Diatone Roma F4 LR REview and Diatone's attention to detail

The Diatone Roma f4 LR is the most recent full release in the new category of 4 inch micro long range quadcopters following on from releases by Flywoo, Iflight, GepRC and Eachine. It is available in a version with the DJI Caddx Vista and a cheaper version with analogue video Basic specs are similar to the others but I'll get into the detail in this review which separates the good from the great.

The 4 inch micro long range market is well established now with a solid Formula that has been developed by the very clever Dave Cledon (his youtube channel is here). In this review I am looking at Diatone's offering - the Roma F4 LR of which mine is equipped with the DJI-Caddx vista and Nebula V2 camera although most findings will be applicable to the analogue version as well. Diatone have always had great attention to detail including a solid tune (as I found recently with the larger Roma F5 here) so keen to see how this translates on the F4 LR.

A closer look at the specs

• Camera: CADDX Nebula Micro V2. This is the oft-maligned DJI digital camera from CADDX in its second iteration. Diatone are running this one out and will be replaced with the much improved Nebula Pro. This can be easily swapped out but I'll talk about performance of this camera more in the review itself.
• VTX: CADDX VISTA (LHCP Antenna). Same ubiquitous Vista unit but with Diatone's own antenna that mounts the active element high above the quad for best image transmission without obstruction from the rest of the quad
• FC: MAMBA F405DJI MINI. Revision of the ultra reliable Mamba F405 Mini to allow direct connection to vista unit with a clean power supply
• ESC: MAMBA F30MINI 8BIT. Upgraded version of the original reliable 20x20mm ESC from Diatone, now 30A rating rather than 25A and 2-5s instead of 2-4s. This ESC is over engineered for this quad so I would expect it to be reliable
• Motor: MAMBA 1404 3000KV. A little more kV than the standard 2800kv than Dave Cledon specified but not a huge amount. Even if rating is accurate the difference in negligible.
• GPS: BN-180. Very basic GPS unit that I've had good success with in the pass when mounted correctly. In this quad it is well isolated by way of TPU frame extention/mount.
• Drone Weight：157g. Surprisingly this is actually a little light than the Explorer LR's 163g even though it uses aluminium camera protection. The difference may be due to the increased weight of the DJI camera on the Explorer compared to the nebula camera on the Roma.

A closer look at the build itself
Diatone aren't usually first to market in new categories for quadcopters because they usually tend to refine the product a little more before they release. This can be seen when you take a close look at the Roma F4. Firstly the camera housing on the frame is made from 2 pieces of CNC cut aluminium. Rather than just looking cool (and it does) it offers much better protection from collision, including the standoff at the bottom. You'll also see the number of mount points which gives you options to change to other cameras like the longer lens DJI cam without comprimising on protection or catch the mount in view. 

Aluminium camera protection is functional and looks DAMN good

Multiple mounting hold options for the camera means you can use cameras with any lens length and still get good protection without frame in view.

Frame design itself is deadcat meaning no props are in view which I think is very important for DJI FPV quads, particularly one that is meant for long rang cruising - an issue that both the Eachine Shadow Fiend and Iflight Chimaera missed a beat on in this category. Elsewhere, 3mm thick arms butt-up against each other to minimise the risk of frame resonance and a staggered frame means plenty of room for electronics whilst keeping the centre of mass low. Interesting to note there is space for a whoop-style AIO ESC/FC which would be an interesting option to save some weight in future if needed. Minimal use of 3d printing for antenna holders (VTX, GPS and immortal T) help to keep weight down. Upper and lower rear decks are kept minimal to encourage cooling of the vista unit and help keep weight down as well.

No doubt about this one being a deadcat frame with the front and rear arms pulled well back. Great for cruising but for freestyle it will be a little more awkward

Staggered frame with the lower rear deck sitting a little higher leaves enough room for cam and stack while retaining the low profile stance

Check out the "wings" underneat the ESC - this will allow you to use a 25.5mm AIO board which I may look at in future. You can also see individual arms are butted up against one another to add stiffness. Lastly the rear lower deck is minimalist which allows for cooling of the vista unit

Decent TPU print to allow the GPS to hang out the back for best reception. I got 10 satellites locked within 1.5 minutes on first power up. Also houses and immortal t antenna from TBS or FRSKY

Very simple antenna mount for the vista unit. I like this location to keep this transmission signal away from gps and control link receivers.

In terms of the actual assembly, there is typical Diatone quality here - all screws are well tightened with loctite where appropriate. There is a large stack of spare screws, connectors, straps and other key spares as well as nicely prepared manuals and an exploded chart of the frame. Soldering is top notch and cable routing is secure and robust. Clearly the eye for detail has carried on from design to execution here.

Typically clean Diatone soldering and cable management

Even the screws have had attention with a nice looking milled finish one the outer edge

Diatone have done well to squeeze a decent size capacitor in there and have done a good job adding insulation to the legs to reduce the risk of shorting

Betaflight setup
I'll get straight to the point - there is very little to do here except your usual customisation which for me is:

• Rates - I like low rates on a cruise machine like this (expo down from 0.7 per axis to 0.5)
• Aux switches - set up your arming plus any other features like beeper and turtle mode
• OSD - I just used the stock OSD this time which was set up pretty well
• GPS rescue mode - In the failsafe tab I chose failsafe mode 2 as GPS rescue since it was disable by default.

Betaflight version is 4.2.4 on mine which is the very latest release at time of review. The quad is well customised - PIDs, ports, RPM filtering, PID and gyro loop rates (all the tricky stuff) are well taken care of. Did I mention attention to detail? Here is the stock diff if you ever need to revert.

diatone_roma_f4_lr_factory_diff_beta_4.2.4.txt
File Size:	4 kb
File Type:	txt

Download File

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Like any other Vista unit you'll need to register via the DJI software and update to the latest firmware which of course is all automated. Move to FCC mode where legal and allow 50mbps for that rich image in your goggles.

Flight performance
With the customised PIDs this quad flies really niceley. You can go a step further and tighten up the dynamic filters as per the betaflight tuning guides since RPM filtering is present on this setup. Tune is optimised for 4s which is pretty much the only cell count I would recommend for this quad - motor kV is too low to support 3s with any real control authority.

Compared to the Eachine Shadow Fiend I reviewed recently this is much more ready to fly and requires no messing about - just wire in your receiver of choice and go. There are no props in view so the feed in your goggles will be clean as will the DVR you record. I only record for my own use so DJI DVR @ 50mbps if perfect for me but if you wish to share then this quad will easily support a naked gopro or the new SMO camera. I wouldn't recommend a camera heavier than this.

These are definitely down on raw power compared to a 5 inch or powerful 3 inch but the goal here is smoothness, and efficiency rather than maximum power. I'd liken it to running 4 or 5s on a quad designed for 6s from a power standpoint. Props and motors are well matched, the small 1404 sized stators giving you just enough authority to make you feel in control but the not so much that it loses it smoothness. Definitely a good match for this type of quad.

Can you freestyle? Yeah, rolls, power loops, split s are all fine just bear in mind it won't be as able fast to make corrections and you'll need more time to pull out. It's certainly not what this quad was designed for but of course it can manage them. Bear in mind that the frame was made with weight control in mind rather than maximum durability - freestyle quads crash a lot whereas this is not really the case with long range cruisers.

The one downside of this quad and all other quads in the 4 inch micro long range class is their ability in moderate to heavy wind. They do get moved around in a sidewind because they have a large prop area and low weight and in a headwind the lack of power can make progress slow. Tailwind is great though 😂😂. 

​Batteries and flight time and weight
My battery of choice for flights was a CNHL ministar 4s 650mah which offers about 6-7 minutes of flight for an all up weight of 243g with strap and battery pad. 4s 850mah will get you closer to 10 minutes but will take the weight out to 266g. If you really want long flight time then consider a 18650mah pack which thankfully are now available as an off the shelf item. These will give you over 30 minutes of flight time if that is what you are after. Here are a few packs that are pre-made with the right type of cell - the sony VTC6. Since they are all made from the same cells, check to see the best price when you are ready to purchase

GepRC 4s VTC6 18650 3000mah pack

URUAV 4s VTC6 18650 3000mah pack

AUline 4s VTC6 18650 3000mah pack

Flywoo 4s VTC6 18650 3000mah pack

BN-180 GPS unit used here

GPS Performance
Shortly after release of the Roma F4 LR, The Flywoo Explorer LR was revised to include shielding for the signal cable that linked the FC to the GPS unit. Supposedly the Vista unit emitted radiation that interfered with the GPS - this was the hypothesis behind why the GPS unit was slow to lock and so shielding would minimise this issue. Diatone also jumped in on this and has started shipping with a shielded GPS cable as well as offering a free cable shield to those who put early orders through. Well I haven't run the shield and I've had no issue whatsoever with GPS lock, in fact this has been my best GPS quad yet - 12 satellites after less than 2 minutes on my very first plug in! It's so good in fact I'll actually take these same settings in betaflight and apply to my other quads too. Note: when running GPS, make sure you plug in your quad FIRST before goggle and transmitter. This allows you a little extra time to get a solid GPS lock before you are ready to fly. 

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Nebula V2 Camera Discussion
The Nebula camera that Caddx made to pair with the vista unit came in for a lot of criticism because of the poor image compared to the DJI camera on the regular vista. Small improvements were made to the v2 model as used in my quad but it was still inferior to the DJI Cam. Speaking from personal experience though, I'm still new to the DJI FPV space and to me the image even with the Nebula cam does look great compared to ANYTHING analogue, simply no comparison. That view may change when I use the DJI camera more but for now I am more than happy to leave it in place. At time of writing though Diatone are currently running out the Roma F4 units with a these Nebula V2 cams like mine (update: they have now sold out on Banggood) and are replacing with the Nebula Pro. The nebula pro from review this far looks to be much improved - comparable with the DJI camera so this breakout section can be ignored once these are commonplace.

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Comparison and Recommendations
Clearly the micro long range 4 inch quads are a class in and of themselves and so difficult to compare to other classes due to their focus on maximum efficiency and flight time at the cost of power and durability in particular. But then again they do long smooth flight VERY well, a matter of choosing the right quad for the right job.

When it comes to comparing the Diatone Roma F4 LR to other quads in the same class (i.e. micro long range) then I would say this is one of the best if not the best offering there is at present. Diatone's attention to detail is outstanding - from frame design, to spec, to spare parts, to betaflight  tune and even right down to the fasteners they have used. This translates into an easy and convenient flight experience - practically everything has been thought of and in case it hasn't Diatone has an EXTREMELY responsive customer service team that is also very active in the community - check out Diatone's Facebook group if you don't believe me. Best of all they manage to do this at a very competitive price - the Roma F4 is the most price competitive of the bunch at present. I will exclude the Eachine Shadow fiend from this list because the lack of current and voltage detection is simply unforgivable on a long range quad.

As a result I am happy to recommend the Diatone Roma F4 LR as the best of the bunch in regards to the Micro Long range quads - the design and execution is top notch. Also consider the Flywoo explorer V2 which is an updated version of the original quad that defined this class that seems to address some of the shortcomings of the first version albeit at a higher price point the the Diatone version reviewed here.

Note: the Roma F4 LR is also available in an analogue version that has a very low entry price point. The VTX used is there new 400mw version and is very clean as reviewed in the Roma F5 here. Camera is the budget but reliable Runcam Nano 2 which keeps the cost right down.

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