If you don’t want to invest in an expensive radar gun, there is now a very convenient device that do the same for less money, but especially that will fit in your pocket, so that you can bring with you all the time. It has been made possible by using a much smaller, flat antenna to create the same type of signal that the horn creates in a radar gun.
I bought one for me few months ago. My objective is to have a means to measure the speed of my sailplanes when DSing.
The Pocket Radar has the size à a cell phone, and is able to measure the speed of moving objects from 11 to 600 km/h. It uses 2 standard AAA type batteries and comes with Alkaline batteries included. It comes in a very nice box that will protect it during transport.
Its accuracy is about +/- 2 km/h. If you point the radar at an object moving sideways, you won’t measure anything. This is what we usually call the Cosine error. Just remember some trigonometry when you where at school and you will quickly understand. Few figures: Within 8 degrees of angle from the moving line of the object you measure, the accuracy is about 1%, at 18 degrees it is about 5% of error, and it goes up to 30% of error with 45 degreed of angle.
The Pocket Radar is pretty easy to use: Hold the radar in your hand like a cell phone camera and simply press and release the big red button on the front of the Pocket Radar while pointing the moving object. When releasing the button, the measure will appear on the screen. If you do not release the big red button, the radar will continue to send out repeating small pulses and displaying a measure approximately every second.
You can configure the Pocket Radar with different speed units: MPH (Miles per hour), KPH(Kilometers per hour), FPS (Feet per second) and MPS (Meters per second).
To do so, just press and hold the black RECALL button. While holding the RECALL button down, press and release the big red button. Now release the RECALL button. The current selected units should blink (at the bottom of the display). Then each time you press and release the big red button, the units will advance to the next possible state (miles per hour, kilometers per hour, feet per second, meters per second).
Press and release the big red button until you see the units that you want to use blinking on the display. They will continue to cycle through each time you press the big red button. Finally, press and release the RECALL button and you will lock in the units displayed on the screen.
The Pocket Radar can store 10 measurements that you can scroll using the black “RECALL“ button.
2 Alkaline AAA batteries can provide up to 10,000 speed measurements which is not bad. The battery indicator on the LCD display will help you determine when to replace the batteries.
According to the manufacturer, the Pocket Radar can spot the speed of a car from about a 800 meters away or the speed of a baseball from up to 36 meters away.
I found the Pocket Radar to work pretty well for sailplanes. After a long dive, or while DSing, it always give a measurement. It is very seldom when it doesn’t display something.
More than that, as soon as I exit my Pocket Radar on the slope, everybody wanted to play, asking for a speed measurement of their plane.
You will see on this short video how easy it is to use the Pocket Radar:
In conclusion, the Pocket Radar is very nice device, that will cover most or our use. Of course if you are targeting the DS world record, then you will need another radar gun, factory modified to go higher than the 700 Km/h achieved today. For other pilots, the Pocket Radar give you a good progression margin before to hit its limit.
Manufacturer website: http://pocketradar.com/
Price: ~ 200$ USD