Yup, that makes sense to me. Probably I am using wrong terminology and kinda confuse you guys since I’m new to that stuff. OSD should suite my needs, for sure. I don’t really need to observe telemetry info much, as long as I have control over my plane.
My goal is to build ~50km range fpv fixed wing. And the main criteria for me is to have VTX and receiver working on such ranges.
I’m kinda confused why telemetry is usually comes together with what we call receiver since telemetry suppose to actually transmit data. But that becomes making sense to me as well.
Yeah this is what was probably confusing me the most. Telemetry assumes data transmit to the receiver, while same time we are talking about telemetry to be a receiver for control.
And I actually plan to work on longer range flights (~50Km), so I guess I would need something more powerful. But as I figured the telemetry data isn’t that important for me as long as plane receives control instructions and I VTX work.
The main requirement is to control my fpv fixed wing on range ~50km. Telemetry data observation isn’t as important to that moment.
Receiver (Rx) is primarily the thing that receives the command signals from your transmitter (Tx) and forwards them to your flight controller. Newer Rx/Tx technologies are able to transmit telemetry back from the flight controller via your receiver to your transmitter, so you can get live telemetry information on your transmitter’s screen and/or trigger alerts. Transmitter is the thing you hold in your hands to control your drone.
Thanks, that makes sense! So when RC guys mention “telemetry” they usually assume that it would work in both directions right? In common telemetry module works as receiver and transmitter?
As far as I see it, the term “telemetry” describes the process of “sending data back to the pilot”. You can get minimal data through OSD, or more data either through the RC link backwards or with a dedicated telemetry link (like this for example) parallel to RC.
If it works in both directions is depending on the type of the telemetry link.
OSD is one-way down; through the RC link is depending on the protocol used, it is possible but not all links support it (Yaapu over CRSF for example doesn’t); dedicated telemetry links usually are two-way.
An AAT is not absolutely necessary. What is good is a higher location and sensible antennas. And of course an RC system that goes this far (from old to new with own experience: EzUHF, Dragonlink, RFD, Crossfire, ExpressLRS).
Yup, dedicated dirrected antena will definitelly be used for that. Although interesting point around mobile cell service, do you have any examples in mind? Would be much appreciated
In our case higher location is not always possible. So the directed antenna will be used
For the RC system. I was looking around pros and cons, and for the longer ranges they are almost always recommend DragonLink instead of Crossfire or ERS, since DragonLink systems provide longer range on same power levels from transmitter. Definitelly a question for another topic, but if you have experience for longer ranges what would you recommend?
I have already flown over 50 km with all the systems mentioned. Currently I would prefer an ExpressLRS system (Radiomaster Bandit) on 868/900 MHz to all others.
I don’t have any personal experience with it, I just read it here on the forum.
This looks like worth a shot (Hi Reinhard ^-^):
For more examples search the forum for “LTE telemetry”
Dragonlink also supports full (two-way) MAVLink telemetry together with the RC link. ELRS currently doesn’t support MAVLink, if I’m not mistaken (please correct me if I am). Crossfire theoretically does but I didn’t have much luck with it last time I tried it.
@Indie_Hacker mentioned that only normal telemetry is planned. ExpressLRS is good for that. With the branch “mavlink-rc” Mavlink will also work, but it will take some time. LTE is also a possibility.
Dragonlink is not bad, but 3.5 years no more updates and Mike doesn’t have a programmer for it anymore … the project is dead if you ask me.
I would take ExpressLRS, it is also much cheaper and can be bought at any time.
The easiest way is with analog video on 1.2/1.3 GHz. With digital video (Walksnail) I haven’t gotten over 40 km so far.
Setup tips for 1G3 video can be found here. You will soon realize that the selection has become small. I can only recommend equipment from RMRC and antennas from TrueRC.
That’s good. At least we have a very clear requirement: ~50km long range flight, mainly focused on RC/Video link.
When Video link is broken, it’s hard to recover, especially long range, even if analog VTX when turn a round the antenna is blocked (partially blocked) by battery or companion computer etc.
When video link is down, it’s impossible for FPV pilot to operate the drone. Then if telemetry is OK, we can still navigate the drone(RTL or smartRTL is NOT that smart actually, maybe some expert with carefully setup for rally points might to the smart thing) from MP or QGC and know where it is. If crash, we can know where it crashed ( last know position will be send out by telemetry.
That’s the advantange of dual link control. And of course, low power telemetry or PCB antenna??? is useless for such long range flight.
– EDIT
BTW, mostly VTX works on 5.8G/2.4G/1.2G etc, and RC link works on 2.4G/915M/868M etc. Some known telemetry module works on 433M/868M. In the same situation, low frequency is much more likely to transimit far away.
Maybe switched to 4G LTE module is a good choice for civilian usage: vdeo and telemetry( for long range) Ah~~~~ that’s the DJI drone.
Very good points. I will dive deeper to learn more about MP and QGC stuff, and probably re-consider my requirements regarding telemetry.
First I thought I could do LTE. But now I figured is probably not an option for me due to bad coverage in the area of flights, most likely there is no mobile signal at all
Ah~~~~ that’s the DJI drone.