Why I Don’t Recommend K40 Radar Detectors or Laser Defusers

K40 products are generally considered among enthusiasts to be overpriced underperformers. There are far better options available.

After purchasing and testing both their RL360di radar detector and the Defuser Optix laser jammer against the competition, I found them both to be bottom of the barrel performers. Once I then had a chance to take a look at the internals, I was surprised at what I saw and suddenly everything started to make sense…

K40 RL360di components

Brand new K40 RL360di radar detector ready to be installed for testing

Here’s a more detailed discussion about K40 and why I do not personally run or recommend their current products.

Poor Radar Detector Performance

First and foremost, the biggest issue for me is its poor performance. For a radar detector that retails in the 4 digits ($1500 for the front only version or $2000 with front and rear antennas, though discounted sale prices vary), in practice it performs closer to the Whistler Pro-3700 (which retails for under $500) than it does any other high end custom installed radar detectors that also cost in the thousands.

K40 RL360di radar detector

K40 RL360di radar detector

In a nutshell, while it can perform adequately in easier situations such as against constant on radar when there’s not a ton of trees or hills blocking the radar signal, when things get tougher, that’s when you’ll see the weaknesses of the K40. Personally I want a radar detector that protects me not just in easier situations, but also in the challenging situations. Vortex's 35.5 Averaged Test Results, Red Barn Course, 5-18-19 What I found with the K40 is that if the officer is using a more challenging to detect radar frequency like 35.5, if there’s hills or curves or trees blocking the signal, if he’s shooting radar in the opposite direction to tag cars from behind as they pass, and/or if he’s using instant on and periodically turning his radar gun off in between cars to avoid being detected from a distance, that’s where you’ll see the K40 fall short and it’s where you’ll find yourself missing the sensitivity offered by the higher tier radar detectors.

You won’t always require the additional sensitivity in every situation to avoid a ticket, but if you want the highest level of protection possible, including protection in even more challenging situations, you’ll want to choose a radar detector that offers better performance than what K40 offers.

Cheap Hardware

It wasn’t until I looked under the hood of K40’s radar detector that the reason for its poor performance started to make sense. Believe it or not, the $1500 K40 RL200di and $2000 RL360di radar detectors are actually the exact same radar detector as the $99 Uniden DFR5.

Check this out…

Uniden DFR5 and K40 radar detector open

Uniden DFR5 (left) and K40 custom installed radar detector (right) without the outer housings

On the left we have the lower end Uniden DFR5. On the right we have the custom installed K40 antenna used in the RL200di and RL360di. Obviously there’s some differences because the DFR5 is a windshield mount so it adds a display, internal speaker, volume knob, laser sensor, etc. while the K40 is essentially just the antenna that hooks up to an external display and speaker.

Now once we look even closer, we’ll see that the radar detector horns (antennas) and RF circuitry, the parts of the RD that do the actual radar detection, are completely identical.

Uniden DFR5 and K40 radar detector with horns open

Uniden DFR5 (left) and K40 custom installed radar detector (right) with horns open

Same size and design for the horn. RF board behind the horn is the same. Here’s a closer look:

Uniden DFR5 and K40 radar detector RF boards

Uniden DFR5 (left) and K40 remote (right) RF boards

Looks insanely similar, doesn’t it? (You can click on the image and zoom in.) It’s the exact same RF layout and circuitry because both detectors are both built by the exact same South Korean radar detector manufacturer who reused the same radar detection platform for different companies.

Once I realized that the top end K40 uses the same hardware as a lower end Uniden detector, things finally started to make sense.

This explains why the performance is on par with lower end detectors. That’s why it can do the job in easier situations, but it struggles in harder situations.

That explains why the BSM filtering is actually decent. It’s the same as the Uniden DFR5. (That said, I last tested it with the RLS2 back in 2015. I’m admittedly not sure how it compares to modern detectors today.)

That also explains why K40 can offer more margin (profit) to dealers and resellers.

The margin on a custom installed K40 radar detector is much higher than a Radenso, Escort, Net Radar, etc., in large part due to the fact that it’s designed using low end components which saves on cost. The competition usually put high end hardware in their custom installed units, the best that you’ll find in equivalent windshield mounts.

  • The Radenso RC M shares the same platform as the Radenso Pro M
  • The Net Radar DSP shares the same platform as the Uniden R3
  • The Escort Max Ci 360 uses a hybrid between the Escort Redline for range and the Escort Max 360c for more modern digital false alert filtering
  • The K40 RL200di and RL360di, however, shares the same platform as the low end budget Uniden DFR5 and it shows in the results

Who Builds K40’s Radar Detector?

So the K40 shares the same hardware as the DFR5? How? Uniden and K40 are completely different companies. Why would they both use the same hardware under the hood?

Well both detectors are actually manufactured by the same South Korean company called Attowave. Attowave produces a bunch of different radar detectors that are sold by various manufacturers. The different detectors all have different features. Some are high end, some are low end. Sometimes some detectors share certain parts or reuse the same radar detection platforms for different companies’ detectors.

Want a list of some of the radar detectors that Attowave builds?

  • K40 RL360di
  • Uniden DFR5
  • Uniden DFR7
  • Radenso XP
  • Net Radar DSP
  • Rocky Mountain Radar Judge
  • Uniden R3
  • Uniden R7

Some of those are fantastic detectors. Others, not so much. The K40 happens to be using one of Attowave’s lower end affordable platforms.

K40 RLS2

K40 RLS2K40 also sells a windshield mount called the RLS2 that shares the same radar detection platform as the RL360di and DFR5.

Instead of retailing for $99 like the DFR5, it retails for a whopping $399. Granted the RLS2 adds GPS functionality that the DFR5 doesn’t offer, but if you want low speed muting and GPS lockouts which are super useful around town, you can step up to the Uniden DFR7 ($159) or Uniden DFR9 ($269). This way you’ll get GPS lockouts, plus you’ll get better performance, but you’ll be paying a fraction of the price. Or heck, just go grab a Uniden R3 ($299) for $100 less which’ll blow it away in literally every metric plus add bonus features like MRCD detection.

I tested the RLS2 back in 2015 and was pretty unimpressed with its performance.

You see why I say the K40 is an overpriced underperformer?

Poor Laser Jammer Performance

K40 also makes a laser jammer as well. Their current top of the line unit is the Defuser Optix.

K40 Defuser Optix laser defusers

K40 Defuser Optix laser jammer

When I tested the Defuser Optix against all the other top tier laser jammers on the market, the K40 came in dead last place. It was the only jammer that was unable to even detect either of the DragonEye laser guns that I shot it with, much less jam the guns. Other jammers jammed those guns to a greater or lesser extent, but the K40 was unfortunately unable to even detect either one.

K40 Defuser Optix Test Results

Against the Kustom ProLaser 3, a popular and relatively easy to jam gun, it managed to go fully Jam to Gun, rendering the gun unable to get a reading at all. That was its best result and is what we’d hope for against every gun.

Against the Stalker XLR and LTI TruSpeed S, two medium difficultly guns, it went JTG against the driver’s side headlight, but had some pretty notable punchthroughs against center mass and the passenger headlight.

The K40 Defuser Optix did great against easy guns, performed worse than the competition against medium difficulty guns, and was useless against difficult guns. So the K40 came in last place in my testing.

YMMV a bit since jammer effectiveness may vary slightly from car to car and installation to installation, but nevertheless, in my experience it performed worse than any other jammer I tested. Out of all the current popular laser jammers, the Defuser Optix offered the least amount of protection.

Lack of Updates

The Defuser Optix has been available since 2016. I purchased the unit brand new about a week before testing and surprisingly, it hasn’t received a single firmware update since it was released. Not one. I even called to check before testing since I wanted to make sure every jammer was fully up to date and K40 confirmed that they hadn’t released any updates for the Defuser Optix since its initial release.

Periodic updates are critical for laser jammers, even moreso than radar detectors, to ensure they can stay up to date as newer laser guns come out on the market that have adapted and been designed specifically to defeat laser jammers. It’s a cat and mouse game and K40 hasn’t released a single update to date which explains why it is ineffective against newer guns.

So the system lags behind the competition and isn’t receiving the necessary software updates to keep it up to date. Not very encouraging…

On a related note, when RALETC opened up the Defuser Optix, they similarly discovered that the laser jammer is also built with much more simplistic hardware than the competition. I guess this is a trend…

K40 Spins My Reviews Out of Context

After spending time testing K40’s products, I published my review of the RL360di radar detector and my review of the Defuser Optix laser jammer. I covered my test results and what I thought about the different features and aspects of the system, both the good and the bad.

In my opinion, based on everything I saw, I feel both systems system are very far behind the competition and not worth purchasing.

After publishing my review, K40 posted a response to my review on their website. In it they focused on primarily the positive aspects of what I thought (totally understandable), but they did it in a way that leaves readers thinking that I had a much higher opinion of their products than I do.

Go ahead and see for yourself. Read my review of the K40 radar detector and K40 laser jammer. Then read what they posted on their website and let me know if you think it gives an accurate portrayal of my thoughts on their products.

They pulled a bunch of my quotes out of context, left out a bunch of critical information, and conveniently forgot to link back to my original review so people could see what I actually said. They have also ignored my request to link back to my original review for full context.

For the record, this doesn’t affect my recommendation one way or another since my reviews are based on testing and using the product, how good the hardware and design is, and how well it actually performs in practice, but this response has left a sour taste in my mouth.

K40 specifically targeted some search engine friendly terms like “Vortex Radar RL360di Radar Detector Review” and “Vortex Defuser Optix Laser Jammer Review” (terms that you may Google for), cherry picked quotes and carefully modified what I had to say to give readers a different impression than what I actually felt, and didn’t link back to my actual review.

They’re hoping that if you search for my review of their products, you’ll read their heavily modified take of my review instead of my actual review and wind up buying the product thinking that it’s one I would recommend.

K40, if you want to use my review in way that benefits you, something that may be challenging but understandably desirable nonetheless, then instead of pulling quotes out of context and leaving out critically important content, intentionally modifying the spirit of my review, and misleading your customers in the process, I ask that you please post what I actually said on each topic in its entirety and link back to my full reviews for appropriate context. If you want to add your thoughts and response afterwards, please feel free, but do not modify or edit what I say in any way. You’ve asked the same from others when they modified an email conversation with you (and even sent out your legal team in response) and so I’m asking you now to simply do the same you’ve asked of others. Thank you.

K40’s Upcoming Higher Performance Radar Detector

K40 is developing an updated higher performance radar detector.

K40 LNA remote FCC label

Most of the information from the FCC filing is embargoed until June 2020, including photos of the RF circuitry, but in the FCC’s test report, the product is referred to as the “LNA Remote.”

K40 LNA Remote

An LNA is a low noise amplifier. In radar detectors, it’s a chip that sits directly behind the horn / antenna and amplifies the incoming radar signal while introducing a minimal amount of additional noise. It helps to make the radar detector more sensitive and gives you longer range.

It’s what Radenso did with their Radenso Pro to boost sensitivity and create the Radenso Pro SE, for example.

K40’s current RL200di and RL360di lack an LNA. If they had one, it would lead to better range. How much better range?

Welllll… I did some testing back in 2015 with the Uniden DFR5 (back when it was called the LRD750) and the Uniden DFR7 (back when it was known as the LRD950). Those two detectors share the same radar detection platform, except the DFR5 / LRD750 lacks an LNA while the DFR7 / LRD950 has an LNA. Unsurprisingly, the LNA in the LRD950 boosted performance and gave me longer detection range. See the complete test results here.

Will K40 take their existing radar detector and simply add an LNA to it? I’d imagine so, but I have no idea if they’ll go that route. Maybe, maybe not. It would be the easiest solution since it uses already existing tech, but I don’t know if this is K40’s plan. It’s simply my educated guess.

I like the $159 Uniden DFR7 for people who want an affordable windshield mount radar detector, but it is not a high end detector. It’s more of a midrange detector.

If K40 stays with this same platform in their upcoming “LNA remote,” that will certainly boost its range, but I wouldn’t expect it to fully be able to keep up with the big dogs across the board.

Attowave also makes the Net Radar DSP (same platform as the R3), but Net Radar has exclusivity on using that platform for remotes and Uniden has exclusivity on using that platform for windshield mounts so don’t expect Attowave to effectively stick an R3 under the hood. Thus K40 will have to use something else and my best guess is they’ll simply add an LNA to their existing detector and call it a newer higher performance version.

Either way, when it comes out, I think it’d be worth testing alongside all the other competitive detectors on a level playing field again to get an idea of how it truly compares. If it performs better (and especially if it adds some additional features that give it a true competitive edge over the competition), I would happily say so and will give it a better review than their current detector, hopefully one that K40 won’t need to spin to make it seem better than it actually is.

Should You Get a K40 System?

K40 logoSo should you get a K40? It’s pretty obvious from this article, but in my opinion, no. Due to its low end hardware, subpar radar and laser performance, and lack of updates, I don’t think it’s worth investing in a K40 at this time.

I don’t run a K40 myself and I don’t recommend it to others. I have nothing against K40 personally. It’s just that the hardware and its performance isn’t competitive, plain and simple.

If you’re looking to get one due to its price point, I would suggest you consider the Net Radar DSP as a better low price alternative.

If you like K40’s minimal look in the cabin, I would suggest you consider the NR DSP with its single alert LED that also can give you directional information, you look at the Escort Max Ci and use its single alert LED and hide the LCD display, or you consider the Radenso RC M and tuck away its controller / display like you’ll need to tuck away the K40 controller.

You can my comparison reviews of the best custom installed radar detectors here.

That said, if you’ve done your research and feel that the K40 is the best choice for you, go pick one up.

If you own a K40 and you’re happy with it, I say great! I’m glad you’re enjoying your countermeasures.

Ultimately I want you to make your own decision. It’s your choice, your money, your vehicle, and your license. It’s your decision which radar detector you choose and it doesn’t really matter to me what you choose. I just want your decision regarding what to choose to be an educated and informed one.

I’m happy testing and sharing my results, good and bad, and I believe you deserve to know how these tools we depend on actually perform and make a decision accordingly.

When it comes to K40, I don’t recommend their products at this time and these are the main reasons why.

This website contains affiliate links and I sometimes make commissions on purchases. All opinions are my own. I don’t do paid or sponsored reviews.

Click here to read my affiliate disclosure.

Why Vortex Radar Doesn't Recommend K40 Radar Detectors or Laser Defusers
Article Name
Why Vortex Radar Doesn't Recommend K40 Radar Detectors or Laser Defusers
The K40 RL200di, RL360di, RLS2, & Defuser Optix offer poor radar and laser performance thanks to their low end hardware. I do not recommend K40 products.

Permanent link to this article: https://www.vortexradar.com/2020/01/why-i-dont-recommend-k40-radar-detectors-or-laser-defusers/


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  1. This is excellent and much needed clarification! I appreciate you taking the time to approach this scientifically, and ensure that what you previously said isn’t taken out of context.

  2. Excellent review. I like how you cracked it open and verified the lower end equipment in the guts.

    • GernBlanston on January 3, 2020 at 11:52 am
    • Reply

    Nice truth bomb. Gets the point across quite well.

    • Christopher Paone on January 4, 2020 at 6:28 am
    • Reply

    Been following you and your super informative articles for years. Thank you for your work and your efforts to educate the public so they can make an informed buying decision. In this case, I would say you are even serving as a watchdog. I think you are being too gracious with K40s actions. It’s as if a bunch of us should contact them and put some heat on them to modify their web site and the way they have quoted you. Clearly they are scamming the public with their way over priced, under performing products. Glad they have finally been called out. They should be ashamed. Makes you wonder how many other companies operate this way. Once again, great work. I think if enough of us were to call K40 and complain on your behalf, things would change pretty quick. Their number is 800-323-5608

    • Christopher Paone on January 4, 2020 at 11:37 am
    • Reply

    Another follow up thought for you Vortex. I did it quick Google search for “K40 Radar Dectector Vortex” and exactly what you said, K40 used SEO so their perspective of what you said showed up first and second in the Google rankings. However your article and comments were like the next 3 listed and showed the first line or two of your comments in each link. Why dont you change the first line of each article to read, ” I do not recommend K40 radar dectors” or something similar so that readers will see that without even having to click on your link and hopefully inspiring them to click your articke to read further. That would be an easy counter to what K40 is doing and will really help anyone doing due diligence on the K40. Interestingly enough, the next few links in my search below yours were people on other sites talking about how K40 changed the meaning of your review. Within time, the word will be out on their tactics.

    • Tzah on January 5, 2020 at 3:01 am
    • Reply

    After reading your review I can only say Thank You.
    Thank you for working so hard on what you do best which is helping us see things through your eyes.
    It seems that the k40 product is all about good profit for the seller. It’s old hardware in new dress.
    That’s not so much of a nice thing to do.
    It’s way better to simply buy an R7 knowing what you’ll get for your money.
    Thanx Vortex

    • Kevin on January 25, 2020 at 11:49 am
    • Reply

    K40- taking people to the cleaners, one RD at a time!

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