JR 12x 2.4ghz TRANSMITTER
+ FIT A 2W (2000mW 33dB) Wi-Fi BOOSTER
(for the sensible level of power output that we SHOULD already have on 2.4ghz to safely control fast or distant RC models)
+ HOW TO CONVERT THE UK’s DSM2 JR 12x, TO DSMX or DMSS EASILY!
This page is generic, in that the info here applies to ALL 2.4ghz RC systems and increased range for both FPV as well as avoiding being ‘shot’ down!
You can be unlucky on 2.4 and find areas of your flying site that have “dead” areas, or parts where other 2.4ghz users have directional antennas or dishes, that cross your flight path.
Or just congestion due to Wi-Fi, Bluetooth in cars, phones, laptops, other RC users etc. Especially in or near a town or city.
The info here will allow you to modify Futaba, Spektrum, or any other 2.4ghz RC TX to give you 10 to 20x the mW of RF output power. And increase range by some +4 times
Many have done this, its not new, and well proven and safe – IF DONE CORRECTLY!
The booster means Increasing it from the inadequate EU’s 100mW, or US (+others) 200mW to some 10x or 20x this power output level. A better, safer, 2000mW output power. Or more than 4x the signal strength at any point in space.
This simple booster modification simply means about plus 4x the signal strength at every point in space that you would normally fly in. This actually gives about 3.5 to 4 miles safe real world reliable range under typical airborne conditions. Without dead spots or other 2.4ghz congestion affecting you,
A typical 2.4ghz RC system, usually has just 0.7 to 1.1 miles range in OPTIMUM CONDITIONS 1000m Quoted by Spektrum and JR. Often its much less. When actually tested you may get a fraction more or very MUCH less, on different days or places.
THIS 2W (2000mW) BOOSTER GIVES 4X THE MAX RANGE
But more importantly, you have a signal that’s better than 4x stronger for a more secure RF link all of the time. To get over the mass of 2.4ghz ‘noise’ mow present, at any given flying distance.
Unlike all the mass of miss-information, and scruffy conversions with cables hanging everywhere, and extra antennas added etc, (as can be found all over the web), it can actually be done very simply, safely, accurately and neatly. So that it both looks tidy and works reliably – just like a stock transmitter.
And then you can just use your transmitter as normal and forget all about it being “boosted”… Its just a better, more reliable link, a safer, longer range RC system. Especially in or near built up areas.
Because 2.2ghz Radio Control, (and Wi-Fi etc) all negotiate channels and can use more than one channel at once or the same channels at the same time there is really no risk to your fellow flyers. Or at least there any risk in theory.
I LOVE THIS JR 12x TRANSMITTER!
It FEELS right, its all MAGNESIUM shell feels good. The front, the back, the sides are lightweight rigid metal. Its solid. And it feels perfect in the hand, and none of the newer Futaba, JR or Spectrum stuff compares. In comparison they LOOK like what they are. Cheap Chinese made radios. They look and feel plastic, because they are. All creaky, and nasty and styled like a star wars toy or something. This just works, is solid, and has beautiful build quality both inside and outside. Unlike all the cheap stuff its also packed with quality components. This is no empty cheap plastic box.
I wouldn’t have any of the ‘new’ sets as a gift after using this. So I decided to convert this 12x to DSMX (not technically available in the UK) and give it far more output power. The ultimate transmitter for me!! As of summer 2013, you can keep all the modern plastic junk!
I wasn’t about to wreck my very expensive JR 12x Transmitter!
So if I wasn’t completely sure about doing this, and doing it properly, I wouldn’t have attempted it.
This conversion uses the STOCK 2dB gain 2.4GHZ antenna that the transmitter came with, and the same single transmitter battery I always use (a LiPo 2600 mAh with 2 voltage reducing diodes in this case), A neat permanent solution. As you can too!
And no dangers, no extra switches, no voltage regulators, no extra batteries etc. No wires hanging all over to rip out and nothing in the way of your fingers. Just 4x the stock signal strength/range.
THIS BOOSTER MODIFICATION MAY NOT BE TECHNICALLY LEGAL IN YOUR COUNTRY…
Its not in mine either. But there are already thousands of non hobby users, using these Wi-Fi boosters, and bigger ones too, with HIGH dB gain antenna systems. They are used in homes, farms, factories, boats, cars, etc all over the US and EU. for long distance wireless internet access, video links, for security systems/alarms, with many having 10s of miles of range and much more RF power than this conversion. You cant put this stuff back in the box! Its all out there and in popular use. You are FLYING in this mass of non legal, over used, 2.4ghz confusion. So if you cant beat them, join them!
THIS is just 90 feet (25 meters) high according to my OSD system on my Quad! Just 90. There must be hundreds of Wi-Fi, Alarms, wireless networks, laptops, baby alarms, toys, phones, other Bluetooth devices in this picture. Not to mention microwave ovens, and a microwave radar on the maritime college nearby. Your RC craft can now now see them all!
At say, 500 feet, it can see all the 120,000 inhabitants houses and flats and factories of my town.
SO YOU BETTER GET A BIGGER GUN!
When 2.4ghz gear first appeared the 2.4ghz *free* band wasn’t really used heavily.
And early 2.4ghz gear was only ever intended as cheap park flying RC gear for toys. Now it is used by EVERYTHING! 2.4ghz is a bad choice for a radio control link anyway, as it is absorbed by walls, grass, moisture in the air, suffers from line of sight control like a light bulb (almost) and null spots due to multipath signals cancelling each other and shading from almost any solid objects – even plastic. And it wont go through walls or solid obstacles at all well. And it’s way overused by everything! The fact that it works as well as it does is already a miracle and a triumph of engineering over practicality.
There’s 8 different sources of 2.4ghz in my room here alone. NOT COUNTING RC equipment! (now take a look at the photos above and all the houses there!)
Even my 3 chargers are using it to talk to the PC. And my phone, laptop, lighting system, keyboard and mouse, even my camera phones home! Smart utility meters are being installed everywhere right now, and so on. And more in my car. Even microwave ovens alone chuck out more power as leakage than your RC transmitters do intentionally! Fortunately mostly indoors – but all this escapes through flat roofs, windows etc.
For true long range for say 8 or 10 miles or greater (for FPV?), or control behind objects/walls/bridges etc look at the other lower frequency ‘really’ long range systems. 2.4 simply isn’t suitable. The higher the frequency, the more like a light bulb the signal behaves. The lower the frequency the more like sound the signal becomes. And then it goes through walls and around corners and bounces off things.
However, this booster really does make our cheap common existing 2.4ghz RC systems WAY, WAY better!
Even through walls and trees/cars – see the video links. And so SAFER. This booster does not appear to cause any other RC users any trouble at all. After lots of (amateur) testing at my club and at home it seems other systems are unaffected by it as far as we can tell. Proper safe control of that fast jet, or large model at a distance, high altitude glider is a huge plus! If concerned about overpowering other users, just stay a few paces away from other transmitters and models! Seriously its not an issue. And it will go through 4x more brick, trees, people, than without a booster.
2000mW boosted 2.4ghz, even allows for pretty good longish range FPV flights up to a very reliable 3 or 4+ miles with stock RC TX antennas. I will leave the politics of all of this to someone else! Ask someone if they want to REDUCE their transmitter power output, and see what the answer is! Obviously more output power is better/safer.
The booster needs an RF signal IN. This is just re-routed from where your original antenna was connected. Via a cheap eBay cable. This is plug and play stuff! And a boosted RF signal needs a path out of the other end of the booster, to go into the existing antenna! The antenna that you already have is as close to an omni directional antenna as you can get. So it the best one for RC use. No dead areas.
Booster also needs a 7v to 12v power supply. This booster is a Sunhans 2000mW 33dB Wi-Fi booster. These are very cheap on eBay. And better than the alternative ones that you may see, for our RC purposes, for a bunch of reasons.
Its the smallest of all the simple Wi-Fi boosters, but heavy. Offers better reliability than the bigger ones, and on DSMX runs cool compared to some, and only slightly hotter on DSM2. Why there’s a difference I have no clue! And it can run directly from a typical transmitter 9.6V or 12V battery pack direct. No need for voltage regulators to fail or complicate things. Plug and play power that comes from your TX directly.
I use a 3 cell LiPo in my transmitter. The Sunhans is connected to the POWER by simply soldering its two wires directly to the stock TX module/deck board. (pic Later!) So it comes on with the transmitters switch.
These boosters are available in black too, as 34db or 2500mW (2.5W) versions. The range difference 1dB makes though, is tiny & completely insignificant here, so either one is fine and will work equally well.
Note that there are two RF cables. into, and out of the booster. The connector that USED to go to the antenna on the stock TX module/board now gets re-routed inside the case to an adapter that feeds the boosters input. It makes its way via an essential ATTENUATOR (more later) to the boosters input. It exits the case through a tiny 2mm notch filed in the transmitters antenna housing at the top. See pics. Every transmitter model is different, think before you cut/drill/etc. Do it neatly!
The other wire exits the boosters OUTPUT, and enters the TX case the same way as the other wire came out. On the opposite side. It goes to a simple reverse U.FL adapter that connects to the stock transmitter antenna. Why? Because its already there, has the perfect radiation pattern for model flying, and its neater and looks tidy! Why use the higher gain (less even radiation) extra one that came with it? They are badly made too, so throw it away.
The ACTUAL SMA, U.FL etc connectors, adapters, you will need to connect the booster/attenuator/antenna you use and their lengths depend how you choose to install things and are not critical. There are links for these at the end of the page.
The VALUE of the attenuator you will need, also depends on the booster you buy (see its specs) and the transmitter RF output you have. Again I will tell you how to figure this out easily LATER!
BY FAR the weakest thing on this beautifully made transmitter, is the damned Nickel metal Hydride battery. Lipos. or LiFe is the way to go as it charges fast, STAYS charged until you want to go and fly, and has greater capacity than the stock battery. So…
This is not DIRECTLY related, but transmitter LiPo’s are now common. The 12x has a warning about their use cooking a voltage regulator. Its possible. So I added 2x plain 3 Amp power Diodes in series with the positive battery connection. Each diode has a 0.7v volt drop as most diodes do, so this LiPo battery when fully charged is dropped from its 12.6v to 11.2 volts. Its safer!
This TX + booster takes about 330mA boosting DSM2 and about 210mA when using DSMX and stays cooler. It turns on automatically with the transmitter. Battery time on this TX is therefore about halved! I get about 5 hours flying time. You may want a spare battery if this is inadequate. Its good enough for me. Especially as I can charge it fast at the field if needed.
Interestingly, power consumption, and measured average output signal strength, as well as (booster temperature) increase on DSM2, compared to DSMX very markedly.
And there is much LESS HEAT and less power consumption, and less measured signal strength, with less channels used. 12 channels, (or un-bound to a rx) makes masses of heat. 4 channels, stays very cool after bind. Especially in DSMX mode. RANGE in every case is the same and around 4.5 times better than stock.
A 4mm hole is drilled in the plastic TX module cover for the BOOSTERS power wire. Covers are cheap… Magnesium backs are not.
Booster lights are Green = Power. Blue = Transmit.
On DSM2 blue comes on bright, then flashes fast as it listens for a clean channel or two, then comes on solid but slightly dimmer. At least it does if its BOUND to a RX. If not it just comes on and waits. With DSMX it comes on 2 seconds after power up. No flash/flicker. As its not listening for a free channel.
Note grooves for co-axial cable are filed into top plastic antenna cover. This and the rear plastic module cover plate are the only plastic parts on this transmitter. 3mm needle file used. Only modify the cheap plastic bits! The rest of this back is magnesium, rubber and all bolts are polished stainless steel cap screws. At least they are now! 🙂 And expensive.
Booster is attached with simple automotive double sided trim adhesive tape. Strong stuff. Its solid. The bolt hole mountings are cut and filed OFF the booster. They look bad otherwise.
DIY UPGRADE YOUR EU/UK DSM2 JR 12X TRANSMITTER TO DSMX!
You can have DSMX frequency hopping safety on your UK 12x transmitter + use all the the Spectrum or JR DSM2 or DSMX receivers you already have. No need to buy that new fangled nasty cheap feeling plastic JR 11 channel DMSS transmitter and its expensive receivers.
This picture above, is the DSM2 internal transmitter board. It lives behind that plastic lid. That just pulls off. Use a credit card on the bottom corners! This is a dedicated 2.4ghz transmitter.
The MODULE version of the 12X sold in the UK and in the USA can use the slightly higher power USA transmitter modules. These are 200mW instead of 100mW and are a straight fit on MODULE versions. Inside the MODULE itself, the board is absolutely identical to the internally installed one in the NON DSMX 2.4ghz UK transmitter. NO firmware changes needed or anything else is required. Just swap the boards. This is literally a 2 minute job, and will only need your models re-binding to get DSMX. The TX may still ‘say’ DSM2 on the screen, but its really not!
The MODULES with DSMX are available in the US from any model shop as well as DSM2 and 35, 72MHZ modules. The DSMX module has a board that fits straight into the DSM2 UK transmitter. It fits and works and is tested. Its not technically EU compliant as it has double the output power, a 3dB gain over the UK/EU DSM2 one.
SO just buy a US module online, (eBay) dismantle it. The board shown above is inside it, looks identical, and fits straight into the UK 12x 2.4ghz transmitter but gives you more power and frequency hopping DSMX. Its simple plug and play that any retard can do, and you get DSMX and 1.3x extra range to boot!
DSMX alone will not give you a huge gain in range or performance, but if you fly in BUSY 2.4GHZ areas like in or near a town, it can help! It will not increase range in a noise free area, but the 3db power gain you also get with the US specs TX will slightly improve range. But if you want a real improvement you need the booster too!
Added. The 11 channel DMSS MODULE also has a similar looking board, and so if you prefer to change to DMSS this module can be cannibalised and fitted in place of the DSM2 board in the 12x too. (I am 95 percent sure this will work.)
BOOSTER IMPORTANT STUFF!
Note (picture above) that I soldered the power wires for the booster direct to the board. There are 5 unused holes on this transmitter board.
From the bottom up:
2 NEGATIVE BATTERY 0V
3 POSITIVE BATTERY VOLTAGE This turns on/off with the transmitter switch. Yours will be similar. If not, connect directly to your transmitters power switch.
And now look on the module/chip or transmitter casing, and there will be one of two things.
If you are lucky it will have a dB rating. That is it will say “21.1 dB” or similar. If not, then there will be a FCC ID number. Google it. This will tell you the accurate dB output. You NEED to know this. It tells you which ATTENUATOR to order.
Because to get full power from the booster, you have to feed it the correct ‘level’ of signal. Because its a linear booster. The Sunhans booster says MAX 17dB input in its specs. Some say 19dB. More than specified level causes signal distortion and possible failure of booster in flight and a higher output, Less means less output power than you could have had. Remember 3dB is half or double so get this right!
It works like this. Db’s are easy. They can be converted directly to watts or Mw if you want but there’s no need. The SunHans booster really wants 17dB at its INPUT. My transmitter is 21.1dB OUTPUT. (+2dB antenna gain = 23dB total or 200mW) To reduce that output to the 17dB the Sunhans wants, I simply ordered a 4dB attenuator from eBay. Why? 21dB less 4dB = 17dB! Its really that easy.
REMEMBER this does not do any auto signal level stuff. Its a linear power amp. If you feed it 17dB (or 50mW) it will give its full 2w output. That’s safe and reliable all day long.
Feed it with 3dB less, and you will LOSE 3dB on its amplification. So now you get exactly 1W or 31dB out. If you feed it 20dB on its input, you will get 3 Watts out or 36dB. Lots of signal distortion, and it will likely fail sooner or later. So try and get this correct!
Here’s some arbitrary but interesting figures that seem to wildly confuse the u-tubers / internet!
In EU or UK we have a MAX RADIATED power of 100mW. That’s 80mW (19dB) transmitter power and 2.32dB antenna gain so 21dB MAX
In the US and other places, that’s 200mW RADIATED. Or 128mW and 21.1db plus 2.32dB antenna gain. 23 TOTAL MAX
It can be less. Some are. So LOOK at yours!!!
Does it work? You bet it does!
I get about 3x the range through walls and houses. I get at LEAST 4x the range before failsafe cuts in on my FPV TBS Discovery quad-copter, and I can fly my glider quite literally several miles high via FPV safely.
From my wheelchair with single antenna RX, stuck on to the control pod, testing through a street full of walls and Wi-Fi to be as bad a test as possible.
REAL RF total power output using this booster is 3.2W! Or 32x more RF power.
Because, you have 33dB booster + 2.23dB stock antenna gain = 35.23dB total RF output (3.2+ watts radiated).
FINALLY – HOW NOT TO DO IT
And to be cautious watching U-tube experts. This will work. But for how long? Till he forgets to plug in the booster? Or till it burns out with no attenuator? Or until the cheap voltage regulator fails? Or a TX cable comes loose or is snagged?
No attenuator, maybe its not required here, but I don’t think he even considers it, wires and antennas sticking out all over and looking untidy, separate switches or BEC’s to power the booster, so you can forget to power it up and crash, or damage your RC transmitter etc.
The booster MUST be on when you power the transmitter. And the whole thing looking like scrap-yard challenge and just waiting to all get caught up and cables ripped out or damaged.
No doubt it works, at the moment, but in addition those particular boosters are not very reliable – many reports of failures on the web. Normally caused by too high input level – no attenuator…
I am not picking on this guy, in particular as I don’t know him, but this is common on many such ‘guides’ on how its done. There are many similar sites and u-tube guides. It may well work, but neat, well engineered and reliable it will not be. So that heavy large scale plane could go anywhere!
Just an example of what I was trying to avoid.