Long Range RC Radio Project with 2.4 Ghz 
There is a few different ways to get more range with an RC radio like the UHF LRS system developed by Thomas Scherrer and the DragonLink. Both systems have more then 3-7+ miles of range. Another option is using a J-pole antenna (FM only) in place of your standard antenna giving 2-3 miles of range. These are all good ways to gain more range but for me since I mostly use 2.4Ghz RC radios those aren't options. After reading that some FPV pilots have used 2.4ghz patch antennas and/or WiFi boosters with good results I decided it was time for me to give it a try. On recommendations I purchased a Wifi Booster on eBay for under $50 and a 2.4ghz patch. This booster will increase the RC radio power output from 100mw up to 1 watt which if this works will increase the range from 3000 feet to 2 miles...maybe even more. The patch will be used on my antenna tracking station so it will always be pointed at the aircraft for even better range. More on this in the Ground station pages. For the RC radio I will be using my Futaba 9C with a Spektrum 2.4ghz module. This should make this mod easier since I won't have to remove the stock antenna or use a interface cable (SMA to U.FL) from the circuit board like with Spektrums DX6/7/8 users do. So for this all I have to do is remove the factory antenna from the Spektrum module and put the booster with 5db attenuator in-line and then reconnecting the factory antenna to the booster.....easy :).
I purchased a HobbyKing UBEC that outputs 5-6 volts placed on the 6 volt setting. This is needed to power the WiFi booster which operates on 6 volts. I connected the BEC to the RC radio battery (12v) to get the power. In the future I will be adding a master battery power switch so I can only power the booster when the RC radio gets power....THIS IS IMPORTANT!!!....Do Not Power Up your RC radio with the booster off and/or with antenna disconnected. This will ruin the RC radio. Radios must have an antenna connected anytime it's on!!! and this info is in your RC radios manual so the same goes for when there's a booster attached....if the booster is off, then it will be just like not having a antenna connected. To keep this from happening always power up the booster first or do what I'm planning on doing by adding a master battery switch this way everything will be powered on/off at the same time. Another concern is the booster has a warning label warning not to input more then 50mw or damage to the booster may result. The Futaba/Spektrum radio I'm using has 90-100mw output so to reduce the input I will add a in-line 5 dB attenuator (3 to 6 dB can be used) that will decrease the input power of the Spektrum module adding protection. Note: Some FPV pilots doing this booster mod have reported that the booster works fine without a attenuator because it's not powered 24-7. This maybe true but a attenuator is Highly Recommended!!! when using short extension cables (under 18") and cheap insurance at less then $20. Without a attenuator you risk ruining your RC radio and/or the booster. Also if you use a 50 ohm SMA extension cable longer then 5' to 10' feet it will act like an attenuator so don't use both together...one or the other. W
With this mod and using the radio for over a year now... I feel more secure about my RC radio link. Even though I don't do much long range flying and this mod isn't really long range like other systems but it's nice knowing I have a more solid link at 6000+' ...this I really enjoy.
A DX7 Bottom and DX8 (top)
The DX6/7/8 have a U.FL connector at the PCB which needs to be adapted
to a male RP SMA connector so it can connect to a 2.4 ghz WiFi Booster in-line with the antenna.
The DX8 is powered by a 2s lipo so I use a Y cable from the battery to power the UBEC
that in turn powers the booster with 6 volts.
A Futaba 9c with Spektrum 2.4ghz module can have the WiFi booster
connected without purchasing a U.FL /SMA adapter.
Everything just hooks up in-line with the stock antenna.
Want to find these items?
Since links may only work for a short time try Searching for the these terms on eBay and the net.Attenuator: "
07-02750 Sertek 5 dB Coaxial DC - 4GHz 5dB
" eBay
Links:
ComputerGeeks.com Dealextreme.comForum link :
RCgroups.com How-to
DIYdrones link
This mod also works with surface/ground radios. A good idea for FPV driving of larger
RC trucks like the HPI Baja 5b,5t and 5sc.
CNChelicopter has a 2 watt 2.4ghz booster listed on there site for long range.
Just keep in mind a 2watt booster is illegal for use in most countries so check your laws.
Some reports are that 2 watts can give 5-7miles and even more with a 2.4ghz patch antenna.
Update: 3-24-2010: After testing I gained a easy 2500 more feet of LOS range.
Before adding booster the 2.4ghz radio lost contact around 3000-3500'
and now with booster it still had a good solid link at 5500 feet LOS. My
RTH was not working so I did not risk going any further. More long
range flight testing to come.
Update: 1-14-2011: Still working fine and no issues (38 flights). Range is over 1-1/2 miles at 7200 feet tested.
Update: 2-10-2011: Boosted DX8 with same 1 watt booster. Tested and working Fine. Even the telemetry is reporting with the Spektrum data transmitter TM1000 .;