There are quite a number of different OTG FPV receivers available. Those are receivers which you can connect to your phone via USB and record your FPV feed - you phone is basically your DVR.
Your phone has to have the UVC driver enables and has to support OTG, so make sure that your phone meets those criteria (all newer android phones have at least OTG support). There are a couple of apps in the Play store that will check for you if your phone has the UVC driver enabled.
You are not limited to using those receivers on your phone, you can also attach them to your computer and use them basically the same way you would use a webcam. Or to phrase it differently: any program capable of using a webcam will also be able to use this receiver as a video input.
You can use your USB OTG FPV receiver to live broadcast yourself flying when using OBS for example.
I intend to use those receivers in an upcoming project and decided to get a selection of different available brands and models, just to make sure that my upcoming project will work flawlessly with all those different devices.
The OTG receivers all look very similar and I suspected that the internals might actually be the same in all of them.
First of all you can find those branded by Eachine on Banggood. There are three different versions:
Then there are two Skydroid branded options on Banggood:
I also found multiple other brands on Amazon which basically looked exactly like the Skydroid’s so I did not bother ordering them.
The Eachine ROTG01 is the most basic version, it comes with one button and one RP-SMA connector. Interestingly (I have three of those) all of them seem to come with a chipped inductor, as you can see on the image.
You long press one of the buttons and auto-scan is invoked, it will then automatically lock to the strongest available signal. You can also short press the button to increase the frequency in small steps until it loops around the frequency band and starts from the beginning.
All of the receivers cover a frequency range from 5645MHz to 5945MHz.
Allthough they seemed to have the same size from the product images, the ROTG01 is actually the smallest of the bunch, it is just 33 x 55 x 10mm. All of the others measure 41 x 60 x 11.5mm.
The Pro version - the Eachine ROTG01 Pro - has all the same specs as the Eachine ROTG01, apart from the size and a second button allowing you to switch the frequency up or down. This makes setting the frequency manually quite a bit easier. This is exactly the same as the Skydroid version.
The Eachine ROTG02 has two RP-SMA connectors, this is actually true diversity - meaning it has two separate receiver modules and is switching between both of them, depending on which one has the better reception. This is the same as the Skydroid True Diversity Receiver - which as the name suggests is indeed true diversity.
All of the devices identify themselves as a Arkmicro Technologies Inc. when plugged into a computer. They also all provide the same video resolutions - 640x480 or 352x288 @ 60, 30, 15 or 5 FPS - at least with Linux the device can be basically seen as a webcam. The optimum settings in my opinion are 640x480 @ 30FPS.
I was able to run 3 of those receivers on a single root hub at 640x480 @ 30FPS. When using the lower resolution and only 15FPS I was able to run 5 of them on a single root hub (after hacking the Kernel module a bit). If you want to use more than 3 on the highest resolution your computer will need to have more than one USB 2.0 root hub.
Except for the ROTG01 all of the other devices also offer an audio device when attached via USB, meaning that you should also be able to record audio, in case your VTX supports this - none of mine does, so unfortunately I could not test this.
The power consumption is also very similar with all of them, although they are all specced slightly differently, all versions with one receiver consume about 200mA @ 5V and the ones with two receivers consume 300mA. This is still well within the USB 2.0 specifications.
The receivers all come in a nice tin box which also contains a micro to micro USB cable. Except for the ROTG01 all of them do additionally come with a micro to USB C cable. You will also get a linear antenna with all of them - the diversity versions of course come with two linear antennas.
Be aware that if you want to change those linear antennas - which you probably should, at least on the diversity models - you will need RP-SMA antennas.
You can use all of those devices stand alone (without attaching them to your phone or computer), they provide audio and video output and you can power them externally from 5V, you will need a small 4 pin plug to do so, this was not included with any of the receivers that I got.
The auto-scan version works really well - I would even say, that it works better than on most goggles I have used the auto-scan function on. I would recommend to power your quad and set auto-scan for your frequency without any other quad powered. This makes sure that you don’t have to push the button like crazy to switch to a different frequency (which can be a pain in the ass, especially on the ROTG01).
The latency is unfortunately quite high on all of them (and it is the same latency on all of them. Some people say that the ROTG02 has lower latency than the ROTG01 which I cannot confirm), so I would not recommend to fly via this feed, although it seems to be very tempting simply using your phone as FPV monitor - I cannot recommend that at all.
The feature set of all of them is basically the same. The Eachine ROTG01 is the cheapest option, that you can get for around $13. I have a hard time recommending a specific version. I think it depends: If you are just looking for a cheap DVR or a solution to let someone ride along, go with the ROTG01, no need to spend more than necessary.
If you are planning on actually getting some additional antennas, to replace the stock linear antenna, you are probably the guy who would also be interested in going with the ROTG02 simply because it has diversity - but with $21 it also does cost quite a bit more.
I would not really recommend the Skydroid version, since it does exactly the same as the Eachine, but is a couple of dollars more expensive.
Those USB receivers are a great and cheap way to have someone ride along with you or simply have an external DVR. The setup is really easy to use: once you got the app installed you plug the receiver into your phone and you are basically good to start recording.
On Amazon I found those receivers under a couple of different brands (ie.: FUAV), but under the hood they are all completely the same - one of the three base versions described above, most likely the same features as the ROTG01 Pro or ROTG02.
Chris is a Vienna based software developer. In his spare time he enjoys reviewing tech gear, ripping quads of all sizes and making stuff.
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