BMG Engineering, Inc. must warn anyone wishing to deal with malicious interference that the perpetrators may be dangerous! We cannot be responsible for your safety. To get you started on thinking about safety, please read the article on Personal Safety! Remember, YOU are responsible for your own safety!
I wish to pass on some thoughts and cautions. Remember, these are only suggestions. You and your teams must remember that it is you who are responsible for your own decisions and actions. We urge that you work closely with the local FCC office, police (try to find an officer who is a HAM), and your own lawyer. Start this process before beginning to hunt. Try to have the police with you when you close in for the catch. If several teams are hunting at the same time, the first to "Locate" should call in the other teams before the actual closing in is started, so that all teams arrive at the same time. This is for safety.
Call a local airport and ask them what the local magnetic bearing correction factor is, and how to use it. (Here in Southern California the correction factor is about 14.7 degrees!)
It can be very useful to do a little detective work before doing any RDF work. Determine the address of your suspect(s). Drive past, attempting to identify any automobiles that might be used in mobile jamming operations. Do not trespass! Look for mounted antennas which could be used for transmission on your system's frequency. Take down the license plate number(s) and vehicle description(s). If possible, verify the ownership of the vehicles. In California any citizen can obtain ownership information for a license plate number from the state Department of Motor Vehicles. Check this out in in your state. If possible, provide each hunter with the above vehicle description, license number, and a picture or description of the prime suspect. Do a little "Jammer-think." Where would be good locations to jam from? Some place which is close to the repeater itself, public access, and with a direct line-of-sight to the repeater. The site should also provide the jammer with good visibility of roads over which a transmitter hunter would have to drive to reach the site. If later triangulation shows that one of these "unapproachable" sites is being used, do not attempt to drive in upon the site at that time with the RDF antenna mounted on the hunting vehicle. Stop, remove and stow the antenna, and then drive to the site, looking for the suspect's vehicle. Also, you might stake out (out-of-sight) the suspected location at another time when jamming is likely.
Use Field Strength Meters. These can be used to detect the very strong signal as the hunter drives past a transmitter. This allows verifying the suspect is transmitting without having a conspicuous RDF antenna on the hunting vehicle.
Its a good idea to have two or more people in each hunting team. This provides a limited degree of safety. Multiple witnesses are much preferred. The passenger could be equipped with a camera to photograph the suspect and car as the team locates him. This might be useful in any sort of court proceeding. Try to take the pictures as you approach, or otherwise without the jammers knowledge - he could become violent! Be sure to log the exact situation and caught vehicles license number at the scene of the crime. Talk with your local FCC agents on how to proceed. Take NO action against the person at the time he is caught!!!
After the suspect is caught and identified, the FCC and yourselves may be able to work out an approach to the jamming. Our local office has issued warning letters to jammers, which sometimes is all that is needed. Sometimes simply being caught is sufficient to stop the jamming. It may be that the best approach would be to use your lawyer, threatening that immediate civil action will be taken in a court of law.
See the articles: Spiral-In Hunting Technique -- Personal Safety -- Triangulation.
George R. Andrews (Russ, K6BMG) BMG Engineering, Inc. 9935 Garibaldi Avenue Temple City, CA 91780, USA Voice: 1(626)285-6963 FAX: 1(626)285-1684 (24 Hour, automatic) America OnLine: Grandrews Web: http://members.aol.com/bmgenginc (31 Jan 1996)
Send E-mail to grandrews@aol.com.
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