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!
thanks for having me here. anyone know of any ways to build an amplifier that would achieve this but using discrete components and ICs only? I have a project that asks us to build amplifiers this way. Any good tutorial would be welcome. i am just not sure on what amount of power would boost the signal to say 2km.
me gustaria saber si este amplificador (Wireless 2W 2000mW 34dBm Broadband WiFi Amplifier ) sirviria en mi dx6i por q tu idea es muy Buena sencilla y economica me gustaria saber si me puedes ayudar con eso y algun concejo extra seria bueno
gracias por tu tiempo
me meImage not availablePhotos not available for this variation
"So do you then run a cable from the Tx to the boost so you can still operate easily?
How long did you know your antenna had to be? Or is it the same the length as the antenna on the radio?"
Yes, I didn't show a pic of the cable hooked up and running. I have a 20" widescreen LED TV that mounts up in the dash of my Saturn, then I sit back in the drivers seat with the booster feed cable hanging out the window. The feed cable is 30ft long, so plenty of play, and lots of separation from the video RX tower, which has a 50 ft feed cable.
One feature I really like on the A9, is that it asks you if you want to transmit when you power it on.. It was not transmitting in the picture. After hook up, I hit yes, and the green light on the booster starts flashing rapidly.
I went with a 6dbi antenna, because it is about as high you want to go with a high gain omni, without getting a bad null over your head. The booster antenna has about 3X the gain of the stock 2db antenna. The vertical beamwidth for this antenna is 28 degrees, which is fine for long distance flights. With higher gain omnis (greater than 6db), the vertical beam gets lower and lower. Therefore, they are not well suited for aerial FPV.
For those asking in earlier posts, these 1 watt amps work great with my Hitec Aurora 9. I got a good quality, USA made miltary grade UFL to RP-SMA cable. WAY better quality than those Chinese ones with the tiny, fragile micro-coax. I drilled a hole through the module and the case and ran the wire inside the case. Then I pulled out the whole stock antenna assembly and epoxied a plastic washer into the top of the radio, with the RP-SMA connector coming out of the top. It came out so good, the radio doesn't even look modified with a 2db ant on it. Also, no external wire anymore.
I made a fiberglassed wooden mount, on a tripod, that holds a 5000mah 7.4v LIPO battery, 3A BEC, and batt monitor. The booster has a large fiberglass 6db omni on top, connected by a thick, 12in low loss cable..
With a 30 ft RG174 cable running to it, from my car, the TX pwr is attenuated just right, and the boosted signal output looks beautiful on my spectrometer. I am also using a BEC that puts out 5.5 volts, so hopefully it last longer and is more reliable. It barely gets warm while operating for long periods, and draws about 1.3 watts from the battery.
Works beautifully. I have had the plane out nearly 5 miles and I still had perfect control AND I never lost telemetry. Remember, it is made for 2-way communication and the booster has a built in LNA on the receiving end, for noticeably improved reception.
I'm building a Bixler now with RSSI indicator on the screen and a Hitec compatible RX with RSSI output, so soon, I'll report back just how strong the signal is at a distance.
Overall, all great results so far. The A9 and AFHSS technology really work excellent in combination with these boosters.
Comments
hi,
thanks for having me here. anyone know of any ways to build an amplifier that would achieve this but using discrete components and ICs only? I have a project that asks us to build amplifiers this way.
Any good tutorial would be welcome. i am just not sure on what amount of power would boost the signal to say 2km.
regards
Jordi Munoz hola.
me gustaria saber si este amplificador (Wireless 2W 2000mW 34dBm Broadband WiFi Amplifier ) sirviria en mi dx6i por q tu idea es muy Buena sencilla y economica me gustaria saber si me puedes ayudar con eso y algun concejo extra seria bueno
gracias por tu tiempo
Futaba 8J has 2 antenna inside can any one explain how to attach amp to it.
Comment by William Wegenast
"So do you then run a cable from the Tx to the boost so you can still operate easily?
How long did you know your antenna had to be? Or is it the same the length as the antenna on the radio?"
Yes, I didn't show a pic of the cable hooked up and running. I have a 20" widescreen LED TV that mounts up in the dash of my Saturn, then I sit back in the drivers seat with the booster feed cable hanging out the window. The feed cable is 30ft long, so plenty of play, and lots of separation from the video RX tower, which has a 50 ft feed cable.
One feature I really like on the A9, is that it asks you if you want to transmit when you power it on.. It was not transmitting in the picture. After hook up, I hit yes, and the green light on the booster starts flashing rapidly.
I went with a 6dbi antenna, because it is about as high you want to go with a high gain omni, without getting a bad null over your head. The booster antenna has about 3X the gain of the stock 2db antenna. The vertical beamwidth for this antenna is 28 degrees, which is fine for long distance flights. With higher gain omnis (greater than 6db), the vertical beam gets lower and lower. Therefore, they are not well suited for aerial FPV.
OK,
So do you then run a cable from the Tx to the boost so you can still operate easily?
How long did you know your antenna had to be? Or is it the same the length as the antenna on the radio?
I got this booster on ebay, a couple years ago. Seems to be the exact same model sold on DIY-D.
"Comment by William Wegenast
@Flyin High In AC
Nice description!!
This is great! Care to share a link where you got your booster?"
Here's some pics I just took of my A9 setup, described above.
@Flyin High In AC,
Yep , some photos/pics of your setup is appreciated. Any 2.4v RC rig should work with this booster in theory.
@Flyin High In AC
Nice description!!
This is great! Care to share a link where you got your booster?
If you have the time, show some pics, but your description is great.
For those asking in earlier posts, these 1 watt amps work great with my Hitec Aurora 9. I got a good quality, USA made miltary grade UFL to RP-SMA cable. WAY better quality than those Chinese ones with the tiny, fragile micro-coax. I drilled a hole through the module and the case and ran the wire inside the case. Then I pulled out the whole stock antenna assembly and epoxied a plastic washer into the top of the radio, with the RP-SMA connector coming out of the top. It came out so good, the radio doesn't even look modified with a 2db ant on it. Also, no external wire anymore.
I made a fiberglassed wooden mount, on a tripod, that holds a 5000mah 7.4v LIPO battery, 3A BEC, and batt monitor. The booster has a large fiberglass 6db omni on top, connected by a thick, 12in low loss cable..
With a 30 ft RG174 cable running to it, from my car, the TX pwr is attenuated just right, and the boosted signal output looks beautiful on my spectrometer. I am also using a BEC that puts out 5.5 volts, so hopefully it last longer and is more reliable. It barely gets warm while operating for long periods, and draws about 1.3 watts from the battery.
Works beautifully. I have had the plane out nearly 5 miles and I still had perfect control AND I never lost telemetry. Remember, it is made for 2-way communication and the booster has a built in LNA on the receiving end, for noticeably improved reception.
I'm building a Bixler now with RSSI indicator on the screen and a Hitec compatible RX with RSSI output, so soon, I'll report back just how strong the signal is at a distance.
Overall, all great results so far. The A9 and AFHSS technology really work excellent in combination with these boosters.
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