Mixing Jammer Heads

[zip]

I'm awaiting the delivery of my 9500ci tomorrow to put in my Cayman.

I have downloaded every Porsche install with pics that I could find online and have gotten a lot of good ideas. I am thinking of mounting the dual ci jammer heads in the rear, buying Blinder M27 heads (or maybe LI) for use in the front along with the rear ci head (center of mass mount). The one concern I have with mixing different heads is that it may actually lessen the effectiveness of one or both systems. I read in one forum (this one?) that mounting the rear ci head up front with the other two ci heads actually degraded the effectiveness of that system since the front and rear heads are not synched/phased to fire together. Not sure what other complications would come from mixing brands - Escort/Blinder or Escort/LI. I know to keep some distance between heads, but not sure how much to stop interference (if any).

Any thoughts?

[TSi+WRX]

So far, there's been no conclusive proof of the "sync" issue.

RadarRoy's earlier statements - that the rear head is not "sync'ed" with the front, which was a statement he was given via Escort's sources - has never been proven quantitatively. The only observation that Roy has made was that on his wife's van, the addition of the rear head to supplement the two fronts increased ("worse") PT distance in his testing (Stalker LZ-1), but it was only a qualitative observation.

Similar qualitative observations - albeit with an exact reversal of what's observed: i.e. that in these cases, the PT distances were lessened (i.e. "better") - have been seen of three other hobbyists in this community, who've tried such a setup on their vehicles. However, it is unknown, in these cases, if these vehicles' additional passive measures (extensive, in each case), further mitigated PT, to the point that the addition of the rear head, facing front, may not even have mattered.

What's known, however, is that there are potential physical-design issues that may cause destructive cross-talk to occur with such a front-rear setup - the following is taken from MEM-TEK's analysis of the situation, via an Escort Radar Forums posting:

Wow, I was away for 2 weeks and I really missed a lot! First off, the rear laser shifter is a "thin" design which emits its IR in broad horizontal and vertical cones. The result is that the rear shifter's IR emissions will and do strike the ground not too far back from the rear of the vehicle. And then of course those emissions striking the ground can and do reflect off of the nearby ground and feed back into the IR sensors.

Now lets think about the front shifters. They are clearly labeled "THIS SIDE UP" for a reason. Why? Because the correct side up orientation allows the internal circuit board to act as a shield which blocks the shifter IR emissions from striking the ground too close in front of the vehicle and then feeding back into the front shifter's IR detectors. This feature permits the IR detection circuitry in the front shifter to run "wide open" with maximum sensitivity.

So what happens if you mount the rear shifter up front? Quite simply, the front shifters which have exceptional IR detection capabilities will now detect the rear shifter's IR emissions off of the pavement fairly close to in front of the vehicle. The result is that the front shifter heads appear to be "out of phase" compared to the now front mounted rear shifter head. In short, its a feedback issue caused by mounting the rear shifter on the front of the car. And the result is that, by mounting the rear shifter up front, you have essentially killed the jamming performance of the front shifters. This could be confirmed by targeting the front mounted rear shifter and observing jamming, yet observing hardly any, if any, jamming performance when targeting either of the front shifters.

And the following is my reply:

^ I agree [of the part highlighted in red, in MEM-TEK's post].

I've seen this kind of "mis-sync'ing" with multiple-jammer systems - in benchtop tests (RacerX's was the first to document the Blinder/AL G8 crosstalk), in artificial situations (Ronin/Ronin's_Ride's ZR3/LPP setup, facing a white-painted interior garage wall, in close proximity), and both my own as well as oahuyahoo's ZR3/LI setup in "testing"/physical-world situations, on-vehicle. There are actually several past-posts of mine on RadarDetector.net, RadarReviews.net, as well as SpeedTrapHunter which detail my concerns about multi-system "crosstalk," and in each case, such miscues/mis-syncs (one jammer cues to the jamming output of another, instead of the LIDAR source) are, I believe, the noted cause.

My only question/concern with your exposition above is with the highlighted portion.

In the real-world (not speaking of "encounter situations," but rather, to encompass all physical-world concerns, both in terms of actual encounters, which most term as "real-world testing," as well as in live testing, quantitative, per GOL and other hobbyist-group methodology (distance-to-PT), is it possible to target, specifically one head versus another, given the typical vehicle's forward-profile spacing/size, as well as placement of the jammer heads (and how sensitive the heads are)?

(2) whether there's also individual setup differences (i.e. "critical distance" between heads, visual obstruction of heads [the latter is well-demonstrated by djrams80' LI+ZR4 setup, which provides true-JTG coverage, versus oahuyahoo's initial LI+ZR3 install, which saw destructive interference/crosstalk], or other setup-related concerns, and

(3) whether if such "mis-sync" concerns actually plays out in the real-world, outright (i.e. can there be instances where only select heads are activated, and how much does this tie into issue #2).

Too many questions remain, for anyone to be saying anything as a certainty - and another question also remains: why, if the ZR4 may be problematic in this way, is the ZR3 not.

To me, right now, it's all a bunch of question marks, and much of it stems not only from a technical dissection of the ZR4, in terms of what should, logically, happen (performance degradation), but also what little physical data we have now (in terms of better overall performance), for this data is at-best inconclusive, as the testing protocol was not optimized to quantitate date.

Truthfully, given the current unknowns, and given your desires, I would honestly advise *against* a dual-system of the sort you're proposing.

Given the way the ZR4 as well as the Blinder heads are constructed - plus how sensitive they are - Id' think that it's very likely, particularly on such a "tight real-estate" vehicle such as the Cayman, that adjacent heads may mis-cue onto each other, and cause more headache than it's worth.

In all honesty, I'd just stick with one system.

[zip]

Thanks so much for the detailed reply! Good info.

I'll refrain from putting the REAR ci ZR4 jammer up front. What I will probably do instead is put the Blinder or LI heads up front, and the 2 main ci ZR4 heads in back, unless you think that might lead to crosstalk/queing issues too. I was too disappointed in the GOL test results of the ZR4 heads to rely on them as the main up front defense, though the radar detector itself looks nearly flawless for the mainly city driving I do.

[TSi+WRX]

^ No thanks needed. This is a subject that runs close to my heart, for, as many here know, I also run a multiple-jammer setup.

I leave my ZR3s on "Receive Only" (taking full advantage of their extreme sensitivity, in hopes of early warning - as well as "directional threat indication" via my Link'ed 9500i), and typically, I only run the LIs.

I think that your "revised proposal" should work well on the front, particularly given the vehicle's small size. That, combined with the jamming performance (known) of the LI and (hoped/previewed) of the Mx7 Blinders, should mean that you won't have to worry there, at all.

Out back, the problem remains of whether or not the ZR4s will do much good. Certainly, I'd expect that it would be better than nothing at all, and combined with your vehicle's rather non-traditional rear profile, that may help. But it's something that I would urge you to get tested/optimized, if at all possible.

With rear jamming, there's a lot of difficulties to be had, and the odds are even further skewed against us. Although I think that something is better than nothing, my own philosophy, when it comes to the rear, has always been "balls-out - all-out," and to not spare overkill.

[zip]

So, with my new proposal, you don't anticipate any interference between the two systems at each end of the car?

Maybe I'll opt for an M47 package front and rear and leave the ZR4's up front for detection only as you suggest. Expensive yes, but so are tickets and insurance!! Not to mention the aggrevation of the ticket and court itself! I rarely run hard, but last year that seemed to be the only time LEO was looking! Being in my red S2000 didn't help my cause. Not sure a Porsche will garner any sympathy either!

Any comment on my proposed radar detector location under the skin, behind the nose/bumper?

[zip]

Oh, and what are the difficulties of rear laser protection you allude to? Why is that so much harder than the front?

[TSi+WRX]

Given the wide physical separation between your proposed front and rear setups, despite the fact that they're going to be of two different units (and even makes), it should not be a problem.

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The rear of a vehicle is typically much harder to protect than the front, and this is due to several factors:

(1) *ALWAYS* the presence of a rear plate
(2) large lighting elements, including "retro-reflector" elements
(3) placement of the lighting elements unfavorable versus places to mount jammer heads
(4) less favorable profile (more upright components)

What you'll have going against you are the first three.

What you'll have going for you is the rather unique Porsche rear profile, combined with the Cayman's size.

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As for the RADAR antenna, honestly, I don't know....there's a lot to consider, there:

Ferrari F430 Scuderia Escort 9500ci - Page 2 - Escort Radar Forum

That's one you may have to test, for yourself, and then decide, based on your observations, whether you need to pursue different mounting/setup.

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As for a (delicious and delightful) Cayman escaping notice?

Maybe if you were surrounded by Escalades.

[zip]

Thanks again! This is all good stuff. You confirmed a lot of what I thought I knew, and filled in a lot of gaps for me. Much appreciated.

My ci just arrived minutes ago via UPS! I plan to take my time with it! I'll get started on the actual mount next weekend. I'll probably try the RD behind the nose and see how it does before deciding on whether to leave it there or not. I've been driving with an ix for several weeks so I think I have an idea of what I SHOULD be seeing.

I really appreciate the thorough responses. Will let you know how it went once I've had a chance to evaluate.

Warm regards,
Zip