Long Range RC

[pmarek]

Hello,

Just started working on an MAV project. I don't need to make it very autonomous; basicaly it can be operated all the time by a pilot who's getting video from the plane. My only problem is, can I somehow increase usual range (~500m) of a standard RC system to at least 1km?

Sorry if that question was already brought up here; I did not find anything on that topic :confused: .

Prez

[Blue Sky]

Most standard full range RC systems are good for 2+ km.
-Dave

[JettPilot]

A good RC system like a JR, is good for 5 KM ......

JettPilot

[treehog]

Range can vary a lot from 500m to 5km depending on factors

A low to ground as in two feet of the deck model planes will be lucky to operate much more than 200 metres average probably 500 metres max assuming flat ground no hills tress building etc blocking signal as the signal risks to de distorted from things in the ground like iron in the clay or wire fences or salty water which can recuce signal strength

High up verticall the signal might be 1km easy for good sets and possibly 5km with correcet usage line up antennas L recieving anntenna etc



I opt to reasearch solutions that will return the plane as quickly as possible to recieving range if it strays outside the tranmision range or auto land it if cloud or fog interupts normal vision flying (I dont mean drinking and flying double vision issues )
Also terrain avoidance which could help me not to hit the hillside while doing DS

There also exists ways to extend range of radio recievers with antenna gain eguipment

lots of solutions debates exist on search usualy for large gliders which theraml at 3 to 5kms ranges


Ralf

[tron]

Hi all, you can use new equipments RF of 869-928Mhz. Range up to 50Km. :D


What about the rc link?: 869Mhz RC&FPV system of DMD. TX=500mW (+27dBm), RX sens=-99dBm, Patch 15dBi.

At 9.38Km i received -82dBm (view on OSD). Easy Glider.

For additional info: http://www.rcgroups.com/forums/showthread.php?t=799087

regards, :)

[problah]

N00bie question, what about a 2.4ghz radio? Would it require some type of a booster, and are there any available?

[sectrix]

I'm hoping to build the same thing. The control system I thought up was to use 2 radio modems (Digi XTends) and 2 microcontrollers (Parallax). One microcontroller would read and encode input from your controller and transfer it to the sending modem, which would transmit to the plane. The receiving modem (on the plane) would transfer the received data to the microcontroller, which would decode it and drive the servos. It would take a bit of work (you would have to write firmware) but in exchange you get up to 65 Km line-of-sight range, 256 bit encryption, FHSS (Frequency Hopping Spread-Spectrum) capabilities, error correction, 115 Kbps uplink (room for telemetry data, if you like) and a bunch more. Don't know the rules of radio in Scotland, but they only come in 900 MHz.

[dmgoedde]

...you get up to 65 Km line-of-sight range...115 Kbps uplink (room for telemetry data, if you like).

For XTend, the stated range drops for the higher data rate of 115 kbps. The Max range of 50-60km is for 9600 bps. Also, for the max range, high-gain antennas are needed. No problem on the ground station side, but a Yagi isn't practical on the plane for weight and pointing reasons.

Still, stated range for XTend 900 with rubber ducky antennas is around 20 miles LOS. I'll know soon enough what pans out in the real world, as I have made a breakout board to connect an XTend to the "IMU" port of AttoPilot Beta (see attached pics).

If data is sent ASCII, then you are right, you probably need 115kbps. For the RC portion transmitted from ground to plane, an nmea type format like this for 4 servos at 50 Hz would take about 10kbps alone:

$1289,1251,1846,1439*2D<CR><LF>

That is 25 bytes * 50 Hz * 8 bits/byte = 10,000 bits/s. (This is a quickie estimate)

If you send the data as binary instead of ascii, then same info transfer would consume less bandwidth.

[matttay]

This is a cool application for smartphones: http://www.comvu.com/

Install this app on your UMTS smartphone, stick the smartphone in your airplane, and then you get streaming video at about 150 kbps pumped to a webpage. In real time, you can go to a webpage on your PC or another smartphone and see a 2 second delay of what your phone sees. Not good enough to fly by, but the range cannot be be beat.

Note that a 150 kbps stream is about QVGA at 15-25 frames per second. Not great. However, operators are rolling out video calling that will run at higher bit rates. Expect low-latency VGA at 25 fps to be available from your cellphone in the next 18-24 months.

PDA devices shoudl be considered more for UAVs. With 4GB of storage, 128Mbytes of RAM, integrated displays, a UMTS modem with data rates in excess of 1Mbps, WLAN, bluetooth, GPS receivers, self-contained battery + power supply, 3MP cameras...there's just too much good stuff in a modern PDA to not find a way to be useful in a UAV. All of that in a package that weighs 150g.

[zlite]

PDA devices shoudl be considered more for UAVs. With 4GB of storage, 128Mbytes of RAM, integrated displays, a UMTS modem with data rates in excess of 1Mbps, WLAN, bluetooth, GPS receivers, self-contained battery + power supply, 3MP cameras...there's just too much good stuff in a modern PDA to not find a way to be useful in a UAV. All of that in a package that weighs 150g.

Absolutely. We've open sourced a complete navigation and imaging autopilot for Windows Mobile (now working on an GPS-enabled iPaq). Not the greatest camera in the world, but you can't beat the range ;-)

The thinking was "cellphones already have virtually all the hardware you need of a navigation-only autopilot. Let them do the work of systems integration, and turn the autopilot into a software-only problem". Now looking to port the VB code to newer Windows Mobile versions.

It's here (http://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A729)on DIY Drones.

Also note that the Pict'Earth guys have a Noikia N95-based onboard imaging software package (http://pictearthusa.com/software.html), too.

[thomasscherrer]

maybe look here too:
http://www.rcgroups.com/forums/showthread.php?t=905915

[hoysome]

you just brought back a thread from 8 months ago to advertise your new transmitter? your thread is more than enough :)

[Scotty Love]

I would love to find a way to fly my B2-spirit 2 or even 3 miles out. I have a real nice live video feed but now I just need to buy somthing that will extend the range of the bomber. Can some one please tell me what I need to buy to get that kind of range? I have a $500 budget if that helps.

[Tarro]

WOW, you want to fly 2 or 3 miles is that even possible? :eek:
I will do a search if I can and find an answer for you, wait maybe you can do a search as well? :D

[airmcn_3]

WOW, you want to fly 2 or 3 miles is that even possible? :eek:
I will do a search if I can and find an answer for you, wait maybe you can do a search as well? :D


More then possible ;)

[dmgoedde]

More then possible ;)It's even moore thin pausable (you mis-spelled 'than'. ha ha )

[airmcn_3]

It's even moore thin pausable (you mis-spelled 'than'. ha ha )


Sure did!!!! :D

[johnorama]

my last employer uses a Futaba Tx modified to bypass the antenna and send the signal to a 50W amplifier for a backup controller of a UAV. It used commercially available components and I guarantee it cost less than $500. It has safely operated UAV's out to 70 miles. The trick is that you need to have an equally powerful transmitter on the aircraft to get your video. Also, how do you do frequency deconfliction with everyone else flying RC's within 70 miles of your location.

I recommend trying high gain directional antennas, first. I believe Eagle Tree now has an antenna auto-tracking capability with their new hardware.

[jtprouty]

You'll need to watch the FCC regs since power output on our authorized RC channels is limited to under 1 watt (more like .75 watts.) and modification of the RF section is not supposed to be done. They even went as far as saying we can't change crystals to change frequencies (that's why FMA won't sell you crystals for your TX.)

[johnorama]

You'll need to watch the FCC regs since power output on our authorized RC channels is limited to under 1 watt (more like .75 watts.) and modification of the RF section is not supposed to be done. They even went as far as saying we can't change crystals to change frequencies (that's why FMA won't sell you crystals for your TX.)

Good point. And let me add, I never insinuated that increasing the power out of a Futaba was legal. I know we often received interference on 72 MHz and I can't help but to think how many R/C planes flown by others that we crashed for them. I did mention that this was a previous employer and I left as soon as I had the opportunity because of practices like this.