To those of you that choose to upgrade the vtx in your hawk 5, like I did with the AKK infinite VTX/DVR (in this walkthrough here) I've updated my recommendation for the powersupply. Previsouly I relied on the flight controller's 5v BEC circuit that also powers the receiver and of course the board itself. I've now updated this recommendation to use the VBAT (or VCC) power supply instead assuming of course your VTX can take up to 24V as most modern full-sized VTXs can, including the AKK infinite I installed. This is because the BEC struggles at higher output making the video feed noisy. Over the longer term this is likely to irreversible damage the BEC rendering the flight controller pretty well useless but not before having random failures as a result of the compromised BEC. Picture below is using the power supply from the original VTX - the flight controller's 5V BEC:
So long as you have a VTX that can accept higher voltages, please use the VCC pad to provide power to your VTX alongside the ground pad next to it. This will bypass the flight controller BEC completely and leav you free to use any and all functions on the VTX. This can be clearly seen circled in the image below and on the quad itself
This is a simple change but will clean up your video and place less stress on your BEC. In hindsight this is maybe why some people are struggling with the stock VTX - it may not be the vtx at all, rather that power that is supplying it that is the issue.
My original Hawk 5 VTX install/walkthrough guide is here and other bang for buck modifications I made to the hawk 5 are here.
The Emax Hawk 5 is arguably the best bind and fly quadcopter going as I found in my initial review but can also be greatly improved with a few budget modifications as I wrote about in my blog on bang for buck improvements. I do however see a number of people complain about the stock Emax Hawk 5 vtx however mine has been functioning well. That being said, you cannot adjust setting in betaflight OSD via smart audio or tramp telemetry which is a let down on a 2018 quad. In the interest of sharing I've removed the stock VTX and replaced with one of the larger VTXs currently available (the AKK Infinite VTX/DVR) to prove it can be done.
The VTX I chose is the AKK Infinity DVR VTX. This is very similar to the HGLRC VTX/DVR that was reviewed here. As the name suggests this is a smart audio VTX in 30.5mm VTX with a built in DVR. I chose those for 2 reasons: First it's big. If I can fit this in you can fit anything! Secondly I like the DVR for recording breakup-free footage. For me I like the nimbleness of the Hawk 5 and don't want to weigh it down with a HD Cam. Other key features of the VTX/DVR:
Just quickly I used the following tools and parts in the instructions below:
Please note all the pictures below relate to the install of the AKK Infinite but install should be identical or at least nearly the same for others. I had to remove the buzzer and relocate the receiver for this VTX but depending on the size of the VTX you install you may need to do only one or neither. Follow picture left to right then down. All pictures will enlarge if you click on them.
What did I learnt from the install?
Firstly I can appreciate how Emax has made the most of the space with compact components. If I were to do this again I'd consider a smaller vtx to see if I could get away with removing less components, possibly an AKK FX2 ultimate mini half board or even an AKK nano 2, nano 3 or Oscar's backpack which may allow you to keep the buzzer AND receiver in place. That being said I'm really pleased I installed the DVR unit for extra functionality and did manage to retain a proper SMA antenna mount.
Set up and flight performance
I'm pleased to say that on the very first power up it functioned as expected. All Ineeded to do was to allow smart audio as a peripheral funtion on UART 6 in betaflight and smartaudio (VTX channel and power control through OSD) was fully funtional.
For video signal performance please see below for goggle DVR recording comparing the stock VTX on 25mW and 100mW compared to the AKK Infinite VTX running 25mW, 200mW, 600mW, 1000mW. A quick spoiler: 1000mW was unstable. This is likely because of the load the VTX and DVR units place on the 5v flight controller BEC (which also supplies the camera). 2 solutions here - run at 600mW or below or power the VTX from the VCC pad (picture below) instead of the 5V supply used by the stock VTX. This gives the VTX full access to battery power which is fine since it is rated up to 26v. For me I'll run 200mW maximum since I don't like to overload BEC circuits since it can make weird things happen - FC brown out, flickering OSD etc.
Update December 2018: I now recommend using vbat/vcc to power the vtx as covered here.
Overall for me video performance was comparable. The AKK VTX does however offer greatly improved functionality:
I'd definitely recommend changing the VTX for a different unit that supports Smart Audio if your VTX is not working as well as you'd like, but as you can see above it does take some planning and work. Even if it is working well some of the extra features that can be had on more modern VTXs may be worth the jump especially if you are confident with this type of work. Even if you aren't confident this guide should hopefully help you. AKK tend to make a good budget VTX with a lot of features but you can subsitute your favourite model here easily enough.
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