[Review] Fenix TK11 TAC - I didn't know I needed this until I used it!

rookiedaddy

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Was contacted by Fenix a few weeks ago and received a few lights for testing...
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This is a review of the new Fenix TK11 Tac flashlight.

First thing first, the specifications of Fenix TK11 Tac:
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There is a new switch design that Fenix try on this Fenix TK11 Tac, that is "Advanced Pulse-Frequency-Transmission System", and below is the promo slide for it:
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ya, that doesn't help much...
so I ask Fenix and this is the reply I get:
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great... now I have more questions than it answered...
did a patent search and found 2 patents that "might be" related to this APF: "CN 109945086 A" and "CN 111669880 A". For those who are interested, you can do your research into these patents. As the original filing is in Chinese, you may want to get someone to translate for you. Note that I could be very wrong about the patents in relation to the APF as I'm still confuse by most of the patent filing writings.

Fenix TK11 Tac flashlight:
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a uni-direction pocket clip. it does not locked in place, so you can easily rotate the clip to any position you like, or remove it altogether.

Length and size comparisons to a few other flashlights:
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following the tradition of TK-series, this new Fenix TK11 Tac is built like a tank.

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I can easily operate the Tri-function Tactical Switch with one hand (2 fingers).

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and it feels really great in hand.

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The tail boot button is anodized metal, due to button is exposed/protruded, it's one of the easiest tactical tail swtich to operate and it's super silent too. This tactical switch offers 2 stages of operating level, half press for momentary On and full press for constant On. In both Momentary and constant On, you can switch mode by quickly half press the button to cycle the Low-Medium-High (only in Duty mode), this effectively giving us both Forward-clicky and Reversed-clicky functionality in the same light... something that I never thought I needed until I used this Fenix TK11 Tac. I did not know what I missed until I used it.

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When the mechanical rotary is at this position, the light is in Duty mode. You can cycle the Low-Medium-High brightness by half pressing the switch.

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When the mechanical rotary is at this position, the light is in Locked mode. If your Fenix TK11 Tac is Off when you rotate the mechanism to this position, Fenix TK11 Tac is effectively being locked out. You can't turn-On the light. If your Fenix TK11 Tac is already turned-On (Full press to engage constant On) when you rotate the mechanism to this position, then you are effectively locked in the chosen brightness, including strobe, and you can't turn the flashlight Off (unless you loosen the tailcap).
Besides offering a lock-out option with this rotary mechanism, you can also do a more traditional lock-out by loosening the tailcap quarter-turn.

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When the mechanical rotary is at this position, the light is in Tactical mode. You only have momentary High mode (half-press) 1,600 lumens, constant High mode (full-press), and Variable Strobe mode (full-pressed-and-hold-for-1-second). Although Fenix says it's 0.8 second to engage the Variable Strobe mode... well... I ain't no machine so I go with a second here instead of counting the fractions. Also, it's OK if you hold the button for more than a second even after you've successfully engaged the Variable Strobe mode.

Below is a short video showing the Low-Medium-High mode cycle, and the Variable Strobe mode is out of the normal mode cycle as you need to explicitly engage the Variable Strobe mode by Full-Press-and-Hold sequence.


following are a couple of closed-up shots of Fenix TK11 Tac:
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battery is inserted positive-side towards the head.
Note that Fenix TK11 Tac does not include any battery in the package.

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O-ring and threads are generously lube.

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spring at both positive and negative battery contacts to reduce recoil impact and to cushion any external impact (e.g. drop)

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Luminus SST40 Cool White LED

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The Tactical Strike Bezel... I do however wish that Fenix would offer a screw-on stainless-steel bezel.

My measure output of Fenix TK11 Tac:
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The usual disclaimer: I do not claim the above measured lumens as authoritative nor an indication of over/under-stating the number given by manufacturer. It's calibrated against some known light output (e.g. SureFire, Elzetta, etc.) so take it with a grain of salt and just as a relative reading.
while below is Fenix quoted brightness and runtime table:
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in my testing, however, the Turbo runtime is a bit shorter:
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Fenix quoted the runtime using a 3500mAh Fenix 18650, while I tested using fresh new KeepPower and NiteCore 3500mAh 18650.
When checking back with Fenix on the runtime, I was informed that in Fenix's Lab condition, the Turbo ran for ~2-3 minutes before thermal throttling kicks-in. While in my environment, without fan-cooled, Fenix TK11 Tac sustain ~5 minutes at Turbo brightness before stepping down and when the temperature of Fenix TK11 Tac has cool down a little, there is a pick-up in brigntess (also depending on battery status). This explains the shorter total ANSI/PLATO FL-1 runtime that I'm getting from Fenix TK11 Tac.
With a fan-cooled condition, I'm getting a much longer Turbo runtime, ~15 minutes with KeepPower P1835U and ~8 minutes with NiteCore NL1835HP. This also explains the much shorter total runtime for the fan-cooled KeepPower P1835U, at approximately 74 total runtime minutes.

below are beamshots taken inhouse:
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Fenix E28R is using an optics to give a bigger hotspot while Fenix TK11 Tac is using a smooth reflector, thus, Fenix TK11 Tac will appear brighter with our eyes focusing on the bright hotspot when compare side-by-side, although E28R lights up a larger area in front of user.

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captured using a faster shutter speed. although Fenix E28R is quoted as 1500 lumens, but in my home-made lightbox, Fenix E28R is outputing ~1600 lumens too. Tint on Fenix TK11 Tac is also whiter.

In conclusion, the new Fenix TK11 Tac is definitely a flashlight model that I would highly recommend to any Law-enforcement, Military and Outdoor enthusiast. The new tactical switch at Fenix TK11 Tac is really very impressive, Not only it offers a very quiet and simple operation, but the way it makes it so straight forward for user to configure how one would operate Fenix TK11 Tac, has one of the best UX (User Experience) of any Tactical flashlights I've ever come across. Brova Fenix!

Thank you for reading.
 
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parametrek

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Re: [Review] Fenix TK11 TAC - I didn't now I needed this until I used it!

Advanced Pulse-Frequency-Transmission System

Speculating as an engineer but I think I have an idea what they are doing. Usually these lights with advanced controls in the tail will need an additional body tube (many Nitecores and Olight though Olight uses a custom battery as a 2nd body tube) or wire (HDS) to send signals from the switch to the light. Instead either the switch is actively modulating the power to send a message to the head or the head modulates the power to read passive sensors in the tail.

There is a lot of prior art here. The most well known is the 1-Wire protocol. It works by briefly disabling the power for a handful of microseconds. It even has 2 way communication though that wouldn't be needed here. I also doubt they are using 1-Wire. It is just an extremely well documented example.

We've also seen flashlights using this too. The Niteye MSA series of lights did something similar: http://www.candlepowerforums.com/vb/showthread.php?342720

There are 1000s of ways to implement the tech. I'm certain Fenix's is original. But it is very easy to do it poorly. Do you have any way of measuring PWM? It is particularly easy for these systems to have bad PWM.
 
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rookiedaddy

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Re: [Review] Fenix TK11 TAC - I didn't now I needed this until I used it!

Do you have any way of measuring PWM? It is particularly easy for these systems to have bad PWM.
@parametrek, thanks for the info and links, appreciate it. sorry mate, I currently do not have the tool to properly measure if the tailcap sends PWM signal and at what frequency to the head.
 

Swedpat

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Re: [Review] Fenix TK11 TAC - I didn't now I needed this until I used it!

Thanks for review!
I like the mode spacing. But according to the presented graph, medium mode seems to have some kind of "regulated falling" output.
 

Olumin

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Re: [Review] Fenix TK11 TAC - I didn't now I needed this until I used it!

Probably not something I would be using, but I'm always interested in unique and different interfaces, so it's nice to see something different. Ability for a service-light to run on primary cells is very important too. That drop on high does not look good though.
 

wacbzz

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Re: [Review] Fenix TK11 TAC - I didn't now I needed this until I used it!

I really like this light; it has become my edc to work every day. My only disappointment with this as compared to my PD35 TAC is the lack of a low mode when switched to the "tactical" setting.

Nice review. :thumbsup:
 

Olumin

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Re: [Review] Fenix TK11 TAC - I didn't now I needed this until I used it!

I really like this light; it has become my edc to work every day. My only disappointment with this as compared to my PD35 TAC is the lack of a low mode when switched to the "tactical" setting.

Nice review. :thumbsup:

I have always been interested as to how people carry full sized lights. Do you simply clip it into your pocket or do you use a holster? And why do you decide on carrying an 18650 sized light and not something smaller? Do you need the Runtime or Brightness?
 

wacbzz

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Re: [Review] Fenix TK11 TAC - I didn't now I needed this until I used it!

I have always been interested as to how people carry full sized lights. Do you simply clip it into your pocket or do you use a holster? And why do you decide on carrying an 18650 sized light and not something smaller? Do you need the Runtime or Brightness?

Well, speaking strictly for myself, I'm not small and I don't wear tight pants. You cannot really tell the TK11 TAC is in my pocket...

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I like this type of light as my edc because when I want to see something, I want to SEE something. I work a bunch after dark, so my, say, HDS - for me - just won't work. Plus, I'm not a fan of lights that disappear in my hands as an edc. I carried the PD35 TAC for a long time, but I like this mode switching mechanism better.
 

Olumin

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Re: [Review] Fenix TK11 TAC - I didn't now I needed this until I used it!

Well, speaking strictly for myself, I'm not small and I don't wear tight pants. You cannot really tell the TK11 TAC is in my pocket...


I like this type of light as my edc because when I want to see something, I want to SEE something. I work a bunch after dark, so my, say, HDS - for me - just won't work. Plus, I'm not a fan of lights that disappear in my hands as an edc. I carried the PD35 TAC for a long time, but I like this mode switching mechanism better.

Thanks man, I appreciate it.
 

prof student

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Re: [Review] Fenix TK11 TAC - I didn't now I needed this until I used it!

So is it safe to say that the TK11 TAC is N-O-T regulated?

I don't expect it to go full blast at 1600 lumens for long, but at 500 lumens? Yes, that seems not much to ask, right?

According to the graph, on medium it seems to have a continuous drop right after ~10 minutes! :(
 

parametrek

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Re: [Review] Fenix TK11 TAC - I didn't now I needed this until I used it!

@parametrek, thanks for the info and links, appreciate it. sorry mate, I currently do not have the tool to properly measure if the tailcap sends PWM signal and at what frequency to the head.

Sorry for the confusion. That wasn't what I meant. Do you have any way of measuring if the light has PWM? When Niteye did this they had very bad PWM on nearly every mode. Since sending messages involves cutting power it is common for the LED to flicker as a consequence.
 

rookiedaddy

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Re: [Review] Fenix TK11 TAC - I didn't now I needed this until I used it!

Do you have any way of measuring if the light has PWM? When Niteye did this they had very bad PWM on nearly every mode. Since sending messages involves cutting power it is common for the LED to flicker as a consequence.
I can't detect any PWM in any modes with the light, i've tried with 1/4000s with my camera and still not detecting PWM.
 

rookiedaddy

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Re: [Review] Fenix TK11 TAC - I didn't now I needed this until I used it!

Fenix TK11 Tac Medium mode runtime plot:
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and comparing to Olight Warrior Mini, both at claimed 500 lumens level:
s7s1TwX.png
 

parametrek

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Re: [Review] Fenix TK11 TAC - I didn't now I needed this until I used it!

I can't detect any PWM in any modes with the light, i've tried with 1/4000s with my camera and still not detecting PWM.

Thanks. That is great. With all the shenanigans from other manufactures it is easy to forget that Fenix has good engineers.
 
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