I just looked at Valentine's site for the first time and read a little bit about the product.
First of all, from outward appearances, it is simply a pair of receivers, one aimed front, one aimed back, and it determines side-presence by looking at the ratio of power received through the front antenna and the power received through the rear antenna.
In other words, if the radar from the front is much stronger than the radar from the back, it determines the radar is ahead. Vice versa for behind. If the power received is similar, it determines the radar source is off to the side.
Determining how many radars are in the field of view is a simple matter of counting the number of different power ratios being received.
Most target-acquisition radar is pulsed, and the pulse width and rate are chosen to established the minimum and maximum range of the radar (yes, there is a minimum). False alarms like other detectors and door openers are usually continuous wave, so again, it's pretty easy to filter those out because it's simply an unmodulated carrier that any good Finite Impulse Response filter can be programmed to remove.
I doubt there's a processor in this thing that is fast enough to actually identify the signature of the incident radar (pulse width, type, train length, etc). That would cost a fortune and require a lot of power.
Anyway, radar detector technology is not all that sophisticated in general.
One thing he claims on his site that disturbs me (because it is blatantly untrue) is that radar is "completely blocked by solid objects." This is completely false. Any solid object that is NOT a perfect electric conductor, or close to it, is going to allow the radar signal to pass through it to a significant degree. Even perfect electric conducting targets will scatter incident radiation in all directions.
I think it is wise to consider that, even though there might be a hill or a grove of trees between you and the radar, it may still be possible for the radar to pick you up - especially if you are the lone target.
No radar system that has a single transmitter and a single receiver co-located and non-sweeping can discern and positively identify multiple targets. At best, the officer will see more than one speed, but the radar unit will not be able to tell him/her which speed goes with which target. The better radar units will give signal strength for each target, so if there's a tractor trailer and a VW rabbit in the field of view, the officer can manually see that the stronger signal goes with the big truck and the smaller one with the rabbit - *IF* he can prove the truck has a larger radar cross section than the rabbit (this cannot be simply assumed). I doubt any officer comes to court prepared to offer proof that any one vehicle has a larger or smaller RCS than another.
So, never forget, if you are in a crowd of cars and the cop is using radar, it is unlikely to the point of near impossibility that s/he was able to positively identify YOUR vehicle as the target displayed on his radar.
It is unfortunate that most traffic courts are just kangaroo courts is because governments have exploited the ignorances of the populace in order to hand down bad justice in exchange for money. An authority will spend an infinite amount of taxpayer money to convict you on a bogus ticket, so unfortunately you must also be willing to spend an infinite amount of your own money to obtain real justice.
Also, higher courts have repeatedly upheld "blanket, dumb radar" as valid simply because a) the judges don't know any better themselves and b) there is not enough willingness on the part of The People to mount an affirmative defense.
Oh well, end of tirade...
