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<div dir="ltr" data-setdir="false"><div>Bob,<br>
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If you want me to keep you safe I'll say YES, but the reality is, most radar units in police cars do not use a cosine rule.<br>
<br>
Part of our training is that we should keep a 10 degree or less angle between our unit and the target. <br>
<br>
But, any increase in angle will only benefit the suspect. If they are
going 30 mph over the speed limit and our radar indicates that you are
only going 20mph over the limit, then you just got away with the 10mpg
delta.<br>
<br>
Just remember this, when you double your speed, you quadruple the impact force if you crash. <br>
<br>
Speed Kills!<br>
<br>
Rusty<br>
WB4BSD</div><div><br></div></div><div><br></div>
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On Monday, June 8, 2020, 4:07:49 PM EDT, Robert Bruninga <bruninga@usna.edu> wrote:
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<div><div dir="ltr">APRS speed related?<br></div><div dir="ltr"><br></div><div dir="ltr">Have cop radars implemented the Cosine rule? IE, it should be possible to<br></div><div dir="ltr">include a magnetic compass in a handheld radar gun and to initialize it in<br></div><div dir="ltr">the direction perpendicular to the road with just a button push...<br></div><div dir="ltr"><br></div><div dir="ltr">Then the gun can display the actual speed using the cosine rule as the cop<br></div><div dir="ltr">sweeps to keep up with your car, (or statically when the cop is at an<br></div><div dir="ltr">angle to the line of approach) and not just the relative speed (which<br></div><div dir="ltr">approaches zero) as the car goes past the perpendicular point.<br></div><div dir="ltr"><br></div><div dir="ltr">Curious as to whether I need to consider this when speeding past a<br></div><div dir="ltr">radar...<br></div><div dir="ltr"><br></div><div dir="ltr">Bob, WB4APR<br></div><div dir="ltr"><br></div><div dir="ltr">_______________________________________________<br></div><div dir="ltr">aprssig mailing list<br></div><div dir="ltr"><a href="mailto:aprssig@lists.tapr.org" rel="nofollow" target="_blank">aprssig@lists.tapr.org</a><br></div><div dir="ltr"><a href="http://lists.tapr.org/mailman/listinfo/aprssig_lists.tapr.org" rel="nofollow" target="_blank">http://lists.tapr.org/mailman/listinfo/aprssig_lists.tapr.org</a><br></div></div>
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