I promise I'll keep this one short. We are forever taking antennae on and off our quads and goggles as we arrive and leave our flight locations. I'm guilty of being too eager to get in the sky and not tightening my antennae correctly thereby leaving a poor connection to the active element on both the quad and goggle ends. Using a spanner is not a fix I'd recommend as it is easy to over-torque and damage the antenna or mount.
The fix here is really easy and I got the tip from my favourite VAS antennas which all include a plastic knurled grip (now I know why). Using a knurled grip that sits over the hexagonal drive on an SMA-style connecter allows you to get a better grip and more torque on tightening whilst avoiding over torquing as above. To put this another way - using these grips allows you to get the right tightness every time - good for the best connection and it will also help them coming loose in flight.
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:
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.
I've now had my FullSpeed RC Leader 120 for 1 year and have completed a bench review and flight review. After hundreds packs and many replacement props I thought it would be good to look back at what I've changed to keep this up to date and fun because at it's core, the Leader 120 is still an excellent quad and sits in a class of it's own as a ready to fly 2.5 inch quadcopter.
The core of the quadcopter remains the same - original ESC, original flight controller, original 1104 7500kv motors. The bearings on the motors are a little noisy now but no detriment to flight. especially with the modern filtering available on beta and butterflight.
My original review quad was kindly provided by Gearbest but is also available now from Full Speed RC's own website. Full Speed is a little more expensive but offers an excellent customisation service. Speaking of Full Speed the proprieters are pilots and test their products a lot before release - it's no accident they have good products. The Leader 120 is available at Gearbest here and FullSpeed RC here. It sells for anywhere between $100 and $130 depending on sales, discounts.
So what have I changed in the last year?
The Leader 120 ships with a VM2751 CMOS AIO cam and while ok for a whoop I don't think it does the Leader 120 justice given the speeds you can move at. I cannot emphasise enough how much an improvement the FPV system makes. Choose any camera you like, mine happens to have an HGLRC elf as that is what I had available at the time. Now there are many options, my personaly favourite is the Arrow Micro Pro - a 4:3 CCD cam which has an excellend image and can often be had for $20. For the VTX I personally use the Fullspeed FSD-TX200. This has proven to be an excellent long term reliable vtx that mounts easily to the back of the camera. There is no smart audio but then again you can get it for only $11. If smart audio is a must for you I'd recommend FullSpeed's new FSD-TX600 or the AKK FX3 ultimate.
I've made a full article on the install here but with one recent change that has made this much more robust (see picture below).
You may have a receiver already but if not I'd recommend the Fullspeed model. They are less than $10 each and are available in DSM or FRSKY. More importantly they weigh less than 1g so help preserve the lightweight aspect of the Leader. Another thing I really like about the Fullspeed nano v2 receiver compared to the FRSKY XM is the fact that RSSI (control link strength) is enabled on aux 5 by default for immediate use in betaflight OSD. Frsky XM and XM+ receivers need to be flashed for this functionality. The Fullspeed FRSKY Nano V2 is available from Fullspeed RC, Banggood or Gearbest.
This is a personal choice. The stock 2.8" Kingkong 2840 props are fine but power hungry due to weight and pitch on 2s and almost unusable on 3s. Probably the best alround props is the Gemfan 2540 (@Bangood, @Gearbest) which offers the benefit of grip as in the stock props but at a much better efficiency with marginally more noise as reviewed here. Another option is the Gemfan 3025 twin blade (@Bangood) trimmed down as detailed here. These offer better efficieny again with but with less top speed. I got 9 minutes of flight when using a new 950mah 2s on these props... full review here.
Now running betaflight 3.4.0 which is release candidate at time of writing. Best features for me? Improved filters and much wider PID tuning window. I especially like the throttle limit options that are tied to rates as I think all I get between 90-100% throttle on 3s is noise with more current draw and very little increase in power. I believe my leader originally came with 3.1.7 Low pass and dynamic filtering has improved dramatically since then.
1 year on the Leader120 is surprisingly relevant with a few minor mods. Don't forget that Fullspeed have made minor tweaks throughout the life of this quad - 20a esc upgraded to 28a, FC upgraded with better board layout, UART access and improved BEC. No one has really got a comparable lightweight 2.5" ready to fly that compares - the shift to 1105, 1106, 1107 and even 1108 motors on 2.5" have changed flight characteristics and durability for the worse. Even the Skystars Bolt 120 which looked like Heir to the throne with 4s capbility felt like a porker to fly.
Enjoy this quad if you have it and upgrade at you leisure or not at all. Plenty of options on this community favourite.
Parts mentioned here:
Leader 120 Camera and VTX upgrade
The Leader 120 is my favourite micro quad but manufacturing to a price point has meant that although not uncommon, the camera and VTX leaves something to be desired. I found that although it handles light well for an AIO camera, it is poor compared to a CCD camera meaning flying in an out of dark areas can be challenging. Additionally the VTX is limited to 25mW so total distance before video breakup is not fantastic, especially around trees or other obstacles.
I used a micro CCD camera (in this case the camera from the HGLRC XJB F428 Elf) and the new Full Speed TX200 VTX as a way to replace the AIO camera/VTX supplied as standard. A full review of this setup is here so that I can use this blog to give details of the install specific to the Leader 120. Update: Gearbest sell a clone of the micro swift which is identical to the HGLRC Elf - the Furibee 1672. This performs just the same as the other micro CCD cameras - micro swift, arrow, HGLRC elf. Update 2018: The foxeer micro arrow pro is now the best value and performance micro CCD camera at around $20
For my first attempt at the install please see the captioned pictures below:
Unfortunately with this setup I had digonal lines in the video feed that were made worse when the quad was armed with increasing breakup when throttle was increased. Since this VTX will happily accept 5-17v I supplied power from VBAT rather than using the 5v BEC circuit on the flight controller. This immediately fixed the issue for the minor inconviniece of having to solder additional wires to the VBAT pads. This did however offer the advantage of less stress on the BEC circuit and less risk of brownouts as a result, especially when running on 200mW transmitting power.
You can read my conclusion in the review but to summarise a micro CCD is a must have on the Leader 120. Having to use Vbat due to noise on the flight controller 5v circuit is a minor inconvience but the improvement on signal compared to the AIO camera, even on 25mW is really impressive and running on 200mW opens a whole lot more flying opportunites with much better penetration though trees for example. The additional depth the VTX adds to the camera (meaning the top standoff cannot be fitted) is mildly annoying for the leader 120 but realistic. I thought it would be hard to top the Eachine VTX03 but the tidyness in piggybacking to the camera and ability to do it's own 5v regulation wins it for the TX200.
Update 2018: I forgot to mention this does rely on being held in by wedging the camera between the sideplates but since then I've found a better free solution below:
I trimmed a standoff by approximately 5mm and used longer screws to torque the frame together. This is much stronger and more secure than my previous install. Note: the caddx cameras are a different shape and you may be able to install without trimming that standoff
On my lightweight x2 EYAS (updated build link here) build I use an Eachine TX01 All In One (AIO) Camera/VTX. Stock, these come with a basic Circular Polarised (CP) antenna that works well but is heavy and more importantly: not very durable. This is because the antennas are left fairly exposed on micro quads.
More often now, AIO camera/VTX modules have linnear whip antennas that are much more durable, lighter and still get you about 90% of the performance of the CP antenna - much more practical in the real world for micro. Linnear whip antennas are actually a sleeved dipole where the outside sheild of the co-axial cable is grounded. The exposed centre transmitting signal is then exposed for a VERY specific length that should be tuned to 5.8GHz which in most cases is 12.9mm for a 1/4 wavelength of 5.8GHz.
Albert Kim did an excellent video here and found that most whip antennas have the wrong length. Great! Easy to cut if they are too long, hard to fix if they were too short. Well the 10 spares I had were too short!!
To fix this I tried the trick that my flysky FS82 and RX2a pro receivers use - a basic monopole antenna. This is a simple 28AWG wire (or any other small gauge wire) soldered directly to the signal line of the VTX with nothing on the ground pad. The wire is then cut to precisely 12.9mm, then heat shrunk over the top to relieve stress from the joint. Result:
What I see now is that the main reason for a dipole whip is to elevate the signal out of the frame where the AIO camera/vtx is enclosed. However, when the camera is mounted high like on my EYAS X2, it does not give any benefit and so the ghetto monopole antenna works just as well.
Quick follow up 10 months later and this continues to work well. I've now done the conversion to 4 AIO cameras with no ill effects. I've even done this on a FullSpeed tx200 piggyback vtx (review here) that is attached to the back of a runcam swift and no longer snag and lose the dipole. A really useful mod that has stood the test of time