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Results and photos of the on-foot transmitter hunting session at Topanga State Park on November 22, 2014 are now in this site. Our next session will be early in 2015, so watch for the announcement. Our sessions usually include a workshop for building measuring-tape yagi RDF antennas and offset attenuators, plus beginner and intermediate level transmitters to find. Experts are on hand to get you started with your own equipment or with loaner gear. For earliest notification of future sessions, join the southern California ARDF mailing list. If you live elsewhere, click to get contacts for other North America ARDF sessions.
Scouting's annual Jamboree-On-The-Air (JOTA) was October 17-19, 2014. JOTA is an ideal time to introduce young people to all aspects of ham radio, especially hidden transmitter hunting. Only the transmitter hider has to have a ham license! If your club included transmitter hunting in this year's JOTA, please e-mail me for possible use in an upcoming article. For more information, see the Foxhunting for Scouts page at this site.
USA has medalled in the Seventeenth ARDF World Championships, which took place near Burabay, Kazakhstan from September 6 through 13, 2014. Vadim Afonkin KB1RLI took silver in M40 category in the two-meter competition on September 8. Kazakhstan Federation of Radiosport and Radioamateur (KFRR) hosted the championships, which included formal competitions on two meters and 80 meters, plus sprints and foxoring. Each country may have up to three persons per age/gender category on its team. Team USA positions were filled based on performance in the 2013 and 2014 USA ARDF Championships. More information and links to results are in this Homing In site.
Plans are coming together for the next USA and IARU Region 2 ARDF Championships. The tentative dates are August 27-30, 2015 and the location is a beautiful 3300-acre site at elevation of 7000 feet in eastern Colorado. We expect to have final approval to use the site on these dates very soon. Mark the dates and watch for more details in this Homing In site. You can also subscribe to a mailing list for announcements as they become available. More information is here.
USA's fourteenth annual championships of on-foot direction-finding took place near Boston, Massachusetts on the first weekend of June, 2014. There were formal competitions on two meters and 80 meters on Saturday and Sunday, June 7-8, plus optional sprint and foxoring events on the two prior days. USA's ARDF Championships are open to all. Visiting competitors from outside USA are welcome. Some of USA's medal winners have been invited to compete on Team USA at the ARDF World Championships in Kazakhstan this September. Complete results and photos are in this Homing In site. If your club is interested in having a future USA Championships in your own area, here is information about hosting.
In the July 2014 issue of CQ-Plus Magazine, my Homing In column reviews three new apps for phones and tablets that greatly assist in bearing-taking and triangulation. Digital subscribers to CQ-Plus can also read my column in the May 2014 issue, which is a complete photo story of the 2013 USA and IARU Region 2 ARDF Championships in North Carolina. My next column is scheduled for the December 2014 issue. CQ Publications has combined the content of CQ-VHF Magazine, Popular Communications and Worldradio into the new CQ-Plus, a supplement to the digital edition of CQ Magazine. It can be viewed on PC, Mac, iPad, iPhone and Android. My Homing In column is scheduled to appear four times a year in CQ-Plus. I welcome your input for future articles, so please continue to send me your news of mobile and on-foot transmitter hunt activities.
The seventeenth annual CQ Worldwide Foxhunting Weekend (CQ WW FW) was May 10-11, 2014 but if your club didn't hold a hunt then, it's not too late! Start the fun now by reading the announcement at this site and my article in the March-April 2014 issue of CQ Magazine. After that, plan a mobile or on-foot hunt for a weekend in the near future. This annual event is an ideal time for ham clubs and non-club groups around the country to enjoy this fast-growing sport. For clubs that participated in this year's CQ WW FW, the next thing to do (besides planning another hunt, of course) is send the results and photos to me for the follow-up article. Get the report form here.
For three decades, international-rules radio-orienteering competitions have had two major competition days. Each participant must compete on the two-meter band and the 80-meter band. The 2012 USA and World ARDF Championships included competitions in two new events: sprints and foxoring. The sprint is a shortened form of the five-fox 80-meter ARDF run that's intended to be a demonstration for the public. Foxoring is a combination of classic orienteering and direction-finding on 80 meters. More information about these new events can be found here.
Obtain RDF equipment for two-meter hunting on foot
Attend a southern California on-foot transmitter hunt
Participate in national and world championship hunts
Learn about mobile transmitter hunting (T-Hunting) and the equipment that hunters use
Attend a southern California two-meter mobile T-hunt
Buy or build a two-meter "fox" transmitter
Learn about 80-meter transmitter hunting
The Southern California T-Hunts for Beginners page has has information about three monthly mobile hidden transmitter hunts in the Orange County area where first-timers are especially welcomed and encouraged. On two of them, there are usually some clues to help everyone eventually find the transmitter and on one, you can compare bearings with other hunters on a separate frequency. Mount some RDF gear on your vehicle and come on out!
Mobile hidden transmitter hunters have regularly prowled the streets in search of the elusive sources of unusual signals for more than four decades. Equipment has evolved, but the adventure and intrigue remain the same. Read "T-Hunting Then and Now -- From Gooney Birds to GPS" in this site for stories of classic mobile T-hunts in the Los Angeles area. Some of them, but not all, could be done again today. Then to find out what it's like nowadays, and to help get your club started in this activity, read "Transmitter Hunting, Southern California Style."
When it's your turn to hide the transmitter, what will you use? It depends on the range and duration of the hunt, as well as whether or not the transmitter must be unattended and automatic. It's important to match your foxbox and its location to the level of proficiency of the hunters. There are many options, and you can read about them in the Foxboxes for Mobile and On-foot Transmitter Hunts page in this site.
USA first attended the ARDF World Championships in 1998. The people we met and the lessons we learned helped set the foundation for our current success. Here is my classic article from CQ-VHF magazine about the first Team USA trip to Hungary. Learn how a Hungarian ham was instrumental in getting ARDF started in the Western Hemisphere. This ham became a world medal winner again in 2008.
For over ten years, I have used a special cubical quad for mobile transmitter hunting on two meters. From inside the vehicle, I can select the signal polarization. Find out why this is important, why I like this antenna and how to make one for yourself in a classic Homing In column titled "Build a Multiple-Polarization Quad."
The Agrelo DFjr Doppler RDF set has been out of production for over ten years, but there is still a great deal of interest in it. DFjr was the first inexpensive plug-and-play Doppler set designed for interface to computer mapping systems and APRS. For those who own one or are considering buying a used one, the DFjr page on this site has a downloadable manual, my 73 Magazine review, antenna system improvements, and frequently asked questions about this product.
What's "Homing In?"
Homing In refers to the process of tracking down the source of a radio or other electromagnetic signal using radio direction finding (RDF) equipment.
Homing In is also the title of my regular column on RDF that ran for 15 years in 73 Amateur Radio Today magazine, then for ten years in CQ-VHF magazine and now appears quarterly in CQ-Plus digital magazine. At this Homing In site, you will find more about these columns, plus RDF articles that I have written for other publications, including Monitoring Times, CQ VHF and QST magazines. There is also information about my comprehensive book on the subject.
Radio direction finding is used to find sources of interference to any form of wireless electronic communications, including broadcast and two-way radio, television, and telephones. It is also used to track missing or stolen cars and other property. Search and rescue workers use it to find persons in distress. Emergency Locator Transmitters in downed aircraft are tracked with RDF techniques.
Most of the information at this site pertains to RDF equipment and techniques for Amateur Radio (ham) operators. Hams use RDF to track jamming stations and stolen equipment, but more often, they use it just for fun. Hidden transmitter hunting has been done by hams for about fifty years and it is a growing activity. T-hunting refers specifically to hunts involving hams driving in RDF-equipped vehicles. A mobile T-hunt is best described as hide-and-seek for all ages with radio gear. When you set out on a T-hunt, you never know where you'll end up, and you have no idea what you're going to find. No form of ham radio contesting is more fun! Mobile T-hunting is done in cities and towns all over the USA, and elsewhere in the world. Depending on the frequency band and the nature of the hunt, the hunters use loop, yagi, quad, doppler and time-difference-of-arrival RDF antenna systems mounted on their vehicles. Click here for for general information about mobile T-hunting or click here for beginner-level T-hunts in southern California.
Mobile T-hunting is called foxhunting in some parts of the USA, but everywhere else in the world, the terms "foxhunting" and ARDF refer to another kind of RDF contest, done completely on foot in large woods and parks. It's a map-and-compass sport similar to orienteering, with about a half-dozen "fox" transmitters to find in a period of two hours or so. Someday this sport, which is also called foxtailing, fox-teering and radio-orienteering, may become an Olympic event. Meanwhile, it's a fun-filled activity for your hamfests and Scout Jamborees. Try it, and you may find yourself at the next annual national USA ARDF Championships. You might even become a member of ARDF Team USA, which has competed in five foxhunting World Championships. Click here for for general information about radio-orienteering or click here for beginner-level ARDF events in southern California.
Keep reading---you will find lots more about foxhunting, T-hunting, and other uses of RDF at this site.
What's at the Homing In Site?
Find your topic of interest below in the complete Table of Contents (or as some call it, the Site Map). Or you can Click here for the Site Search page.
Getting Started -- The basics
RDF Topics in Print -- Read all about it
Home-built RDF Projects -- Inexpensive and educational
Commercial RDF Equipment -- Getting the most from it
Follow-up and Support -- for readers of THRDFS and Homing In
Championship Radiosports -- Taking on the world
Results, stories and photos of ARDF sessions, large and small
Volunteer Opportunities -- Use your RDF skills to help researchers and protect wildlife
Spending a few minutes at this Homing In site will give you a jump-start into the world of transmitter hunting. After that, you can find out how to get involved in mobile T-hunts in your area by visiting local T-hunt/foxhunt web sites and contacting nearby Homing In Correspondents listed on the links page. You'll find manufacturers and suppliers of RDF gear there, too.
Who is KØOV?A registered professional electronic engineer and an active Amateur Radio enthusiast since age 11, Joe Moell KØOV has over 40 years of experience designing radio-frequency circuits and systems for broadcast, communications, and radar, ranging from near-DC through microwave frequencies. He has designed new devices for radio direction finding and has written about RDF and other topics for almost every ham radio publication in the USA. In February 1998, he was appointed by the American Radio Relay League (ARRL) as the USA's first ARDF Coordinator, to promote international-style foxhunting and to organize Team USA for international ARDF competitions. He also conducts the annual CQ Worldwide Foxhunting Weekend.
Joe collaborated with Tom Curlee WB6UZZ to write TRANSMITTER HUNTING---Radio Direction Finding Simplified, a comprehensive text on RDF, and has written over 230 published articles on the subject, including his monthly Homing In columns that ran for 15 years in 73 Amateur Radio Today magazine, then for ten years in CQ-VHF magazine and now appears quarterly in CQ-Plus digital magazine. As a Technical Advisor to ARRL Headquarters, he authored a new chapter on RDF for The ARRL Handbook and has made more than 100 presentations on transmitter hunting to clubs, conventions, classes and seminars. As time permits, he is available for private engineering consulting.
Joe and April (WA6OPS) Moell are graduates of the University of Nebraska. They have served as Course Marshals and Jurors at international foxhunting championships. When not participating in transmitter hunts or writing about it, they teach ham radio licensing courses and help support the emergency communications needs of the hospitals in their county.
Although not about RDF, another great ham place to browse is the Hospital Disaster Support Communications System (HDSCS) site. There you will learn how volunteer Amateur Radio operators can be an important backup communications resource for hospitals, if the hams are well organized and trained. The eighty members of the HDSCS in Orange County, California have served over 35 hospitals in over 115 communications emergencies during the past 30 years. We have rapidly responded following earthquakes, wildfires, floods, power outages and internal switchboard failures. If you think that your local ARES® or RACES group is presently serving all of the disaster communications needs of your community, you may consider taking on a new mission after seeing this site.
Surfing suggestion: For a quick start into the world of RDF and mobile hidden transmitter hunting, jump to Let's Go T-Hunting.
Amateur Radio Direction Finding Web Ring
This site is owned by Joe KØOV .
A great way to track down ARDF and Fox Hunting sites.
Want to join the ARDF Web Ring?
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Please note that this Web site is built and maintained independently by Joe Moell. It is not sponsored by or affiliated with CQ Publications, 73 Amateur Radio Today, Wayne Green Enterprises, TAB/McGraw-Hill, ARRL, or any other commercial or non-commercial entity. All content is protected by applicable intellectual property laws.
Entire site Copyright © 1996-2014 Joseph D. Moell. Text, photos and original graphics may not be served or reproduced elsewhere without permission.
PO Box 2508
Fullerton, CA 92837
This page updated 25 November 2014