R7 with Radar Absorbing Rubber Testing

hiddencam

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So I opened up my R7 today and stuck 3 layers of Mast Technology's Radar Absorbing Rubber over the rear horn to reduce rear horn sensitivity.

IMG_7838.JPG
IMG_7834.JPG
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Thanks to @SixPackABS for sending me a sample of this stuff to test with. This will be a work in progress and I'll occasionally update this thread and share the test results.

Here's the product: http://www.masttechnologies.com/products/mr1-adhesives/mr11-0041-20-with-psa-backing/

Screenshot 2019-07-15 at 11.06.43 PM.png

Here's what a single layer apparently reduces radar various frequencies of radar by. It's a tuned absorber and reflector (they tune the stuff to many different frequencies). This model of it reduces more of K band compared to other police bands like X and Ka bands. Looking at that, a single layer is supposed to reduce K band by about 23 dB. The R3 K band lab sensitivity is reported to be -122 dB, and the R7 is slightly more sensitive than the R3 due to the lens design, so let's assume the R7's K sensitivity is -125 dB. So a single layer would reduce that to -102 dB, which is slightly less than say a V1's rear horn K sensitivity, which is reported to be -108 dB:

Screenshot 2019-07-15 at 11.01.18 PM.png


R3 sensitivity numbers from the lab (the R7 is a smidge more sensitive due to the lens design), unfortunately no numbers for the R7 from the lab.

R3 sensitivity.jpeg


Since I'm testing with 3 layers, that should reduce my R7's K band by a full 69 dB, so 125-69=56, which means sensitivity will drop down to 45%, close to the maximum % drop in Advanced Mode edit: ridiculously low sensitivity - (thanks @alloy00 for the math correction) .

X band will drop by 12 dB, 33.8 by 27 dB, 34.7 by 24 dB, and 35.5 by 15 dB.

Obviously I'm very interested to see how this impacts arrow behavior, and range.

I drove with the modified R7 from Little Rock to Baton Rouge today, and ran Hwy Mode, K filter on, TSF on (most of the way), K wide, K block off. Lots of rural areas, passing through small towns, moderate traffic on the interstate and major highways, lighter traffic on more remote rural highways. And it was really quiet and well behaved with those settings. For the last hour of the trip I turned TSF off and it made it a bit noiser, but not a whole lot. Rear BSMs were virtually non existent, maybe two over 6.5 hrs driving. Several front BSMs of course. Need more seat time in heavier traffic to really comment with full conviction about rear BSMs compared to front, but it's looking like the mod has really improved the user experience. But rear K range does take a hit, and I want to try to measure that in the days ahead, and share video of it.

For now, I've got a quick video showing Ka 34.7 arrow performance while passing a LEO with 1 antenna running (his front 34.7). When I passed the first time, it was a true forward-facing encounter, his front antenna facing ahead. And the transition to the rear arrow was great. Coming back the other way, which created a reverse forward-facing set up, the arrow transition was slower, and took about 300 feet or so, since the signal was weaker once I passed the LEO, and the R7 front horn being unattenuated held the signal strength a smidge longer until the rear strength took over and it flipped. But it was not unacceptable by any means...just not as reactive as the first approach in the video.

-- Double Post Merged: --
Note also, on the 2nd pass, I had my cell phone held up to record, and that blocked the signal to the rear horn.
 

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SixPackABS

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@hiddencam
now thats one clean sexy install. Thats the best and right way attenuating the rear antennae. What is your K band setting?
 

hiddencam

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Amazing what you guys think of to put those pesky K falses to rest.
haha That famous old saying, "Necessity is the mother of invention". @SixPackABS made a thread complaining how his new Mazda CX-5 was constantly falsing the rear horn of his R7, which got me thinking about eccosorb type products, and a bit of googling found the MAST Technologies product, so I suggested he try it and he did. He ordered a sheet of the stuff and has been testing with it since...and his problem was quickly solved with 4 external layers of the stuff. He generously sent me a sample of the stuff (it's $65 per 12"x12" sheet) and here we are, trying an internal application of the material right at the opening of the horn instead of just over the exterior shell. Considering how easy it was to open the detector and apply the stuff, this is a really quick and effective fix for people driving BSM emitting vehicles trying to use an R7.

Back in April during beta testing @Vortex had actually asked Kent at Uniden (Kuni's replacement) if they could add a feature to selectively adjust sensitivity of each horn but it hasn't been implemented yet, and not sure if it's even on their list of things to do. We had also asked about rear horn K-band muting like the V1 has, but same story there. So yeah, necessity the mother of invention and here we are trying to stop those pesky BSMs :D
-- Double Post Merged: --
@hiddencam
now thats one clean sexy install. Thats the best and right way attenuating the rear antennae. What is your K band setting?
Yeah for sure, this is the way to do it. It's really easy to do too, just the 4 bottom screws of the detector, lift that bottom piece of the casing off (nothing is connected to it), then take the rear plastic piece of the casing off (lift it upwards a bit and it comes right off) and you don't even really need to take the horn lens off to place the material over the horn; just cut the correct size of MAST, add as many layers as you need - they'll fit right in the gap.

I actually think you needed 4 external casing layers of it because the horn opening isn't directly blocked, so some reflections are still getting into your rear horn. I think 3 or even 2 layers might do the trick for your CX-5. Test it out and let us know how it goes.

I'm probably going to test 1 layer next. 3 seems too much for my application; I drive an Impala with no nanny systems, so I don't need this many. I just want to be able to run in Hwy mode on the Hwy without any rear BSMs occurring. 1 layer might achieve that...if not I'll test 2 layers.
-- Double Post Merged: --
Oh, and my K band settings yesterday for the road trip were K wide, K block off, Hwy mode, TSF on (then TSF off), K filter on of course. I'll get around to testing various % K settings in Advanced mode as time permits. I'm working crazy hours the next 2 weeks, so won't get much done except when I'm driving from place to place. I've got a 5-hour trip to Texas next week and will definitely test 1 layer for that and might use Advanced mode 50-80% K, and see how that works. Then a 9-hour trip up to Nashville.
 
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BlueV1

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At the moment this appears to be one of the better methods to handle K noise to the rear.

This is reminiscent of passive vs. active crossovers in audio. Simple passive crossovers look a lot like the chart above. (Personally I sometimes prefer a decent passive 2nd or 3rd order crossover. 12dB or 18 dB.)

An active crossover is more like using circuitry to reduce alerting of only K-band to the rear.

If Uniden can do that, it would probably be closer to ideal. I again wonder if a patent is in their way.
 

hiddencam

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At the moment this appears to be one of the better methods to handle K noise to the rear.

This is reminiscent of passive vs. active crossovers in audio. Simple passive crossovers look a lot like the chart above. (Personally I sometimes prefer a decent passive 2nd or 3rd order crossover. 12dB or 18 dB.)

An active crossover is more like using circuitry to reduce alerting of only K-band to the rear.

If Uniden can do that, it would probably be closer to ideal. I again wonder if a patent is in their way.
Interesting about the audio theory! Never heard of that before. Yeah I figured some simple FW coding could be quickly done by the engineers to offer % reduction of K (and X for that matter) JUST for the rear horn. Maybe there are other things in play as you say...
 

alloy00

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Hiddencam - as always, thanks for all you do. I think there is some math error in your calculations above, but I also know I'm "not the expert" and "I didn't stay at a Holiday Inn (Express or otherwise) last night." I don't believe the dB reduction is linear with reception sensitivity. See Uniden R1/R3 Advanced Mode Sensitivity Calculations for example. One perfectly installed layer might be reducing the sensitivity to ~10% of its original.

Now as you said, there is still leakage and the application though clean, is imperfect. Hopefully some techno-savvy folks can chime in here, but I think you might REALLY be turning down the sensitivity of the rear antenna.

ALL that said, whether I'm right or wrong about the theory lol, the testing & practice of one vs. two vs. three layers will be determinative - I'm guessing one or two layers will do it for most folks - awesome on you & @SixPackABS !!!
 

fitz4321

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Wow. Pretty cool thinking. I know you said it is made frequency specific; I would be curious about a test to see if it would negatively affect the KA range.

I like my settings as they are now, but I’m always curious about cool hacks and the positives and negatives that come with them.
 

hiddencam

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Hiddencam - as always, thanks for all you do. I think there is some math error in your calculations above, but I also know I'm "not the expert" and "I didn't stay at a Holiday Inn (Express or otherwise) last night." I don't believe the dB reduction is linear with reception sensitivity. See Uniden R1/R3 Advanced Mode Sensitivity Calculations for example. One perfectly installed layer might be reducing the sensitivity to ~10% of its original.

Now as you said, there is still leakage and the application though clean, is imperfect. Hopefully some techno-savvy folks can chime in here, but I think you might REALLY be turning down the sensitivity of the rear antenna.

ALL that said, whether I'm right or wrong about the theory lol, the testing & practice of one vs. two vs. three layers will be determinative - I'm guessing one or two layers will do it for most folks - awesome on you & @SixPackABS !!!
My math is very likely incorrect because I'm terrible at math :laugh: Thanks, yikes, 1 layer 10% of its original sensitivity, that's a heck of a lot of a reduction!! 3 layers is definitely overkill then LOL I probably should have started with 1 and worked my way up. In fact, I might just open it up today when I have time and take 2 of them off.
-- Double Post Merged: --
And by imperfect do you mean the top layer is not as wide as the two lower ones? I actually measured the width and even the skinniest layer covers the width of the opening of the horn, and the two wider ones are actually wider than the opening. I should have made them all the same width but was rushing to get on the road.

Here's just the skinny piece over the hole, covers the entire opening:
IMG_7823.JPG
 
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DC Fluid

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Testing procedure.
1) Test unit as is for a baseline score.
2) Change 1 thing and 1 thing only at at time, retest to same standards as step 1.
3) When modifications have gone one step too far, revert back to the previous best modification.
4) Long term test best modification, adjust later to desired effect.
5) Enjoy device.
 

hiddencam

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Wow. Pretty cool thinking. I know you said it is made frequency specific; I would be curious about a test to see if it would negatively affect the KA range.

I like my settings as they are now, but I’m always curious about cool hacks and the positives and negatives that come with them.
3 layers did impact range of 34.7 yesterday. I won't hazard a guess at how much yet, but yesterday it was about quarter to half a mile range to forward-facing reflected radar on a straight flat approach to the source (turning the detector backwards as I approached compared to an earlier run with the front horn). For head-on approach to a stronger source, the range impact was much less. But I need a whole lot more testing time (and not just real-world driving around) to drill down the impact. I think 3 is too much, just on my initial impression, so I'll skip any further testing with 3, and go straight to a single layer, then two after that.
-- Double Post Merged: --
Testing procedure.
1) Test unit as is for a baseline score.
2) Change 1 thing and 1 thing only at at time, retest to same standards as step 1.
3) When modifications have gone one step too far, revert back to the previous best modification.
4) Long term test best modification, adjust later to desired effect.
5) Enjoy device.
Yep, agree that's the best procedure. Unfortunately I work and my time is limited. I'm just trying to fit this real-world driving impression and share it with ya'll to get some discussion going, maybe inspire others to join the effort. Testing is a time-consuming thing for sure! And there's never enough time haha
 
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alloy00

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If I am reading the curve above correctly - and understanding the logarithmic scale correctly - and I did not attempt the math as shown in the other thread I referenced - I believe one layer would reduce K sensitivity to 10% of Highway; and Ka to ~40% of range. I THINK lol. Curious to see what testing shows.

As to the install - I take back "imperfect" - it looks like one layer is not as big as the other two. But. As you said, they're all providing coverage. But. As you said, there's probably some leakage. Curious to see what testing shows :D
 

hiddencam

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If I am reading the curve above correctly - and understanding the logarithmic scale correctly - and I did not attempt the math as shown in the other thread I referenced - I believe one layer would reduce K sensitivity to 10% of Highway; and Ka to ~40% of range. I THINK lol. Curious to see what testing shows.

As to the install - I take back "imperfect" - it looks like one layer is not as big as the other two. But. As you said, they're all providing coverage. But. As you said, there's probably some leakage. Curious to see what testing shows :D
Cheers. Yeah more accountable testing is needed. It's all on the fly anecdotal at the moment :spazface: haha

I'm working 12-hour shifts for the next 5 days, which doesn't help either. If anyone in Baton Rouge wants to meet up with me and mod their R7 (I've got plenty of MAST left) let me know. The more testers the better!
 

barry

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Just a quick thought about something that may make a difference in the calculations. The NRL Arch testing approach that was used for MAST's data measures the signal loss of a microwave beam sent from a transmit antenna that goes through the absorber, is reflected by a metal plate underneath, and then travels back through the absorber before reaching the receive antenna. Unless I'm misunderstanding things, the microwaves actually travel through the absorber twice. So, the data shown would represent the amount of absorption for two layers when used in the current application of attenuating the microwaves reaching the detector horn.

I assume MAST's data (i.e., reflectivity) is measured this way because they are more interested in trying to prevent radar detection of a metallic object.
 

hiddencam

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Just a quick thought about something that may make a difference in the calculations. The NRL Arch testing approach that was used for MAST's data measures the signal loss of a microwave beam sent from a transmit antenna that goes through the absorber, is reflected by a metal plate underneath, and then travels back through the absorber before reaching the receive antenna. Unless I'm misunderstanding things, the microwaves actually travel through the absorber twice. So, the data shown would represent the amount of absorption for two layers when used in the current application of attenuating the microwaves reaching the detector horn.

I assume MAST's data (i.e., reflectivity) is measured this way because they are more interested in trying to prevent radar detection of a metallic object.
Cool, thanks!
 

DC Fluid

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3 layers did impact range of 34.7 yesterday. I won't hazard a guess at how much yet, but yesterday it was about quarter to half a mile range to forward-facing reflected radar on a straight flat approach to the source (turning the detector backwards as I approached compared to an earlier run with the front horn). For head-on approach to a stronger source, the range impact was much less. But I need a whole lot more testing time (and not just real-world driving around) to drill down the impact. I think 3 is too much, just on my initial impression, so I'll skip any further testing with 3, and go straight to a single layer, then two after that.
-- Double Post Merged: --

Yep, agree that's the best procedure. Unfortunately I work and my time is limited. I'm just trying to fit this real-world driving impression and share it with ya'll to get some discussion going, maybe inspire others to join the effort. Testing is a time-consuming thing for sure! And there's never enough time haha
Or enough cooperative LEOs....
 

aim4squirrels

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How rigid is this stuff?

Is it possible to stack this stuff in the detector in front of the horn? So you could remove one "slide" at a time for testing purposes?

Maybe you could affix it to a flat piece of plastic (like a cutout from a blister pack) and you could make sides of various thicknesses to swap out for easier testing...
 

NPark

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Pretty cool testing HC! Thanks.

Pretty cool to see it still doing well with those layers on top of it.

I’d wager if you were in a place, like me, that doesn’t have K band, or even in NYS, where its present but light, you could safely drive with k band on, and not have to deal with over the top falsing....




Sent from my iPhone using Tapatalk
 

hiddencam

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How rigid is this stuff?

Is it possible to stack this stuff in the detector in front of the horn? So you could remove one "slide" at a time for testing purposes?

Maybe you could affix it to a flat piece of plastic (like a cutout from a blister pack) and you could make sides of various thicknesses to swap out for easier testing...
It's like a thin rubber sheet, so it's flexible and one side has adhesive so it's really easy to stick over the horn opening. Putting it in and out is also easy (that's what she said) and I'll be able to do it in the car (she said that too). :laugh:
 

Heywood

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Without using the adhesive, how about shrink wrap or Glad Press and seal to hold the material in place on the outside for testing purposes.

Then again if you have enough material, I guess you could stick one then place another over top. Lol.
 

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