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CCFROMFL · 05-19-2013, 09:52 AM

Try to find a speedometer shop that could check the accuracy, provide you with a certified letter if all is correct and provide copy to the court if and when you appear.

If speedometer is actually off, the shop could calibrate for you.

jpharley · 05-19-2013, 10:10 AM

In Indiana, the officer just has to perceive that you are speeding to issue a ticket. We were stopped by several local law enforcement officers at the behest of a game warden towing a trailer about 15 miles after the so called infraction. We were scared because there were so many officers present. We were less than a mile from a stop sign and the game warden was on a side road. He sited us using his GPS after he turned onto the road behind us; game warden issued the citation. Because he did not fill the ticket our correctly, the local DA tore it up. The game warden added information to the ticket after he had given us our copy. By the way, we know were were not speeding.

Brockx · 05-19-2013, 10:16 AM

Quote:

Originally Posted by jpharley

In Indiana, the officer just has to perceive that you are speeding to issue a ticket. We were stopped by several local law enforcement officers at the behest of a game warden towing a trailer about 15 miles after the so called infraction. We were scared because there were so many officers present. We were less than a mile from a stop sign and the game warden was on a side road. He sited us using his GPS after he turned onto the road behind us; game warden issued the citation. Because he did not fill the ticket our correctly, the local DA tore it up. The game warden added information to the ticket after he had given us our copy. By the way, we know were were not speeding.

Man!! You must have honked him off to bother with all that. At one time, maybe yet, Indiana Conservation officer had most power as law enforcement officer.

jpharley · 05-20-2013, 06:09 AM

Nope, just a nice drive. We passed through several towns before he found one he could contact law enforcement to stop us. The DA agreed that the stop was not done properly and actually tore up the ticket in our presence. The game warden could not stop us since he was towing a 4 wheeler on a trailer. There was no way he could have gotten a correct speed because he had to pull out of the side road and catch up to us. By that time, we were at the stop sign.

WDK450 · 07-30-2013, 02:16 PM

I had the same sort of erratic readings this weekend from several roadside speed signs while towing my Bighorn. I too use GPS as my primary speed indicator.
Could it be my wireless TPMS, or just something to do with the vehicle's profile.

SmokyRV · 07-30-2013, 02:23 PM

Quote:

Originally Posted by jsteinberg48

Did you change wheel diameter and tire size?

This is the obvious since. Has anyone read steinberg48's post quoted above?

WDK450 · 07-30-2013, 03:52 PM

Quote:

Originally Posted by SmokyRV

This is the obvious since. Has anyone read steinberg48's post quoted above?

I don't think I understand what you are getting at. Both the OP and myself checked our speed by looking at our GPS's - I don't know of anything more accurate (including police radar) than that. Tire sizes would have nothing to do with the accuracy of GPS readings.

wa8yxm · 07-30-2013, 04:00 PM

When you get to court ask the officer "How fast do YOU say I was going" if he says "The radar" ask for immediate dismissal as the radar is not present. Ask the FCC to revoke the department's radar license as well. (Just to be nasty, don't expect them to do it, but hey)

There are a thousand things that can cause radar to false. I have seen many of them.. This is why some departments write a ticket something like this.

Officer observed speeding car doing about 90 in a 55, Radar CONFIRMED a speed of 89.5 MPH.

wa8yxm · 07-30-2013, 04:03 PM

There is a book you need to get.. Title is something like "Fight all tickets" or Fight every ticket" or "The Ticket Book" not sure of the title as it's been a lot of years since I heard about it.. The author advises folks given Radar tickets by the Michigan state police to admit responsibility and pay the fine but for most departments he says FIGHT IT. The book will explain what I said above and a whole lot better than I can.

Swamp Man · 07-31-2013, 04:16 PM

One question that everyone has failed to ask, and I will ask, as I was certified by the State of Louisiana to operate speed control radar is were there any other large vehicles near you? Radar works on the largest target first (larger reflective surface), and then speed. So, if you were being passed by a larger truck it is possible that the radar picked up the larger vehicle instead of you. Laser radar is incorrect. Radar is microwave energy that reflects off a surface and returned to the sending unit. Laser is a beam of light that reflects off a surface and returns to the sending unit. Laser is a lot more accurate in that you "aim" it at a single vehicle while with radar you have to have the training and experience in choosing the vehicle the radar is indicating.

Sometimes this is easy as in two vehicle going west on I-10 and one is overtaking the other. But at other times, you have to be careful or decide that you are not sure and let it go.

WDK450 · 08-01-2013, 09:26 AM

Quote:

Originally Posted by Swamp Man

One question that everyone has failed to ask, and I will ask, as I was certified by the State of Louisiana to operate speed control radar is were there any other large vehicles near you? Radar works on the largest target first (larger reflective surface), and then speed. So, if you were being passed by a larger truck it is possible that the radar picked up the larger vehicle instead of you. Laser radar is incorrect. Radar is microwave energy that reflects off a surface and returned to the sending unit. Laser is a beam of light that reflects off a surface and returns to the sending unit. Laser is a lot more accurate in that you "aim" it at a single vehicle while with radar you have to have the training and experience in choosing the vehicle the radar is indicating.

Sometimes this is easy as in two vehicle going west on I-10 and one is overtaking the other. But at other times, you have to be careful or decide that you are not sure and let it go.

Swamp Man:
I think what the OP and I are saying is that we think there is something peculiar to the oncoming reflector outline shown by a pickup truck and a 5th wheel front cap twice as high as the truck, that is confusing doppler radar stuff in LEO and roadside speed signs.
When coming up on the roadside speed signs I would get near correct readings from the signs at first, then almost double my correct speed as I got closer.

slackjaw · 08-01-2013, 07:48 PM

It seems to me that the radar is bouncing back and forth between the cap and trucks nose. It seems to be measuring a pulse off the cap then shooting the trucks nose some 15 feet closer on a following pulse. This would erroneously cause the radar to perceive the object to be moving faster than it actually is. Take it from the radars perspective from a distance the cap appears larger than the trucks nose but ( if you get down to the radars level) as you move closer to the truck the nose takes over as the dominant object.

It may be that transition period that is causing the issues, however, laser should not suffered this effect.

Radar is not my primary focus, however, radio wave propagation and all things pertaining is my line of work.

I think the OP has a case and I have a little math to do to back up my theory.

VanDiemen23 · 08-01-2013, 09:54 PM

Do you have a cooling fan IN FRONT of the radiator on that rig? If so I'd suggest blade modulation is a possible culprit.

The cap/cab double bounce is interesting, but not much RCS in a fiberglass cap to produce a return. Besides, both are moving at the same rate, doppler is the same. What you would likely get out of that is constructive or destructive interference of the signal level, but not the doppler in that signal.