Radar jammers in Fedex trucks?

[cdonner]

Hi from Mass.
I have a SportsRadar gun in my basement pointing at the street in front of my house (at an angle). Every time a Fedex truck goes by, it reads between 10-20 miles higher speeds than what I would guestimate from experience. It seems that a jamming device would produce lower readings, no? Any ideas what is causing these higher readings?

cdonner

[v1user]

Hmmm. On one hand your guestaments could be wrong. But on the other, my dad knows a veteran UPS driver in MO/IL who claims to use a radar jammer in the cab of his truck. He said he keeps it in a box in his truck. This guy is also a Belscort dealer...

[Lucky225]

Hi from Mass.
I have a SportsRadar gun in my basement pointing at the street in front of my house (at an angle). Every time a Fedex truck goes by, it reads between 10-20 miles higher speeds than what I would guestimate from experience. It seems that a jamming device would produce lower readings, no? Any ideas what is causing these higher readings?

cdonner

SportsRadar guns are by no means something I would rely on for an accurate reading.. the fact that Fedex trucks are a LARGE object and will reflect radar more easily is one reason it may be showing higher then what you visually estimate, or it could just be your estimation is wrong due to an optical illusion of bigger vehicles appearing to travel at a lower speed. Just my 2 cents.

[mattcam3]

Hi from Mass.
I have a SportsRadar gun in my basement pointing at the street in front of my house (at an angle). Every time a Fedex truck goes by, it reads between 10-20 miles higher speeds than what I would guestimate from experience. It seems that a jamming device would produce lower readings, no? Any ideas what is causing these higher readings?

cdonner

SportsRadar guns are by no means something I would rely on for an accurate reading.. the fact that Fedex trucks are a LARGE object and will reflect radar more easily is one reason it may be showing higher then what you visually estimate, or it could just be your estimation is wrong due to an optical illusion of bigger vehicles appearing to travel at a lower speed. Just my 2 cents.

If an object is larger or smaller, that should only affect the amplitude (strength) of the returned signal, the Doppler shift should remain the same (assuming the gun calculates speed from the Doppler shift).

My guess is on bad visual estimation, although that doesn't account for a 20 MPH difference...