Probably best by just being familiar sortof like how do you know that car is a Ford, Dodge Chebby.
Array Solutions has good towers These are easily spotted by the owner walking with a limp after the walletectomy.
Seriously though they make/offer great products but tend to be a bit more on the spendier side. But for towers, you get what you pay for as in everything else but if your tower collapses the consequences are a tad more extreme.
One of the Rohn distributors Rohn towers are easily decernable by the amount of spiderwebbing holding it up. If it's being held up by a building it's more than likely a 20, a lot of wires a 25, several wires, many wires, a couple of wires, no wires etc. etc. etc.
There is also Universal tower which makes a angle iron type tower that strongly resembles an Erector Set.
Each tower generally has a standout design or appearance trait that makes them unique. This will just come after time of staring at them. I've been doing a lot of staring lately.
I'm kind of partial to this one.
Not only is it free standing but the entire 198 feet rotates.
