I found this forum, and I wonder if I can enlist an expert's help. I want to build a small radar detecting device, that would looks somewhat like a Geiger counter. The idea is for this device to detect range and direction of 3-5 other devices. These would be small units that would send a signal on various frequencies. The primary device would potentially have a delectable dial in order isolate a specific device in order to find it. The range of the devices needs to be around 300 feet. This is just a preliminary idea, but canbe adjusted depending upon what can be done and for how much. I attached a picture of what could be a good look for the primary device. The devices the main device needs to locate are not as important as long as they function and have some amount of water resistance.

Thank you!