Here in the United States, it’s the 4th of July. This normally means fireworks, though this year many are canceled due to the pandemic. But if you have them in your area and you are wondering how high they are, you can use this handy Altitude-Distance Finder. These were handed out to all Ground Observer Corps observers and came in a few varieties, calibrated to type of aircraft. They’re about the size of a credit card, so you could carry it in your wallet or purse and always be ready when you heard the sounds of unknown aircraft.
2 thoughts on “What’s Your Altitude?”
I remember having one in 1959, which was the last year of the GOC. It was very easy to use. I wish I could get my hands on one now.
You can sometimes find them on eBay, which is where I found mine. They pop up there from time to time.