antenna tracker on plane/multirotor?

[octodreamerFNG]

wasn't sure where else to post this but i figured this was the only place it fit...

looking at the headplay goggles and was thinking about an antenna tracker and it got me thinking... as small as the 5.8 antennas are, why not mount a small pan/tilt tracker with a helical on the multi-rotor to always point at me instead?

the thinking here would be a diversity type setup with a cloverleaf for close range or crossovers but after that you'd have a laser beam of signal pointed at you no matter where the craft is.

which got me thinking (and yeah i know this goes against the whole LOS concept)... couldn't you have a tracker on both ends therefore giving you crazy range?

back in the day i did a lot of "war-driving" and messing with wifi. a couple friends had built themselves pringles can "can-tennas" and we got the idea to use them on a camping trip to extend my friends wifi from his rooftop on a hill to a to our campsite miles away.

so i'm fairly certain two helicals pointed directly at each other can work to give you extended range, just not sure how it translates over to RC 2.4 or 5.8 applications.

there's lots of long range systems available out there in the lower frequencies but i wonder if anyone has ever toyed with the idea of two trackers talking to each other using 5.8?

thoughts? ideas?

and hey while we're at it... (and this is where it gets real silly)

lets say i'm in a location with a ton of tall trees but i wanted to send up a multirotor to explore around... obvious problem being as soon as i get outside of my little cone of vision of the sky... i loose connection.

so then would it be possible to have a craft that only serves a purpose of bouncing a signal from a craft back to the ground? like a long flying multirotor with lots of mah that just hovers 200 feet or so over your head and uses 2 different bandwidths to talk to both you and the craft and act like a relay system.

so for example the plane would have a tracker sending 5.8 back to the hovering multirotor, which then uses 900 to send it back to the ground to my ground station?

is any of this possible or am i missing something?

if so... what kind of range could you get without having to buy a high dollar long range system?

 

[wilmracer]

So... on your second idea...

check this out. It is pretty much exactly what you're talking about. I have no details on how he did it, but he does outline his setup pretty well in the video description.

https://www.youtube.com/watch?v=DczTSYZ2kYE

 

[ZoomNBoom]

The second idea, or relaying the signal is indeed "often" done; the most common use for it is if you have 5.8 Gh integrated in your goggles, but some other band on your plane. Then you put a relay on your ground station so you can still fly untethered. But you can even use the same band, say both 5.8 as long as you separate the channels far enough. Also, instead of using a quad, you might even explore the idea of using helium/hot air balloon or a tethered blimp or something.

btw, wilmracer's video is awesome!

As for the first idea, Ive been wondering the same; in theory it should work, however the benefit is probably limited. If you use a tracker on the ground with a very narrow high gain antenna, you can already achieve crazy ranges, adding one on the craft too will just make it so much heavier and its not going to be easy to make it accurate and fast. But dont let that stop you from trying .

 

[Craftydan]

For a tracker-to-tracker video link, the on-board platform will need some sort of steering controller -- a 360 servo would be enough for movement, but which way to point? you'd either need some sort of RSSI beam steering (heavy and complicated) or a VERY good GPS and Magnetometer to calculate which way to point it, and some way to tell it the coordinates of where it should point. Neither solution is particularly good for their own reasons, but it's possible to make them work.

It also has a significant technological hurdle the base station doesn't -- the "target" antenna on the base station will only move quickly in angle if you're already up close (and your diversity should kick in on the omni antenna at that point). On the airframe, your target antenna will *rapidly* move in angle every time you yaw.

The airframe also has the distinct disadvantage at range, since the target position at the ground station becomes more and more a 2-D position as range increases, it remains a 3-D problem on the airframe. If you use wide beamwidth directional antennas ( a 3-turn helical is nearly hemispherical, but not exceptionally high in gain) you could get away with this, but you could be severely limited in bank angle on a more directional antenna. A tilt gimbal controlled to maintain level could help with this, but that increases the antenna's motion envelope quite a bit, and would negatively impact signal while flying high around your base station -- there's no practical method for diversity-omni on your VTX side.

Downlinks like these have been done, though I'm not aware of any modern commercial applications.

As for the repeater quad, if you watch his follow-on Vid, you'll find he used two band to establish the link (5.8 between repeater and ground, 1.3 between camera quad and repeater), and used omni antennas on all the video links:

https://www.youtube.com/watch?v=eonNhMcpDOc

The significant hurdle he accomplished wasn't maintaining the video signal across the repeater, but controlling two airframes simultaneously from the same radio. In that respect, Naza makes good flying robots and without the reliable position hold they provide he wouldn't have had a chance.

 

[octodreamerFNG]

great answers guys, thanks for entertaining my musings.

happy to see i wasn't totally nuts.

 

[SalemFlyer]

Your instincts were heading you in the right direction, it's just the details that get us.

Made me think, though...as FPV grows, and things like 250 racing grow, I could see the need for some sort of repeater system along a course. Basically, have the equivalent of those wifi range extenders blanket the course with coverage. Probably easier for such things as time trials, where one person can be bound to the system at a time. Different than your concept, in that it relies on stationary infrastructure, but in static situations like pipeline monitoring, or farming, hey...could work. Dynamic situations will always be trickier.

Then again...

Wireless data is getting faster and faster. Would it possible, in theory, for someone to route the FPV feed and tx/rx through say a 5g (or whatever is the newest standard...) wireless data network? They make arduino shields that do 4g and take a sim card. So, it isn't like the tx is "hostile territory," nor is the rx. Hell, flash your ESCs while you are at it.*

Anyone have any insight into that side of things? Would latency be too high?


*Never flash your ESCs while in mid-air. Gravity happens.