Posted by Jordi Muñoz on December 2, 2009 at 2:00pm
I love my Spektrum Dx7 and my 2.4Ghz JR XPS9303 and i refused to trade its solid rock performance by a 72mhz radio just to increase range of my FPV/UAV. So in collaboration with my friend JB we find out the cheapest and secure way to amplify the signal, it even works in some Futabas and virtually with any 2.4Ghz radio, but some modifications are required. Lets see some options:-Spektrum Dx7 this is the cheapest solution for a very reliable 2.4Ghz radio, i used it for about a year and i never had any signal glitch (unless i fly beyond 2000 feet). The problem with this one is that you have to modify it, you need a SMD to U.FL adapter, drill a hole in the side of your radio and just connect and screw the adapter, no soldering required. If you have more than 5 hours of experience with Legos your qualified to do this job. Then you just need to connect the booster. The one in the picture (middle) is already modified.-If you have the awesome JR radio but is 72Mhz you can buy the Spektrum 2.4Ghz module and just insert it in the back of your TX, personally this is my favorite setup. It's a good deal because includes a $99 dlls receiver for free! Note that JR TX alone cost around $600 dlls, but you can get it for less, i got mine for 300 bucks with Spektrum Module included on R/C Groups =P. Remember you are looking for the JR XPS9303.If you have one of the fallowing Futaba radios:7U Series Radios8U Series Radios8J Series Radios9C Series Radios9Z Series RadiosFN Series RadiosYou can just go and buy the Spektrum 2.4Ghz module, easy and with no hassles. It's also a good deal because includes a $99 dlls receiver for free!
One of the advantages of the Spektrum receivers is the build in diversity system, you can even buy one with 4 satellites like this one, or buy a super tiny, tiny setup like this one, or the traditional one.The diversity is crucial to have a reliable link when you are flying far away, also Spektrum has a receiver for Carbon Fiber airplanes (Carbon Fiber blocks RF signals).The idea is to have the best reliable hardware with an SMA connector and the SMA extension cable, after that you are ready for the final step: Get an amplifier. But we are talking about a few hundred dollars here, if you get the weakest one of 100mW it will cost you around $150 dlls. This is not pocket friendly in my point of view. So again our Asians friends come to the rescue, after making some research around the net I've found on eBay and a home Wireless Amplifier, so i decided to give it a chance and i bought it for 60 bucks including shipping! Wow that's a good deal! The one i got is this one.Note that the amplifier needs 6Volts to work, you can get a cheap 6V power regulator from here and just make the adapter. A 3 Cell LIPO is enough to supply it for a long time.
After receiving the AMP i did some tests, here are my results:Before using the amplifier, i was able to fly around 3000 feet away (~1 km) using a 900Mhz@500mW Video transmitter. I never lost the video signal, only the radio link...Using a 1.3Ghz@1Watt Video transmitter i was unable to fly more than 2000 feet away (~600meters). So the 1.3Ghz Video transmitter reduces my 2.4Ghz Spektrum range...Then i got my cheap Asian amplifier and using a 2.4Ghz Patch Antenna i was able to fly around 2.6 miles (4.18Km) away without a single glitch, but i was unable to continue because now my video was causing me problems, hehe!Not bad at all! Honestly i don't need more than 2 miles of coverage, is really a long way for an EasyStar. In conclusion the maximum range for my setup still unknown, but the range achieved is more that 2.6 miles and the +2 extra miles of coverage gained for less than $100 dlls is really a good deal for me!
Now just remember this:-The range will be different in other setups.-Never turn on your radio without antenna.-Never turn on the Amplifier without antenna.-Note that in some country's this amplifier may be illegal.Thanks for watching!
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@Jordi - sorry for the question on the side, but I'm remembering posts in the early ArduPilot days of mixing/matching comm links - 72MHz RC, 900MHz XBee & 2.4 GHz video. If you've switched to 2.4 GHz RC link, what are you running for XBee and Video comms? I run 2.4 GHz RC alongside 2.4 GHz XBee, but have never really done enough to make sure I am not/will not get interference.
By the way, this booster setup rocks.
Ok, it can't be the 6v regulator (measurements are good). The replacement pig tail cabel can't be it because of the fact, wen i put the antenna straight on (without the booster) it will work properly. It has to be the booster, but on the network router it will increase the range enormous... The only think i can imagine, is that the combination don't mach between the rc tx and the booster :(
I had tried to place an url of the booster i have purchased but i don't see him. Here it is for the second time, wen it works! www.dealextreme.com/details.dx/sku.28711
I have the same spektrum dx5e, and i'm trying to get it work.
I have drilled a hole to fix a pick tail cabel in it. (no soldering required) i'm using a 500 mw booster
As 6v regulator i use the same as shown above.
But it doesn't work !!! When i switch to the range check function, i can nearly walk 10 meters away....
Maybe its the range check function ? i haven't try to check the range without the range check function on.
Dear Jordi,
All of our indoor booster (1W & 500mW )are saled with warning lables from Taiwan. I can't not confirm whether other agents remove the label.
After serious disscussing with our manager,it's our mistake for lable.
We should change the lable form "Input power more than 50mW that Power Amplifier may be broken down" to "Input power more than 100mW that Power Amplifier may be broken down".
Because we already upgraded input power of booster,but we were negligent of lable. Jordi,I really feel sorry about that.
Dear Jordi,please kindly test it again. The 500mw booster can accept input power 5 ~20 dBm.
If you could use the booster 500mW,please remove the lable to help your sales.
And we will ship the booster with correct or ship them without lable (If you request.) lable for your next order
If not,we will find solution for following.
I will try my best to help you.
Please feel free to disscuss with me.
Sorry for any inconvenient caused.
Best Regards,
[Erased] Huong guahn chun...
Disctrict Sales Director
But anyway the difference in power gain from 500mW to 1Watt is 3dBm (from 17dBm to 20dBm) is almost nothing, in reality your are not doubling your distance range, what does the difference is open your receiver and solder the best coaxial cable you can find of 50 ohms, with the less distance possible, without using connectors in that way you can gain up to 40% of range. I have friend that used to work for the government, i don't who is he, and i don't know his real name, anyway he gave me coaxial cable used for a satellite project and it REALLY improved the range of the system. SO the secret is use the shortest cable possible (mine is about 8 inches long) and soldered it from the antenna to the receiver (NO connectors).
In the case of your Spektrum 2.4Ghz you want to use the worse cable and a lot of connectors to attenuate the signal ;-)
thanks for the answers , because i'm stuck to build my uav :
900 mhz is taken by the gps tracking device ( Xbee xsc powered )
2.4ghz by the Radio link ( Multiplex cockpit 2.4ghz )
so for the video i have only two choice , 5.8ghz and 1.3ghz , the 5.8ghz is pretty expensive and not so powerful ( 300mw max ) , so the 1.3/1.2 ghz is my only option.
Hello Tycinis, yes that is correct. Without the AMP and the antenna i can't get more than 800 meters (about .5 miles) with the 1.3Ghz. Also take in consideration that i was using the high gain 14dBi patch antenna, thats helps a lot.
Comments
The link will disappear or show up as longhand text if done incorrectly.
First select the URL from the source and then moving to the comment area, highlight a word in the sentence like maybe the company name, etc, then press the link icon in the bar, and paste the URL in the drop down window that opens. Works everytime that way.
By the way, this booster setup rocks.
I had tried to place an url of the booster i have purchased but i don't see him. Here it is for the second time, wen it works!
www.dealextreme.com/details.dx/sku.28711
I have the same spektrum dx5e, and i'm trying to get it work.
I have drilled a hole to fix a pick tail cabel in it. (no soldering required) i'm using a 500 mw booster
As 6v regulator i use the same as shown above.
But it doesn't work !!! When i switch to the range check function, i can nearly walk 10 meters away....
Maybe its the range check function ? i haven't try to check the range without the range check function on.
some pictures.
IMAG0326.jpgIMAG0327.jpgIMAG0328.jpg
I hope someone can help me..
Greets, Olivier
Dear Jordi,
All of our indoor booster (1W & 500mW )are saled with warning lables from Taiwan. I can't not confirm whether other agents remove the label.
After serious disscussing with our manager,it's our mistake for lable.
We should change the lable form "Input power more than 50mW that Power Amplifier may be broken down" to "Input power more than 100mW that Power Amplifier may be broken down".
Because we already upgraded input power of booster,but we were negligent of lable. Jordi,I really feel sorry about that.
Dear Jordi,please kindly test it again. The 500mw booster can accept input power 5 ~20 dBm.
If you could use the booster 500mW,please remove the lable to help your sales.
And we will ship the booster with correct or ship them without lable (If you request.) lable for your next order
If not,we will find solution for following.
I will try my best to help you.
Please feel free to disscuss with me.
Sorry for any inconvenient caused.
Best Regards,
[Erased] Huong guahn chun...
Disctrict Sales Director
In the case of your Spektrum 2.4Ghz you want to use the worse cable and a lot of connectors to attenuate the signal ;-)
900 mhz is taken by the gps tracking device ( Xbee xsc powered )
2.4ghz by the Radio link ( Multiplex cockpit 2.4ghz )
so for the video i have only two choice , 5.8ghz and 1.3ghz , the 5.8ghz is pretty expensive and not so powerful ( 300mw max ) , so the 1.3/1.2 ghz is my only option.
thank you for testing , you help me a lot.
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