Long range transmitter and reciever - RC Groups
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Dec 13, 2010, 08:26 AM
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Discussion

Long range transmitter and reciever


I was wondering if anyone could point me in the direction of a transmitter and receiver with the longest range possible(looking for a couple miles). thanks.
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Dec 13, 2010, 09:57 AM
Stinger!
radialarm's Avatar
I found this the other day, but I'm not sure if it will stretch 2 miles. It's what some of the FPV guys are using.
http://www.dragonlabs.net/site/DragonLink/installation
Dec 13, 2010, 12:31 PM
Proud to eat Kraut ;-)
Julez's Avatar
http://www.webx.dk/rc/uhf-link3/uhf-link3.htm
Dec 13, 2010, 01:22 PM
Registered User
ferdous7466's Avatar
hei can any one tell me how i can increase the range of ordinary 2.4 Ghz radios?
Dec 13, 2010, 01:25 PM
A man with too many toys
Are they legal?
Dec 13, 2010, 02:27 PM
Hitec/Multiplex USA
MikeMayberry's Avatar
The Hitec AFHSS system is easily good to 3 miles and has the ability to avoid any interference from other 2.4 devices as seen here:

Review: Hitec Spectra AFHSS 2.4GHz receiver and module (part 3) (6 min 2 sec)
Dec 13, 2010, 03:21 PM
You can call me FANBOY!
Quote:
Originally Posted by RC Man
Are they legal?
Not in the US unless you are licensed.
Dec 14, 2010, 07:52 PM
Registered User
bingo17's Avatar
Would this be for FPV or just general long range?
Good for at least 10km if setup properly:

http://www.dragonlabs.net/
or
http://www.webx.dk/rc/uhf-link3/uhf-link3.htm
or
http://www.immersionrc.com/

@Mike
I used a Hitec Aurora 9 for FPV and got shot down at 1000m so be careful assuming it's good to 3 miles...


Quote:
Originally Posted by TheBatman
I was wondering if anyone could point me in the direction of a transmitter and receiver with the longest range possible(looking for a couple miles). thanks.
Dec 14, 2010, 07:57 PM
Registered User
bingo17's Avatar
What is the receiver sensitivity on the optima's?
or what baud rate does the transceiver use for data comms?


Quote:
Originally Posted by MikeMayberry
The Hitec AFHSS system is easily good to 3 miles and has the ability to avoid any interference from other 2.4 devices as seen here:

http://www.youtube.com/watch?v=7f43mydRdjA
Dec 14, 2010, 08:21 PM
Balsa addiction since age 3
ScottSails's Avatar
Quote:
Originally Posted by bingo17
Would this be for FPV or just general long range?
Good for at least 10km if setup properly:

http://www.dragonlabs.net/
or
http://www.webx.dk/rc/uhf-link3/uhf-link3.htm
or
http://www.immersionrc.com/

@Mike
I used a Hitec Aurora 9 for FPV and got shot down at 1000m so be careful assuming it's good to 3 miles...

Got shot down? - you went into failsafe?.... or you lost receiver power?.... or there was unexplained 2.4 interference (really really unlikely with Hitec)?

I would think that there is something clearly wrong - either receiver, ESC BEC overcurrent (undervoltage), transmitter output, installation, etc. and maybe it should be sent to Hitec for check out?

Scott
Dec 14, 2010, 08:41 PM
Registered User
bingo17's Avatar
It went to fail safe.
Unexplained interference on 2.4ghz - never!
2.4ghz is a ISM band frequency, it is used for all sorts of things including ground radar!
Hitec's Frequency hopping makes it more resilient but one wifi access point transferring data at full speed (using 20mhz bandwidth, even worse turbo mode uses 40mhz) within that frequency range will instantly kill your link - (in this case for instance where the plane was 1000m away).

I do however agree that Hitec is good though, better than others but not the best solution for FPV.




Quote:
Originally Posted by ScottSails
Got shot down? - you went into failsafe?.... or you lost receiver power?.... or there was unexplained 2.4 interference (really really unlikely with Hitec)?

I would think that there is something clearly wrong - either receiver, ESC BEC overcurrent (undervoltage), transmitter output, installation, etc. and maybe it should be sent to Hitec for check out?

Scott
Last edited by bingo17; Dec 14, 2010 at 09:44 PM.
Dec 14, 2010, 09:14 PM
You can call me FANBOY!
Quote:
Originally Posted by bingo17
Hitec's Frequency hopping makes it more resilient but one wifi access point transferring data at full speed (using 20mhz bandwidth, even worse turbo mode uses 40mhz) within that frequency range will instantly kill your link.
Not with any kind of separation it wont. Even with the receiver or transmitter right on top of a standard wifi access point it should completely kill the link. The Cisco access points we use at work might, but a standard wifi AP like a linksys or similar should have no effect on it. And yes, I have tested it. Even tested using a microwave.
Dec 14, 2010, 09:32 PM
Registered User
bingo17's Avatar
What does it matter what brand name of access point is used, it boils down to spectrum usage.
What do you mean "tested using a microwave"?
A microwave oven's radiated energy is confined within the walls of the device so should not really affect 2.4ghz control.
Do you have access to a spectrum analyser to confirm your tests?

Quote:
Originally Posted by chrisf testpilot
Not with any kind of separation it wont. Even with the receiver or transmitter right on top of a standard wifi access point it should completely kill the link. The Cisco access points we use at work might, but a standard wifi AP like a linksys or similar should have no effect on it. And yes, I have tested it. Even tested using a microwave.
Dec 14, 2010, 10:00 PM
You can call me FANBOY!
Because industrial access points in some cases use more power and have higher gain antennas than the wifi routers that are sold for home use. So yes it does matter. Spread spectrum devices are by design able to operate simultaneously, that is the point of being spread spectrum. Can devices interfere, absolutely. But two ISM compliant devices operating simultaneously are not going to cause one or the other to stop working.

You are correct, but it is possible albeit not safe to over ride the safety features on a microwave. Or to cause the door seal to leak enough to be apparent on a spectrum analyzer. It was a PC based analyzer, not as accurate as it could be but well enough to illustrate what was happening.
Dec 14, 2010, 10:07 PM
Hitec/Multiplex USA
MikeMayberry's Avatar
Quote:
Originally Posted by bingo17
@Mike
I used a Hitec Aurora 9 for FPV and got shot down at 1000m so be careful assuming it's good to 3 miles...
So are you saying that some specific equipment you were using shot you down or it just happened as if you were flying a normal plane? While I'm not saying it could never happen, it's just highly unlikely as there have been almost zero reports of a signal lockout with our system. Did you use scan mode to set your channels?

Mike.


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