No, I’m not the type of neighbor who yells at kids “Get off of my lawn!” I am more likely to be looking up when there is a trespasser. Of course, I don’t own what’s above my house but I am rather curious about who is breaching my airspace. I usually can find out instantly thanks to one of my radio sub-hobbies.
My digital aviation logbook has included USMC Ospreys (which I’ve flown on numerous times), DoE radiation trackers, other mysterious government planes, all sorts of commercial aircraft and medical helicopters. One time I even detected then-Congressman Adam Kinzinger directly over my house near the Potomac in Virginia (I think the lawmaker was flying a million dollar Piper Meridian turboprop).
My brother Jay, an electrical engineer, on one of his visits to our house in Virginia, helped me get the original Raspberry Pi ( a single-board computer) to play nice with the receiver and the wi-fi connection.
I had some mysterious technical issues recently and replaced all the kit except for the antenna. You don’t need an MSEE degree to trouble-shoot, but it probably helps.
The receiver picks up the signals at 1090 MHz from planes and helicopters. A simple antenna for that frequency sits outside my ham shack window with a westward view. If a plane is above a decent altitude (30,000+ feet), the range is about 75 nautical miles. If I one day get the antenna on the top of my roof, I’ll have a 360° view and a much better range.
As you can see there’s plenty of information to inspect and analyze — which airline flight the plane is operating as, altitude, speed, distance from my house and the direction in which the aircraft is currently heading.
When I hear and see a low-flying aircraft I can quickly ascertain whether it’s civil, military, law enforcement or medevac.
Decades ago, for a radio news story, I went up in one of those small prop planes with a cop who was looking for pot farmers. I found out the secret, by the way, of how most basement cultivators are identified — not by aerial surveillance obviously, rather through analyzing electricity bills. If you have an average-sized house and your monthly power bill approaches that of a data center the authorities might be on to you. (I always wondered if any of my ham radio colleagues running kilowatt amplifiers for their transmitters might fall under similar suspicion).
My ADS-B ground station sends all its data via the internet to FlightAware so others can see it. In exchange, FlightAware gives me a free enterprise account that allows enhanced tracking of aircraft worldwide. That comes in handy for my news reporting when there's an aircraft emergency, hijacking or sudden geo-political tensions that prompts a military to scramble surveillance planes, bombers or fighter jets.