RE: Save $20.66 on Speed gun HK buddy code
The bigger problem is how close you need to be to get a reading with the cheaper guns.
You could mount it on a tripod and still miss it from 15' away 8 times out of 10 at those speeds.
If finding out how fast a 40 mph plane interests you, this is the gun. However after you get near the 100 mph range your options slim down to a more expensive gun for safety reasons foremost. Accuracy is a whole nother discussion.
We use a Stalker Pro with very good success. We have had two of them get the same reading and paired it with a How Fast unit, all pretty much the same give or take 1mph.