Introducing PRSD: A New Radio Direction Finding Challenge Premiering in January 2027

What happens when you take away the long drive, the cross-country navigation, and the race through the woods—and concentrate on the radio signals themselves?

You get Precision Radio Signal Detection, or PRSD, a new Radio Direction Finding event developed by Rez Johnson (K1REZ) through the Mississippi Radio Direction Finding Association (MSRDF).

The world premiere of PRSD is planned for January 2027, introducing a challenge built around careful listening, precise antenna work, and the ability to distinguish an active transmitter from a nearby decoy.

Why I Founded PRSD

By Rez Johnson, K1REZ

I wanted to create an event that concentrates on the technical skills that form the foundation of Radio Direction Finding—detecting, identifying, and isolating signal sources—rather than on orienteering or navigation. These same skills help radio operators locate sources of interference (QRM) and distinguish them from atmospheric noise (QRN).

Traditional transmitter hunts offer many enjoyable challenges. Depending on the event, you may need to drive, navigate with a map, walk considerable distances, or move quickly between transmitters. Those activities are fun and have their place, but I wanted an additional format where the radio work itself takes center stage.

PRSD gives participants an opportunity to practice detecting, identifying, and isolating signals within a very small area. Success depends on how effectively you use your receiver and antenna, interpret what you hear, and determine which object is actually transmitting.

I also wanted to broaden opportunities for participation. An event that does not depend on long walks, driving, or running can welcome people who might find other formats difficult to attempt. Accessibility—including opportunities for blind and low-vision participants—is part of the purpose behind PRSD.

A Small Area with a Big Challenge

A PRSD Field Exercise can take place in a small park, a yard, a tennis court, around the perimeter of a small building, or even inside a gymnasium.

Within that area, participants encounter 30 small enclosures called pods. Six contain active transmitters; the remaining 24 are decoys.

Finding a pod is only the beginning. The challenge is determining whether it is the source of the signal you are tracking.

A decoy may be close to a real transmitter—potentially within about a foot. At that distance, simply finding the strongest general area is not enough. You must work carefully to separate the actual source from the objects around it.

Different Signals, Power Levels, and Polarizations

PRSD has standardized on the newly developed PicoFox transmitter by AI6YM. This compact transmitter plays recorded audio—including voice, tones, and Morse code—at power levels ranging from 0.1 to 65 milliwatts, allowing organizers to vary both the signal content and output power of each transmitter. Participants may encounter a variety of power levels and both vertical and horizontal antenna polarizations.

Those differences create opportunities to practice several related skills:

  • Recognizing and following a particular signal.
  • Reducing receiver sensitivity as the signal becomes stronger.
  • Using antenna direction and position to isolate a source.
  • Evaluating antenna polarization.
  • Assessing transmitter power levels.
  • Distinguishing active transmitters from nearby decoys.

A signal that sounds strong does not automatically identify the nearest pod as the transmitter. PRSD asks participants to test their conclusions before recording an answer.

Precision Is the Goal

The basic scoring principle is straightforward: correct identifications minus incorrect identifications.

Accuracy is essential. Guessing at every pod can work against you.

Ties are broken by the number of correct polarization identifications, followed by correct power-level identifications.

There is no time limit, and speed plays no role in scoring. Participants may take all the time they need to complete their objectives.

PRSD rewards careful observation, a methodical approach, and precise identification of signal sources.

Equipment You Can Learn to Use

PRSD can be approached with a handheld radio with a useful signal-strength indicator, a directional antenna, and an attenuator.

A homemade tape-measure Yagi is often a hunter’s first direction-finding antenna. AI6YM’s Minimum Viable Yagi is a kit that includes the components needed to build one, apart from the PVC pipe, which can be purchased at a hardware store.

A dedicated direction-finding receiver, such as an MK Sniffer, if you can find one, or the new FoxSniffer by AI6YM, paired with a suitable antenna, offers another approach that some hunters prefer.

The most valuable tool is familiarity with your equipment. How does the receiver respond as you approach a source? How much attenuation do you need? What changes when you rotate the antenna or alter its position?

PRSD provides a focused setting for exploring those questions and developing repeatable techniques.

Skills Beyond the Field Exercise

The ability to isolate a signal has uses beyond finding a hidden transmitter for recreation.

Amateur radio operators sometimes need to investigate interference or distinguish one source from several possibilities. PRSD offers practice in the habits that support that work: patient observation, controlled changes, careful listening, and checking an apparent answer.

It provides an opportunity to build confidence with your equipment while enjoying a new challenge.

The World Premiere: January 2027

MSRDF is preparing to introduce PRSD to its first participants in January 2027 with the first Precision Radio Signal Detection World Championship.

The premiere will offer an opportunity to experience a new event built around a simple question:

Can you identify exactly which object is transmitting?

Watch MSRDF.com and Hunt Manager for the premiere’s date, location, registration information, equipment guidance, and event rules.

Whether you are new to Radio Direction Finding or already enjoy tracking difficult signals, PRSD offers another way to put your skills to work—one carefully identified source at a time.

Useful Links and Equipment Resources

The following resources offer antenna-building instructions and equipment options to explore for PRSD and other transmitter hunts:

When choosing equipment, check its frequency coverage and whether additional components, such as an attenuator, cables, or a separate receiver, are needed.