A new toy of mine has been the Audio Intelligence Devices, Bird dog 360 Receiver. This is an old school, professional grade direction finding receiver made in the late 1980's. These were commonly used by private detectives and police departments to track suspects while driving vehicles. They came with very specific transmitter frequencies and a magnet mount transmitted that needed to be placed on the vehicle. The receiver consists of two main components.
Then it is a matter of driving around and getting used to the unit. Neither the receiver box or display nit has any way to connect it to the dash. No suction cups, Velcro, or mounting brackets are included. These really look like they would be mounted to a shelf or desktop. Small rubber feet are on the bottom of both units. The display box being so light that the ribbon cable forces it to go where the cable folds push it. I use this system with the receiver seat belted to the passenger seat and the display wedged between my windshield and dash. The red display and background lighting match perfectly with a Pontiac or BMW back light scheme.
In 2015, many people may wonder why a hardware direction finding kit is useful. Software and computers have replaced a great deal of test equipment and radio gear. Well in the case of direction finding, even the software based systems require the use of hardware antennas and some form of interface box. The fact that a computer is not required could be seen as an advantage or a fault. Computer based receivers could log the data better, but would require software updates, a computer to be booted and connected, and Microsoft licenses to be updated on occasion. For stand alone units, they just work, and do not need updates to work. Their is also no possibility of malicious code or corrupt software causing damage to the equipment. For the amateur user, the only other real option is the Ramsey electronics kits. these are small plastic kits that are for hobbyist use, they are not as rugged and do not appear to hold up well with permanent installation.
For those with the need to find and range a specific radio signal, look to used commercial gear to fill this need. As a better alternative to the hobbyist kits, this type of receiver can be found on auction sites and used radio locations. Seek out county auctions, police and fire department sales. Often times the hardware is older, but fully functional. It may only lack a manual or a cable. I have had great luck finding very well made hardware that has minimal usage time for cents on the dollar this way. You can build up your arsenal of radio gear quickly and it will last longer in the field. Good luck on the fox hunt, happy hunting.