Hi Mike,
I have had a few of the 'older / original' radar detectors that sense the actual radar thats emitted from the camera and have found them to be lame at best. Often not picking them up (obviously, the camera may not have been active at the time) or not until you are literally on top of them.
The problem with them is that the cameras usually face the same direction you are travelling, so the radar waves are not directed to oncoming traffic. The radar dector is front facing and relies on the dector picking up 'scatter' - being some of the radar waves that are bounced in your direction from the surrounding area or from other vehicles. If its a clear and open road then there are no objects to bounce the radar waves in your direction and wont be picked up.
Also, they are highly prone to false alarms from this like radio interference and sometimes automated doors on shops but I believe the better (or, more expensive) filter many of these out.
I am not sure but I thought they were being made illegal in the UK at some point.
The other, and I believe a far more popular choice is the GPS type of radar dector such as Snooper etc. This works in a very different manner. The police / government / council or whoever register the GPS co-ordinates of all fixed cameras and allow companies such as Snooper access to these locations (no doubt for a hefty £££). All these locations are updated into the Radar Dector which has an in-built GPS receiver and alerts you when you are travelling towards a location and doesnt rely on picking up radar waves. You will have to update you dector via your PC regularly to get the latest locations and most suppliers of dectors will charge you annually for this service.
As these dont pick up radar waves, it will NOT detect temporary or hand-held guns but WILL detect other camers that use sensors in the road or average speed cameras that the other one wont.
Most hand held cameras (I believe) use a laser which only needs to lock on you you for a few moments and then your caught. My snooper has a laser detector built in in over 3 years hasnt picked up a signal once. The only way it would help is from the very limited 'scatter' effect of a lasr being point at another vehicle and somehow the detector picking op some of these stray waves.
So, I guess in an ideal world you would have a laser, radar and GPS device built in.
And then there are also electronic devices that jam a laser signal which is something different.
My personal experiences with radar detectors that pick up radar waves has been very poor, however, my Snooper (S3 I think) that uses a GPS is excellent and has without a doubt slowed me down at the right points and saved me points...
Hope that helps,
Rob
