Review: AKK FX2 / X2 Ultimate VTX 1200mW

Looking for long range 5.8GHz video transmitter? Check out the AKK FX2 and X2 Ultimate 1200mW VTX! They are also capable of transmitting at 25mW and 200mW, so you can use it for indoor flying as well as racing with others outdoor.

Specifications

The AKK X2 and FX2 VTX’s have the same spec, apart from the form factor (dimension) and weight.

  • Input Voltage: 7V to 26V
  • Output Voltage (BEC): 5V / 500mA (designed for FPV camera only)
  • Supports Smart Audio (VTX Control)
  • Supports Pitmode
  • Output Power settings: 25mW, 200mW, 600mW, 1200mW
  • Antenna connector: MMCX
  • Built-in Microphone
  • Connection: 6-pin connector
  • X2 dimension: 22x32x8mm; Weight: 6.8g
  • FX2 dimension: 36x36x5mm; Weight: 9.6g

What’s improved from the old version?

The “Ultimate” is an upgrade to the previous FX2 / X2 VTX. The improvements include:

  • Higher maximum output power (1200mW vs. 800mW)
  • Support for 6S LiPo (26V vs. 24V)
  • Beefier 5V BEC (500mA vs. 300mA)
  • Upgraded microphone
  • 15%-20% lighter in weight (roughly)
  • X2 is now equipped with MMCX rather than SMA

However the “ultimate” is $7 more expensive than the “non-ultimate” version. So you might want to consider the cheaper FX2 / X2 if you don’t use 1200mW, or 6S :)

AKK FX2 Ultimate VTX

The AKK FX2 VTX is designed to be mounted in the FC stack (30x30mm mounting holes). It has a MMCX connector, a push button to change VTX channel, band and power, and a single digit display.

All the components are built on the top of the PCB, there is nothing on the underside. This makes a thinner board and easier to install in the stack.

The package comes with a MMCX to SMA pigtail, and a silicone cable for the power and signal.

AKK X2 Ultimate VTX

The AKK X2 is in a smaller form factor, so you can install it anywhere in the frame. If you don’t plan to install the VTX in the FC stack (e.g. in an ultralight build there is no room), then you probably want to get the X2 instead of the FX2. It’s a few grams lighter too.

Same as the FX2, the X2 has a MMCX connector, a push button and a single digit LED display.

The X2 VTX comes with a MMCX to SMA pigtail, and a silicone cable for the power and signal.

Here is the manual describing the operation of the VTX.

Actual Output Power Testing

I tested the actual output power of both FX2 and X2 Ultimate VTX using the ImmersionRC power meter V2 on all 8 Raceband channels (see all 5.8GHz bands and channels).

FX2 Ultimate

R1 5658 R2 5695 R3 5732 R4 5769 R5 5806 R6 5843 R7 5880 R8 5917
25mW 12.9 18.7 25.1 27.6 33.7 38.7 40.0 37.2
200mW 205 224 245 233 266 289 277 240
600mW 550 590 605 561 540 595 555 545
1200mW 870 840 960 800 800 870 860 730

X2 Ultimate

R1 5658 R2 5695 R3 5732 R4 5769 R5 5806 R6 5843 R7 5880 R8 5917
25mW 21.3 25.5 30.5 30.9 33.2 36.9 36.9 33.9
200mW 235 232 253 211 214 227 266 229
600mW 546 574 607 535 600 630 522 505
1200mW 1040 920 900 900 1030 1020 1000 872

Do you really need 1200mW?

Theoretically, higher power help increase maximum range of your VTX, but there are many other factors that can also affect your range. Not to mention higher VTX power can introduce some potential problems.

To maximize range, VTX power is probably the last thing on my list. You should optimize other parts of your FPV setup first. Using suitable FPV antennas for both transmitter and receiver, and getting a diversity/multiversity video receiver are just as important.

One downside with high transmitting power is multi-path interference, especially when you’re flying in environment such as rocky terrain and cliffs. Your VTX also gets much hotter which can affect the performance of the transmitter without adequate cooling. When I was testing the VTX on the bench, I noticed the power drops considerably over time if there is no cooling, and it gets really, really hot, so that’s something you should beware of.

Most importantly, you should follow your local regulation regarding the maximum power you are allowed to transmit. Be responsible and don’t break the law.

Audio Quality

I haven’t tested audio in a quad yet, but I briefly tested it on the bench and it sounded quite noisy. The static noise is really loud to the point I can barely hear myself when talking to the mic.

But hey, at least the mic is working this time! It wasn’t working with the older FX2 and X2 when we tested it last time.

Pitmode

There doesn’t seem to be anyway you can enter or quit Pitmode using the button. The only way to enter or quit Pitmode is by using Smart Audio (VTX Control).

20 thoughts on “Review: AKK FX2 / X2 Ultimate VTX 1200mW

  1. Brandon Allen

    I bought one of these, but it might be an older version as it’s only 800mw. The video signal is incredibly noisy. I’m having to build a filter for the power supply on this thing. I think my combo of omnibus f4 which has an integrated PDB that’s apparently not adequately filtered for the VTX power supply and the AKK FX2 which apparently doesn’t have filtered input power makes this pretty worthless as a VTX. I have had way better luck with $8 dollar boscam 600mw units with the dip switches (despite having different dip-switch patterns between each model I buy somehow).

    The smart audio feature is nice and worked great and easily for me but as soon as I take off the static in the video feed is so terrible I’m about to chuck this thing in the trash.

    Anyone else have issues like this?

    Reply
    1. Denny

      The vtx harness has too many grounds use a tramp vtx harness and re-pin the the rest of the wires correctly. Good luck

      Reply
  2. Julien Dumas-Pilhou

    Would you happen to know the order of the pins for an AKK fx2-ultimate. I would like to direct solder but the labels do not match the pins

    Reply
  3. rcschim

    Hi Oscar, you’re right – over 1 watt is really “bruteforcing” the video transmission :)
    It’s way smarter to have good receivers, antennas…

    on my measurements with the irc pm v2 I used F4 (5800) since I can set the PM to exactly that – but there the power output is quite low. On E3 (5665) they believe it’s the highest possible RF power – and indeed I got around 1.4watts shortly – dropping lower with heat quickly as you say.
    have you tested the Foxeer clearTX also? would be interested in your findings…

    Reply
  4. Claudio Costerni

    I just received today the X2 Ultimate.
    So the real max power is around 1000 mW, 1200 is false.

    Reply
    1. Oscar Post author

      it was capable of putting out 1300mw but it drops to 1000mw seconds after due to the heat it generates so in reality it can’t get that powerful IMO.

      Reply
  5. Pork

    Just ordered another one hooked up to 4s battery pads after it wasn’t transmitting video feed on the 5v supply built in the esc and immediately smoked I thought this was able to take direct 6s only had it on the 3rd power setting maybe I got a bad one ordered another gonna be pissed if for whatever reason the second one dies too have been getting almost exclusively faulty everything for the past 2 months could have built another quad with all the money down the drain

    Reply
  6. Pol

    Can’t get smart audio to work on two fx2s. Read somewhere it’s because BF fixed a bug on the firmware for non licensed smart audio products. Yours working fine?

    Reply
    1. André

      Hi Pol!
      Do you have an older version of the FX2 (not the same as the FX2 ultimate)? The smart audio implementation of the first version is not compatible with BF 3.3. The newer ones are said to work fine.

      Reply
    2. Kimi

      ci.betaflight.tech/job/Betaflight%20Maintenance%203.3%20%28AKK%20-%20RDQ%20VTX%20Patch%29/lastSuccessfulBuild/artifact/obj/
      BF fixed the bug for AKK. Old version (3.2.x) AKK VTX pwner can get their FC updated with latest BF 3.3.2
      New version AKK VTX have no problem with BF 3.2 and 3.3.

      Reply
  7. André

    Some additional questions:
    1. Is the microphone working?
    2. How thick are these VTx? (Was thinking about one of them for my Chameleon TI)
    3. How high is the output power in PIT mode?
    4. Is it possible to power up in PIT mode by pressing a button etc.? I was told PIT mode can only be activated via the OSD, what would make it quite useless in the field.

    Reply
    1. The Gettys

      I have both of these VTXs. The mic works fine. Very clear audio of prop noise in my DVR footage. I am not sure of the thickness but I am using one of each in Armattan Roosters. The FX2 will fit fine as long as you aren’t using a 4 in 1 ESC. The X2 is a tight fit behind the FC.

      Reply
  8. Ludus

    Hi!

    There is a mistake in here: Beefier 5V BEC (500mW vs. 300mW), you’re talking about watts and I think you we’re talking about Volts.

    Greetings.

    Reply

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