Radar detector reactivity tests shows how the current best radar detectors alert to instant-on radar.


Radar detector reactivity tests of the best radar detectors

Speed over sensitivity, wins the day

Updated: 3-25-24  by Veil Guy

Radar Detector Reactivity TestRadar detector reactivity & responsiveness tests


Ever since I discovered the speed detection benefits of Ka-band segmentation in 2008, I’ve put more emphasis on a radar detector’s alert reactivity to instant-on radar, distant brief detections to approaching constant-on radar, and quick-trigger (very quick I/O operation) than on raw sensitivity.

I had read the car magazines’ radar detector tests since the late ’70s and participated in several Speed Measurement Labs closed course testing events, have looked at these sorts of tests, their results, and subsequent conclusions with some level of skepticism.

The reason why, is that I’ve regarded closed-course testing to constant-on transmitting radar as a one-dimensional view of a radar detector’s performance.

In the real-world, there are a number of different factors that come into play that effect radar detection performance, that these sorts of conventional testing often miss.

That’s why we started testing radar detectors in the real-world behind the wheel, making video, and prepared articles long before WordPress blogging software and YouTube existed.

In all of the time of my nearly 46 years of driving with radar detectors–driving with the original Escort against tricky upstate NY troopers who loved to use instant-on K-band at the time–I’ve relied on a radar detector’s responsiveness to catch the trickiest of police radar speed traps, ambushing instant-on radar from a hidden position.

in 2008, my initial discovery of the positive impact Ka-band segmenting had on a Beltronics STi-R’s–detecting brief glimpses of radar even farther away than the Escort Passport 9500ci which was based on the same platform–ultimately has led to every manufacturer to offer Ka-band segmentation to maximize their responsiveness to Ka-band detections.

Although the industry was slow to respond to my findings (they eventually did), today it’s now generally accepted by radar detector enthusiasts–who wish to extract the greatest potential of performance from their radar detectors–to utilize Ka-band segmentation and it all began in 2008.

Remember, every fraction of a second counts when you are soon to be confronted with instant-on or quick-trigger police radar.

Fast forward to today, the focus generally has been on Ka-band by the manufacturers and other review sites alike and most top brands now do well at detecting instant-on Ka-band usage to varying degrees.

However the landscape has changed quite a bit, since 2008.


Advent of K-band collision avoidance systems

The older K-band radar has been used in collision avoidance systems to a great extent since its introduction with Mercedes being a wonderful exception (they use a Distronic system operating at 70Ghz).

I was early at exploring the negative impact these systems were having on radar detectors when I first came across an Audi Q series of crossovers which was the first automotive manufacturer to start using a K-band radar-based technology they called “side-assist.”

I tried in earnest to lobby Audi’s management to change the frequency from the center of K-band, used by police, to another region of K-band (these systems were designed by Hella), but unfortunately I was not successful and since that time, most other in-vehicle systems have followed suit.

Prior to this, the radar detection industry moved along without the need for much innovation as things were pretty static, technology-wise.

If you don’t remember or are too young to know, the Beltronics RX-65, Escort 8500 X50, and the original Valentine One remained essentially unchanged for years!

But that had to change.  With the advent of radar-based collision avoidance (CAS), lane departure, and adaptive cruise control, the radar detector manufacturers were forced to go back to the drawing board to try to filter these obnoxious systems from causing relentless K-band falsing and rendering their otherwise quiet radar detectors nearly unusable around heavily traveled roadways.


A Radar Detector Manufacturer’s First Filtering Attempt

Early approaches were to add a feature, the delayed response to brief K-band detections.

Escort called their filtering approach, TSR (traffic sensor rejection), originally designed to stop the falsing from some stationery K-band traffic flow sensors being deployed in some cities such as Los Angeles and Cincinnati.  These stationery systems “pulsed” K-band radar at a duration ranging from 500ms to 1 second.

By turning on the TSR filtering feature, their radar detectors did indeed get quieter to these sensors but TSR was also found to be effective at quieting the new K-band CAS radars which began appearing around this time.

So in this specific instance, slow was considered better than fast, especially if you were driving on I-5.

Other radar detector manufacturers have followed Escort’s lead with similar filtering approaches which can be turned on or off and as of today the feature is available is most top radar detectors, but turned off by default.

However, the reality is when ever using a slower responding radar detector, you are putting yourself at increased risk for missing an instant-on shot because the duration of the I/O radar transmissions could be shorter than the radar detector’s reaction time to alert to it.

In other words, a radar detector may actually detect the radar, but choose not to alert to it as a means of remaining quiet to a potential “false” radar detection.

Realize, radar detector companies make their money from sales, not returns.

The approach of some radar detector manufacturers, notably Escort, have been to emphasize quietness over performance, for this very reason.

If a radar detector is too “chatty,” it’s more likely that it’s going to be returned and who wants that?

Most typical radar detector users know very little about the technology being deployed and why things work they way they do.

They simply want a quiet detector and one, which in theory, would only alert to genuine radar threats.

That’s all well and good, but as in all things in life, it’s not that simple.


Performance vs Filtering

So what’s the best solution to this dilemma?

The answer is simple, but the execution is hard.

I regard the best radar detector manufacturers as the ones that develop sophisticated signal processing to actually determine what kind of radar is being detected and then either alert or not alert, accordingly.  That is by true signal analysis, not reaction speed.

As I mentioned at the outset of this article, while Ka-band remains the primary focus for some radar detectors and review sites, K-band continues to be a real threat and in some way is getting more so by the day.

The Kustom Signals RP-1 is an especially difficult police radar gun to detect when it uses K-band patch antennas that are low-powered and horizontally polarized (radar detectors are vertically polarized) which makes their radar transmissions extremely difficult to detect at ranges where you are not as risk at getting clocked.

This makes the Kustom RP-1 police radar optimal for close-contact use instant-on ambushes (typically from a hidden position).

Pennsylvania is notorious for this tactic, as their state police use K-band RP-1s almost exclusively.

Redflex is a photo enforcement company that makes an absolutely lethal low-powered horizontally polarized constantly transmitting photo radar and has recently introduced other lethal K-band systems called the Redflex Halo and Halo 2.

Unlike the original Redflex photo radar system, the new Halo and Halo 2’s utilize horizontally polarized, frequency modulated, low powered K-band designed to catch speeders, red light runners, tailgaters, and other traffic-law violators.

Then there’s MultaRadar and Gatso–some of it horizontally polarized, some of it vertically.

The one thing these systems all have in common is that they utilize K-band.

So, just as it was in 2008, so it is today.


The Balancing Act

The best radar detectors and radar detector manufacturers will be the ones that balance radar sensitivity,  alerting speed, and effective filtering.

All three are needed, not just one or two.

We prepared a video, detailing the importance of these abilities:

What makes the best radar detectors, the best? RadarBusters gives you the answers.


Radar Detectors’ Responsiveness to Alerting to Radar

Which brings us to our recent, somewhat informal, radar detector reactivity tests.

Yes, they were orchestrated “controlled” tests, but they were designed to look at a real-world problem–radar detection capabilities to these difficult to detect radar encounters.

Radar Detector Instant-on K-band Reactivity Test

K-band Reactivity Test Pt. 2: Uniden R9 & R8, Redline 360c, Whistler Titan, Valentine One Gen2

Uniden R9, Uniden R8, Escort Redline 360c, Valentine One Gen2, Whistler Titan K-band Reactivity Test

Radar Detector Instant-on Ka-band Reactivity Test

Uniden R9, Escort Redline 360c, Valentine One Gen2 (V1G2) Ka-Band Reactivity & Latch Test

Uniden R9, Escort Redline 360c, Valentine One Gen2 Ka-band Reactivity Test


Effect of Slow Responsiveness to Constant-On Radar

Another thing to consider is that driving with a slow-to-respond radar detector just doesn’t adversely affect alerting to instant-on radar in terms of time, a sluggish radar detector also reduces detection range to constant-on while you are in motion.

If a radar detector takes five long seconds to alert to a radar detection, in the five seconds you may have traveled 600 feet or more, that’s nearly an eight of a mile.

A static closed-course test would show the initial alerting distance, to be sure, but it wouldn’t reveal why it alerted there or if it had seen the radar signal farther away.

It’s quite possible and in fact, quite likely, that a slow detector would have been detecting the radar, but not alerting to it for an extended period of time (and distance).

The end result, though, is that it’s like you were driving with a less sensitive radar detector.

In the instance demonstrated below, we ran an Escort Redline 360c and a Uniden R9 against a very low powered Redflex photo van.

If you look carefully, you will see the Uniden R9 gave an advanced warning, presented us with a nice signal strength ramp-up as compared to the Escort Redline 360c, which only alerted as we passed the source (too late) and at FULL strength.

This suggests to us, that the RL 360c was probably seeing the radar earlier (it has the sensitivity to do so), but failed to alert until it was too late.

We believe this is a real-world example of the adverse effects of driving with a slow responding radar detector.

Mobile Redflex Photo Radar Test: Uniden R9 vs Escort Redline 360c

Uniden R9 & Escort Redline 360c vs Mobile Redflex K-band Photo Radar



Clearly, the Uniden radar detectors performed the very best and were most consistent with the Whistler Titan coming in a close second.

The surprising results of the Escort Redline 360c’s performance, suggests to us they have some more work to do to improve their responsiveness to K-band.

Apparently, there’s a recent narrative online that a recent firmware update has improved the responsiveness of the RL 360c.

If this is true, then surely there is more to be done here.

Valentine’s performance was also surprising.  Earlier V1s were always quick at reacting to I/O.

Even so, the new Valentine One Gen2, appears that it can benefit from some tweaking on K-band.

As good as the Whistler Titan was at these tests and encounters, I am pleased to report that they will be running with these results to make some future firmware tweaks to improve the Titan’s performance even more.

We look forward to their updates and appreciate their interest in continuing to upping-their-game.  As it was, the Whistler Titan already hits above its weight class.

At the end of the day, a radar detector best serves it owner with the ability to alert at the earliest possible moments to real radar threats, especially the most lethal forms of radar, instant-on or extremely low-powered horizontally polarized constant-on photo radar.

This can only be accomplished if a radar detector has struck the right balance of a combination of multiple performance characteristics and not just possesses raw sensitivity.

It’s these sorts of radar detectors that we choose to drive with both as daily drivers and on long multi-state road trips.

As it stands today, our preferences remain the Uniden R9, Uniden R8, Uniden R7. Uniden R4, Uniden R3, and the Whistler Titan for reasons that should be obvious.

Be cautious with any other models as unbeknownst to you as you may be at increased risk of getting a ticket and I would rather have you know this now, than after the fact.

Forewarned is forearmed!

Just like it was in 2008, so shall it be in 2023.

Let’s see how the industry reacts to the results of this test.

Hopefully, the outcome will be similar to what it was 15 years ago.

I just hope it doesn’t take as long as it did, the first time around.

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Drive safe and protected!