AKK FX3 Ultimate review: The most fully featured 20mm VTX available

The AKK FX3 Ultimate VTX from AKK

AKK bring out new products at an amazing rate, particularly VTXs which are their core product. They tend to go through stepwise rather than stepchange product development where they make gradual improvements to already good products - the opposite of 'if it ain't broke, don't fix it' which is a say I HATE. Best of all they do this at an extremely competitive price which is possible only because they tend to sell direct rather than go through a third party. Don't worry they ship at zero cost or very little and are available on Amazon. I've already reviewed the excellent FX2 (30.smm stack) here and have installed the original FX3 (20mm stack) here on a 4 inch lightweight build.

Features as listed
The product I am reviewing today is the AKK FX3 Ultimate which builds on the AKK FX3 as mentioned above. Key features are:

• 25mW, 200mW, 400mW and 600mW power switchable - a 200mW increase in maximum power from the regular FX3
• OSD configuration using Smart audio - it has smart audio and yes it is compatible with all versions of betaflight
• 7-24V input with 5V output - up to 5 direct input or of course any voltage if you power via FC
• Support Pit Mode - very low power output that is useful for setting up at races.
• One button frequency and power setup - Support if you do not use smart audio
• MIC - same as the FX3 however audio is much improved (will get to that soon)
• MMCX and UFL connectors. It has both!!!

The install
I wanted to do a rebuild of my FlexRC Komori (original build here) as an efficient longer range quad so this was the perfect product to use - full control with smart audio, 20mm stack mounted for extra security and up to 600mw power for improved range. Having audio on longer range is highly underated too since you can hear if anything is suspect with your props or motors long after you've gone out of range of direct sound.  To summarise install was painless. I prefered the solder pads to the connectors on the FX3 and the stack mount means I can get a super reliable and secure mount without reverting to doublesided tape or cable ties. I love having the option of UFL or MMX in this size. See below for images and specific commentary on the install - click to embiggen.

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The antenna
Like my tooth fairy and floss 2 builds I've used the Realacc UXII Stubby RHCP MMCX-J 5.8GHz 1.6dBi Super Mini Short Antenna here. It is a $6 right or left handed CP 1.6g antenna that is plugged into and supported by the MMCX connector if the frame allows. For me these are a super clean solution - no long pagoda or cloverleaf stalks or even dipole whips that need extra supports. Even the AXII ufl requires more room and a 3d print support. Reception is 'good enough' given the benfits I get. Other connectors and formats are available.

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Performance
I fly with Aomway Commander goggles (review here). Reception is good enough for me but not a good as some of the stand-alone modules that are available for Fatshark goggles. I found the signal to be clear and static free when in line of sight and got fairly minimal break up with behind trees which lessened as I ramped the power up. I used the Aomway Clover for omni directional and the RealAcc patch for directional (review here).

I can confirm there are absolutely no issues with Smart Audio on Betaflight 3.3 and 3.4 and adjusted bands, channels and power without issue. The vtx it replaced from the origianal Furibee X140 (review here). This VTX transmitted video well be had no audio, no smart VTX, a very awkward button/LED interface and a direct solder connection only for the antenna. The FX3 not only brought more transmission power options but also added a lot more convience - I would choose to never change channel or power previously now I frequently change to suit the conditions. Also the option of using UFL is excellent because for micros this is typically a more suitable connector given space constraints. I'm just lucky that the Komori frame has the stack mounted close to the back for the UXII antenna with good clearance.

See below for a DVR of my flight running 200mW.

AKK pricing strategy?
From what I can tell AKK run on very tight margins akin to RCX motors at MYRCMART. This means that they only sell direct since there is not a lot of margin available for resellers and so the prices are very low for the feature set. For example the retail price of this unit is only $18. Nothing gets close to this price for the feature set. Furthermore at the time of writing, AKK have a sale on, meaning it is available for only $16

There is a sale on at time of writing that is actually pretty good. They have these on every 3 months or so.

Summary
The AKK FX3 Ultimate is simply the most feature packed 20mm vtx available at time of writing. It is also the first 20mm sized VTX to offer 600mW maximum power and options for MMCX AND ufl connections. It is simple to install and maintain with direct solder connections and the standard stack size mound means it is very simple and secure in your build. I can happily recommend this for new build or replacing an older VTX that doesn't have the full feature set you want.