Not long ago we had the chance to take a look at the AKK Infinite DVR VTX. This article deals with the new FX3 Ultimate as well as with the FX2 Ultimate Mini FVP transmitter from AKK Technology.
In this article we are going to take a closer look at two high end FPV video transmitters from AKK Technology*. The first VTX is the new FX3 Ultimate transmitter*, which is primarily made for the use on board of a micro quad. The second product is named FX2 Ultimate Mini and represents the shrunk version of the already known AKK FX2 Ultimate VTX (see our review on the original version of the FX2 Ultimate). This VTX is rather focused on normal sized racing quads or planes.
What’s in the box?
Both transmitters come in the usual cardboard box, we are already used to when looking at AKK Technology products. The VTXs are safely embedded in some foam. Besides the transmitter itself you will find a short paper manual, including all the different frequency and band options. Furthermore, AKK includes a MMCX to SMA pigtail adaptor* to connect the VTXs to the usually SMA/ RP-SMA FPV antennas. That’s all you get on both products.
We prepared a short summary table to list all relevant technical data on both transmitters.
|Name||AKK FX2 Ultimate Mini (Intl.)||FX3 Ultimate|
|Voltage Input||7 - 26 V||7 - 24 V|
|Supported Video Standards||PAL /NTSC||PAL /NTSC|
|Connector||MMCX (RP-SMA adapter included)||MMCX (RP-SMA adapter included) & UFL|
|Channels||37 channel***||37 channel***|
|Frequency||5.8 GHz||5.8 GHz|
|Setup||1 Button Setup, OSD setup via FC using Smart Audio||1 Button Setup, OSD setup via FC using Smart Audio|
|Weight||8 g||5.4 g|
|Output Power||0.01 mW / 25 mW / 200 mW** / 600 mW** / 1.200 mW**||0.01 mW / 25 mW / 200 mW** / 400 mW** / 600 mW**|
|Misc.||LED array for channel, band and output power selection,|
OSD setup via FC using Smart Audio,
5V and 12 V voltage supply for FPV camera and aux
|LED array for channel, band and output power selection,|
OSD setup via FC using Smart Audio,
5V voltage supply for FPV camera
|Price (MSRP)||22.36 €*||16.99€*|
***NOT all channels are legal to use within Germany!
** NOT LEGAL TO USE IN GERMANY! CAUTION WHEN SETTING UP!
In the upcoming paragraph we like to discuss the setup process as well as the actual usage of both transmitters. As the FX3 Ultimate* and the AKK FX2 Ultimate Mini are pretty similar in the way you handle them, we won’t duplicate all the contents. Instead we will reference you to similarities.
AKK FX2 Ultimate Mini
Let’s start off with the AKK FX2 Ultimate Mini*. This receiver comes in form of a standard rectangular sized board (36 x 22 mm at a total weight of 8g). The board features two mounting holes with standard 30.5 mm distance. So you could include the AKK FX2 Ultimate Mini in your ESC / FC stack.
Instead of the SMA connector, AKK goes for a small MMCX plug, which you will need to convert into SMA using the included pigtail adaptor*. Right next to the connector you find the single push button to setup the transmitter. The radio module is placed on the front side of the board. The integrated microphone* and the linear voltage regulator on the other hand can be found on the back. The latter is used to power the FPV camera or/and other auxiliary. The pilot has the choice of 5 V or 12 V output. The input voltage ranges from 7 to 26 V. On top of that, you fill find wires for the analog video input as well as the serial Smart Audio signal to setup the transmitter via your flight controller and OSD. Unfortunately, AKK has not provided any values for maximum output power of the voltage regulator. As seen on the new Infinite DVR VTX, the AKK FX2 Ultimate Mini also goes for loose cables with open ends. I can’t stress how much this makes the pilot’s easier, when it comes to building and fixing a racing quad! Nice.
The setup procedure via CleanFlight is straight forward. You will connect the Smart Audio cable to a free UART on your FC*, configure your FC and you can access the VTX OSD* via the standard stick combo. When you are using the button to configure channel, band or radio output power you will have the following options:
- Short press: Cycles through the eight channels of each band (blue LED will indicated switch by flashing, stays solid in Channel 1)
- Press for 2s and short press to cycle: Switch through the five bands (each band has its own red LED indicator)
- Press for 4s and short press to cycle: Switch through the four different radio power levels (green LED* will indicate switch and light up solid on 25 mW setting only)
- Press for 8s: Unlock 1200 mW power settings and non-FFC-conform channels. This setting will be reverted on every power-cycle of the transmitter. (Not tested, as the maximum legal output power in Germany is limited to 25 mW EIRP!)
Please note: AKK* sells an US-version and an international version of this product, which are different in the frequencies that can be used w/o using the unlocking mode.
AKK FX3 Ultimate
The second VTX, namely AKK FX3 Ultimate*, is even smaller as it is dedicated to be used on micro quads. It measures 26 x 26 mm with 20 mm hole distance. The weight comes in at 5.4 g without the MMCX to SMA adaptor cable*. The AKK FX3 Ultimate* also features a second UFL antenna connector, right above the MMCX plug. This allows you to connect even smaller antennas, when it is all about weight and not so much about range. Like the AKK FX2 Ultimate Mini you will connect your FPV gear via soldering to open cable ends. The FX3 Ultimate* features Smart Audio as well as a 5V regulator for your FPV cam. The maximum current rating is set to 300 mA. On the input side you have the choice of connecting any voltage source from 7 to 24 V DC. As the AKK FX2 Ultimate Mini, the AKK FX3 Ultimate also included a small microphone for inflight audio transmission.
The setup procedure is similar to the AKK FX2 Ultimate Mini* as mentioned above. Of course, the better choice would be to go with configuration over serial smart audio, which works flawlessly.
On the field
As the local regulations restrict us from testing with higher EIRP than 25 mW, the following is true for the lowest radio output power settings. Range on both receiver is decent. The picture quality on a RunCam SkyPlus* is clear and crisp. As antennas we have used the TBS Triumph* (see our review on TBS antennas) on the receiver and transmitter. Maximum range on our testing field has been about the usual 500 m. This is no objective test value, but as other 25-mW-VTX performed similarly it can be assumed that the AKK FX2 Ultimate Mini and the AKK FX3 Ultimate* are doing a good job on the 25 mW setting.
Team Black Sheep Triumph FPV antennas* were used for VTX testing.
Thermal management is no problem on any of the two VTXs. Of course, it would be beneficial to not completely cover the radio modules to allow some airflow. During our flight test the transmitters had airflow exposure and have been warm to touch after about 6 minutes of flying. But even on the bench, with no active air circulation the transmission never broke off, neither did picture quality worsen. In the scenario both AKK FPV transmitters* get noticeably warmer, but not as bad as you wouldn’t be able to touch the radio module anymore. The transmitters worked setup on the test bench for over 70 minutes straight without any issues.
We also tested the voltage stability on the linear regulator, which is meant to power the FPV cam. On a constant load of 2oo mA, the regulator on both AKK transmitters managed to hold up the voltage at 5 V (+ a few percent) over the complete input range (7 to 24 V respectively 7 to 26 V).
Time to sum up the monitored behaviours and product handling. The AKK FX2 Ultimate Mini as well as the AKK FX3 Ultimate* transmitter offer a decent built quality. The possibility to connect any in and out coming signals and voltages via solder pads is great. The setup via smart audio is really easy, if you favour the old-school way over the one-button-setup it’s pretty straight forward, too. In the end both transmitters performed very similar in our tested scenarios. Note that the AKK FX2 Ultimate Mini will go up to 1,2 W of radio power, where allowed by law. The AKK FX3 Ultimate* „already“ maxes out at 600 mW. The AKK FX2 Ultimate Mini should also be beneficial for anyone, who needs 5 V as well as 12 V output for their FPV equipment. The price tag on the AKK FX3 Ultimate is around 17 Euros, which solid. For the AKK* FX2 Ultimate Mini you will need to pay around 23 Euro, which also is good value for the delivered performance and features. (Prices regarding direct sales at AKK Technology website, subjected to tax, customs fees, etc).