Whoah,  am gonna follow this thread.

My wife is on my case to get a tracker for her lab, cus she thinks the coyoties are gonna eat her after i kick her but outside to do her nightly duties.

There are very few tracking systems that will generate signals powerful enough to carry long distances through foliage and rocks.  Any transmitting frequencies with short-enough antenna lengths will be direct line-of-sight, and a dog collar with anything more than a watt of transmit power will require a large battery, and of course, be emitting near-microwave energy within inches of the animal's brain stem and eyes.

The 'professional' way, is to use a low-power transmitting beacon, and a hand-held directional antenna to 'sweep' an area for a beacon.  Then use the direction and intensity to get a good idea of where to look.

When radiolocating crashed airplanes, or hunting out hidden transmitters or noise sources, we use multiple points of detection, with vector and strength to multi-point triangulate a signal... techniques proven since WW1... but with higher frequencies, the recieve antennas get much more compact, and can be built with much higher forward gain, and much greater null suppression... meaning, they're more sensitive in the pointed direction, and less susceptible to noise coming in from any other angle.

HAMS refer to it as "Fox-Hunting" (if they're moving)... or "Hidden Transmitter Hunting (if they're stationary). we use it to find sources of stray noise, to pinpoint damaged radio systems causing out-of-band interference, to locate illegal operators, and to track operations of criminals who aren't bright enough to know that the world CAN hear them.

You don't need any sort of license to make, own, or operate a radiolocation 'kit'... and it's not hard to make.  A receiver sensitive enough, and selective enough to HEAR the frequency you wanna listen on, and an appropriately made 'fox hunting' antenna... with a short connection cable to the receiver.  A good-quality handheld scanner, a pair of earphones, and the antenna, a st**dy pair of hiking boots, a map, pencil, and a compass is a good start.  An inline attenuator (to reduce signal strength) is necessary once you get close, as the signal will be so strong that the antenna will not effectively 'null' out a direction, but in dog-tracking, once you're that close, you'll probably (well, hopefully) hear him diggin' in the shrubbery.

Here's a good basic look:

https://www.youtube.com/watch?v=eQSiTqH9Dzw" rel="nofollow - https://www.youtube.com/watch?v=eQSiTqH9Dzw

If money is no object, I've heard these work well. 

https://buy.garmin.com/en-US/US/outdoor_recreation/sporting_dogs/c12520-c12522-p1.html

http://https://buy.garmin.com/en-US/US/outdoor_recreation/sporting_dogs/c12520-c12522-p1.html" rel="nofollow - https://buy.garmin.com/en-US/US/outdoor_recreation/sporting_dogs/c12520-c12522-p1.html

The coon hunters that have them love them.  I think the neighbors will do up to 6 dogs at once.  They have so many options now that you almost need someone to help you figure out what you need.  I believe I read that they can do up to 20 dogs for something like 10 miles.  LOL  Would have came in handy years ago when the neighbor and I were on a 3 mile no road creek and old "Ace" was going back and forth as we were going back and forth the opposite direction, he failed to tree and loading up and leaving at 11 o'clock turned into 2:30am.  Coonless to boot!