Ground waves?

This is probably a question for someone like Jimbonzz. I have used the search function and came up empty handed.

I was wondering if microwaves propagate in ground waves also?
The reason I ask is because I have a sti-r+ mounted about 8 inches off the ground behind a bumper and a redline mounted high in my windscreen and my sti-r always alerts before my redline. Every time.

I done a little experiment and turned off X and Ka bands on both detectors to make things even and the remote mount always wins on K band or any band for that matter.

Which brings me back to my ground wave theory. Does it hold any water?:confused:

MEM-TEK had a similar idea of the hood helping to reflect some radiation to the detector, thus increasing alert time.

I'll second your motion that I believe the ground, terrain in general, will help concentrate a signal help out the detector. For instance, have you noticed that if a LEO is shooting radar into or in a valley you get an alert much sooner then if you're on a flat or over a hill?

Just an observation, I have no numbers or measurements to follow up.

Your windshield will attenuate the signal slightly. Some are worse than others, those with metallic tints or conductive defogging systems can cause real problems with RDs.

But, even with a normal windshield, you'll get at least some better sensitivity from a detector mounted externally.

Another possibility is your STi-R+ happens to be a "hotter" unit than your Redline. They use the same platform, so, in a perfect world, they should have the same amount of sensitivity, but manufacturing variances and component tolerances make some units perform better than others.

Are you running both in Highway mode? Are you using Ka-band segmentation on the STi-R+?

I bet in heavier traffic the Redline has better reception since it will have a better "view of the road". Do you find this to be the case?

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Originally Posted by Reflections

MEM-TEK had a similar idea of the hood helping to reflect some radiation to the detector, thus increasing alert time.

I'll second your motion that I believe the ground, terrain in general, will help concentrate a signal help out the detector. For instance, have you noticed that if a LEO is shooting radar into or in a valley you get an alert much sooner then if you're on a flat or over a hill?

Just an observation, I have no numbers or measurements to follow up.

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I can't say I have. But I have had some awesome long range alerts with hills and corners involved.

Have you noticed a difference if vehicles are in front of you, therefore affecting the ground waves. With vehicles in front of you wouldn't you expect better results from a detector mounted as high as possible?

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Originally Posted by randypk

Have you noticed a difference if vehicles are in front of you, therefore affecting the ground waves. With vehicles in front of you wouldn't you expect better results from a detector mounted as high as possible?

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My car is pretty low, so a high mount is more blocked from traffic than my remote which can see under cars.

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Originally Posted by kpatz

Another possibility is your STi-R+ happens to be a "hotter" unit than your Redline. They use the same platform, so, in a perfect world, they should have the same amount of sensitivity, but manufacturing variances and component tolerances make some units perform better than others.

Are you running both in Highway mode? Are you using Ka-band segmentation on the STi-R+?

I bet in heavier traffic the Redline has better reception since it will have a better "view of the road". Do you find this to be the case?

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Both in Highway mode.
Traffic or no traffic STi-R+ always wins. I have even held the redline out the window thinking the windscreen could be affecting it.
I do have RDR off and only two Ka segments on. But for this test I made it fair by only having K band on both detectors.

Maybe the STi-R is just hotter, $1200 hotter actually so I guess it should.

Never thought of it that way. Are there any tests that can show any significant differences between hi/low mounting?

Always looking for optimum placement!

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Originally Posted by barryswanson

This is probably a question for someone like Jimbonzz. I have used the search function and came up empty handed.

I was wondering if microwaves propagate in ground waves also?
The reason I ask is because I have a sti-r+ mounted about 8 inches off the ground behind a bumper and a redline mounted high in my windscreen and my sti-r always alerts before my redline. Every time.

I done a little experiment and turned off X and Ka bands on both detectors to make things even and the remote mount always wins on K band or any band for that matter.

Which brings me back to my ground wave theory. Does it hold any water?:confused:

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The ground acts as a cutoff for radar signals and the reflections off the ground would be much weaker than direct line of sight. As another very knowledgeable member once stated.........reflections off the ground (or hood of your car) could actually detract from the sensitivity of your RD. That is because the reflection would be out of phase with the direct signal as they arrive at your antenna which would incurr phase cancellation.........ie. reduced gain by the antenna.

I believe it's primarily that you have a HOT STi-R! Also, if you had RDR off during your test, that appears to give a decent boost in both reaction time AND sensitivity on the M3. Very similar to Ka Guard off on the V1.;)

The higher the mount, the better the reception, it's a fundamental LAW of Radar Detectors. Anything that seems contrary to that rule has us looking for other reasons for the apparent difference in performance.......ie. bad windshield or variance between detectors.

Of course we'd know for sure if you put that STi-R antenna up on the windshield for a few days and the RedLine behind the bumper!:p

This would be simple refraction of the inital wave itself passing through a time space continum. Radio waves don't always end up propogating in a straight line. They take akward flight paths, and their radiation can reflect, defract, and so forth. The emissions you are getting down low are reflections off of the pavement refracting up into the sesor. Though this would harm over the hill refractions and is not recommended. For Lidar you would be in the right position. However, when it comes to radar you are better to be mounted higher to get a better chance of advanced warning around objects such as rises in the roadway surface etc. Jimbonzz would likely 2nd me on this we have tested devices together before on more than one occasion. He mounts High himself for Radar, Low for lidar for this purpose.

Alpine-

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Originally Posted by barryswanson

This is probably a question for someone like Jimbonzz. I have used the search function and came up empty handed.

I was wondering if microwaves propagate in ground waves also?
The reason I ask is because I have a sti-r+ mounted about 8 inches off the ground behind a bumper and a redline mounted high in my windscreen and my sti-r always alerts before my redline. Every time.

I done a little experiment and turned off X and Ka bands on both detectors to make things even and the remote mount always wins on K band or any band for that matter.

Which brings me back to my ground wave theory. Does it hold any water?:confused:

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When I first read this post I noticed the term "ground wave" used in a slightly wrong manner - ground waves travel along the Earth's surface while sky waves travel up into the ionosphere and are then refracted back to the ground well beyond the range of ground waves.

As to your problem in performance, the two detectors are most likely differing in sensitivity only. There would be (in a few cases) some radar signals ducting along the pavement due to its material,surface moisture, higher temperature than several feet higher, etc. But the most likely reason for the results you have is just that one RD is a lot hotter than the other. Yes, if a car was right in front of you, the low mounted antenna would maybe pick up some signal from under that car whereas the windshield mount would suffer signal loss from the car ahead. But the greater the distance between both cars increases, the less advantage the "under the car ahead" would be. So the bottom line is, as others said, the ST has a hotter receiver than the Redline. I guess you sometimes get what you paid for but that much for a RTD? I thought $400 was steep for a V1 :eek:

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Originally Posted by Mr Q

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Originally Posted by barryswanson

This is probably a question for someone like Jimbonzz. I have used the search function and came up empty handed.

I was wondering if microwaves propagate in ground waves also?
The reason I ask is because I have a sti-r+ mounted about 8 inches off the ground behind a bumper and a redline mounted high in my windscreen and my sti-r always alerts before my redline. Every time.

I done a little experiment and turned off X and Ka bands on both detectors to make things even and the remote mount always wins on K band or any band for that matter.

Which brings me back to my ground wave theory. Does it hold any water?:confused:

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When I first read this post I noticed the term "ground wave" used in a slightly wrong manner - ground waves travel along the Earth's surface while sky waves travel up into the ionosphere and are then refracted back to the ground well beyond the range of ground waves.

As to your problem in performance, the two detectors are most likely differing in sensitivity only. There would be (in a few cases) some radar signals ducting along the pavement due to its material,surface moisture, higher temperature than several feet higher, etc. But the most likely reason for the results you have is just that one RD is a lot hotter than the other. Yes, if a car was right in front of you, the low mounted antenna would maybe pick up some signal from under that car whereas the windshield mount would suffer signal loss from the car ahead. But the greater the distance between both cars increases, the less advantage the "under the car ahead" would be. So the bottom line is, as others said, the ST has a hotter receiver than the Redline. I guess you sometimes get what you paid for but that much for a RTD? I thought $400 was steep for a V1 :eek:

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It's all relative. Last ticket out of state I received was in excess of $600! I didn't have the V1 with me at the time. May not have made a difference, but it certainly wouldn't have hurt, either. :)

Just got wind of a gentleman in Canada that got nailed with a total out of pocket in excess of $1500! Sorta makes the $400 investment hedge look like cheap insurance. :)

VG

How true that is. I rarely speed, at most over 5 mph over the PSL and people ask why I use a detector. I explain that my last speeding ticket was due to a non-calibrated gun and instead of fighting the ticket, I paid it and have been using a RD since. With ticket prices and insurance surcharges, the V1 has paid for itself many times. When it alerts, I drop to 5 mph under the PSL every time to protect from mis-calibrated guns and it has kept me ticket free for many years.