New detecting method?

[wam]

Hi, I just tried Hot Wheels Radar Gun.
I got it for $2 from Sunday market. It is a “toy” to measure speed of slot cars or other toys. The super thing is that it operates at 10.525GHz, it has digital display showing 3 digits representing speed. For curiosity I checked it on 50c coin. When I have moved speed gun slowly over the coin it displayed number over 30 for a second. It does it every time up to about 80 cm distance in the air.
Then I have placed coin underground about 10 cm and moved speed gun about 5 cm above ground – it was the same result when passing over the coin. It works.
I see some of them on ebay for around $30 (used one must be much less).
Did one make some experiments with this toy – like modified reflecting part or so.
I checked the wire with signal from the head with oscilloscope and it goes up and down while object displaces location in the front but the number is produced only when DC level varies fast enough – so it is possible to sense object even in static condition if CRO or DC volt meter is connected to wire “SIG” from PCB.
I will make more testing – any comments?