable, and as light as possible. Physical ability is not paramount, however... some degree of strategy, and maybe a bit of luck, are also involved. Detailed knowledge of the behavior of the DF equipment is often a distinct advantage, also.

Pedestrian hunts are generally conducted in a large public park, ( 1 or 2 square miles ) preferrably thick with undergrowth and foliage to help conceal the hunters from each other, and to conceal the transmitters. Multiple foot trails are preferred, although cross-country travel is allowed. Flexible "tape measure" Yagis are preferred for these hunts, due to their light weight and ability to survive abuse.

Urban hunts are also possible, in large parks and even in congested civic centers, if "low mutual visibility" of the hunters can be achieved. Such hunts might be more convenient for many clubs, and easier to organize and conduct. College campuses are another good candidate, if the campus police are notified well in advance.

In the spirit of international ARDF, multiple transmitters are usually employed, all operating on the same radio channel, and transmitting in a fixed sequence, one after another, to prevent interference. All transmitters operate within range of each otherís signals, so precise timing is essential to prevent interference. The MicroHunt T-hunt transmitters ( available on this website ) were created for exactly this kind of hunt... Their simplicity, small size and low cost allows several to be purchased for a modest sum, and they employ crystal timing that drifts much less than 1 second per hour.

Typically each transmitter operates for 60 seconds, ( sending a simple CW message to identify it ) then remains silent until itís assigned time ( in the sequence ) comes up again. Hunts typically employ 3 to 5 transmitters, which can be sought in any order the hunter desires. One of the transmitters is always on the air, so constant hunting is possible.

Each operator must choose which particular TX to seek next, so some strategy and judgement ( which one is closest ? ) is involved. Each TX site can be manned or unmanned with a control operator. If unmanned, a hand-operated "card punch" is usually located at each TX site, and used to punch a card carried by each contestant, ( with a unique shape to the punch hole ) to prove the TX was actually found. A distinct rubber stamp ( and ink pad ) can also be used, such as adjustable rubber "date stamps", that can be manually set to stamp any date desired. ( use different dates for each TX and for each hunt )

Contestants are started at staggered times ( 5 minutes between each start ) to ensure each hunter is acting ( as much as possible ) independantly of the others. ( "follow the leader" is not allowed ) Once all transmitters are found, the hunters return to the starting point and their arrival times noted. The winner is the one with the best time. Handicaps can be added to the rules if one or more transmitters are never found by a hunter.

Electronic accessories such as GPS units may ( or may not ) be allowed by the rules. Adding GPS units to these hunts would also allow someone to win based on the minimum distance traveled, since most portable GPS units have ( resettable ) "trip logs" that can keep track of distances traveled.

Hunts like this can be a lot of fun, but also very educational about the behavior of radio waves "in the wild", where reflections, hot spots and dead zones are a common fact of life. Hunting multiple transmitters simultaneously allows a great deal of practical experience to be obtained in a short time, since each transmitter will exhibit itís own "peculiarities" due to reflecting and obscuring bodies and structures.


Terminal Phase of a Hunt

Pedestrian hunts can yield valuable information about hunting jammers as well, including "accidental" jammers. ( stuck PTT buttons, etc. ) If the hunt rules stipulate a 100 foot proximity to a public road, ( for vehicular hunts ) then hunters can simply "look around" when they arrive, and the transmitter can be found in a few minutes, with no portable DF equipment at all. Otherwise, the last 100 yards ( or more ) of a hunt might very well require some portable DF equipment and skills.

Pedestrian hunts are often necessary ( in the final phase ) in "real world" hunts due to the circumstances of the hunt itself...."False alarm" ELT signals from aircraft parked at an airport ( and aboard vessels docked in a harbor ) rarely allow a "direct approach" to the transmitter with a motor vehicle... such vehicles would not be allowed on an airfield, ( for security and insurance reasons ) and many vessels are located among hundreds of slips, or at the end of dock fingers in marinas, possibly hundreds of feet from the nearest road.

Multiple aircraft are commonly parked next to each other on an airfield ( and multiple vessels are commonly docked adjacent to each other in a marina ) so identifying which exact aircraft or vessel contains the radio source requires "up close" DF observations. Portable equipment ( and tactics and experience ) are the only answer, in these cases. In some cases, the signals can be silenced ( or greatly reduced ) by wrapping the antenna in tinfoil and duct-taping it in place. A conspicuous note ( left for the aircraft or vessel owner ) completes the hunt, if the owner cannot be directly contacted or identified.