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Mar 27, 2014, 01:47 PM
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Hubsan X4 H107D FPV Antenna & TX Battery Mods


Hello All! I have set off on a mission to accomplish two goals. I am sure that these issues may have already been addressed here on RCG, but the threads seemed to have disappeared among all the other threads.

The first challenge is to substantially increase the the range and signal integrity of both the control function and the video/FPV function. The one hitch here, is to do this with entry level skills and tools...nothing requiring oscilloscopes and other fancy RF tools! I want to keep the project reasonably easy and inexpensive.

The second challenge is to increase the amount of transmitter usage between battery charges/replacement. I plan on going from the factory design of four AA batteries over to a LiFe4 or LiPo battery.

Everyone, please share your ideas and questions

*Please note, this is an educational and entertaining thread. Please keep all posts on topic and of a positive nature. I will attempt to keep all the fresh modification ideas updated to the second post of this thread for quick and easy reference.

Below are some pictures of what the inside looks like and what we are up against. At initial glance, the challenges appear to be relatively simple to achieve...of course, time will tell!

Jon
Last edited by superjon; Mar 27, 2014 at 02:42 PM.
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Mar 27, 2014, 01:48 PM
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(this post will be reserved for quick-reference links of the project)
Mar 27, 2014, 02:03 PM
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My first concern is this(...take a look at the first photo below). Obviously, the antenna on the right (see the blue arrow on the right of the first pic) is the 5.8ghz antenna as it is clearly marked as such. It is my understanding that the transmitter/controller transmits on 2.4ghz. If that is in fact true, is the antenna "etched" into the surface of the circuit board on the left (see the blue arrow on the left of the first pic) the actual antenna used to transmit the control RF? My concern is that what looks like a small antenna may in fact not be the antenna. Perhaps both the "transmitter" and the quadcopter are equipped with a transceiver capability and everything is fed through the 5.8ghz feed.

What do you all think?

In the second picture you can see two "knock-outs" that are at the top of the transmitter case. I plan on drilling them out, mounting two SMA connectors, and then soldering a piece of antenna cable from the SMA connectors to the respective locations on the circuit board. Then, put a 2.4ghz "rubber ducky" or unidirectional higher gain antenna on the one SMA connector and put a 5.8ghz Clover leaf or unidirectional high gain antenna on the other SMA connector. Hopefully, the antennas I use will have the ability to be rotated while installed making for safe and easy storage of the antennas when the transmitter is transported and not in use.

Jon
Mar 27, 2014, 02:17 PM
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One of my biggest complaints with this transmitter design is with its power consumption. Even with rechargeable Lithium Ion AA batteries, I find I am constantly having the transmitter need the batteries replaced/recharged. this is annoying.

As well, I never can seem to get the Tx battery strength indicator on the display to show 100%. I am not sure what that is all about?!

So, while I had the transmitter apart to work on the antennas, I scoped out the battery tray design. Oddly enough, the manufacturer put a removable battery tray into the two major case halves. The tray simply snaps out of the front case half. The wires had to be soldered to be removed. You can see the tray removed in the picture below.

What I plan to do is get a LIFe4 or LiPo 2s pack that fits in that bay. Then, I will put a red JST connector in place so that the battery can be easily disconnected for servicing. The battery tray that was removed measured approximately:

4.250" (L) x 1.250" (W) x 0.8125" (H) (108mm x 32mm x 21mm)

One major downfall of installing a battery that will use most of this space is that the complete back transmitter case half will have to be removed (4 screws...very easy) to install and removed the battery. The battery that is that big will not fit out through the OEM battery cover. Ultimately, this is not such a big deal because I rarely ever remove the battery pack on my major transmitters if I can charge them while they stay in the transmitter!

Once the battery is installed, I will feed the battery output into a small 6 volt BEC to ensure proper and steady power feed to the circuit board.

Do you all feel that the electronics would be safe if the input voltage was 6.5 volts? Perhaps this would clear up the TX voltage indicator issue on the display as well as slightly increase the RF output. As well, I would then run a 3s battery pack and modify a BEC to output a tru 6.5 volts.

Jon
Last edited by superjon; Mar 27, 2014 at 02:55 PM.
Mar 27, 2014, 06:18 PM
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Similar to the Devo F4, if the 5.8g vrx antenna is IPX simply get an IPX to sma adapter, about 6--8" and run it up to the top to connect to a nice panel antenna, works great. I believe there are some threads on replacing the antenna which I will try to locate .
Mar 27, 2014, 07:20 PM
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Quote:
Originally Posted by Waterbound
Similar to the Devo F4, if the 5.8g vrx antenna is IPX simply get an IPX to sma adapter, about 6--8" and run it up to the top to connect to a nice panel antenna, works great. I believe there are some threads on replacing the antenna which I will try to locate .
Unfortunately, none of the antennas are IPX. The antenna coax is split and then soldered directly to the RF Modulator.

But I am curious. Is the small trace on the circuit board that I have the arrow pointing towards the antenna for 2.4ghz? The length is about right to be a 2.4 antenna...

Jon
Mar 29, 2014, 02:02 PM
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Well, today I decided to disassemble the quadcopter as well to determine what practical options are available to modify the antenna(s) on it.

In doing so I am further confused. I thoroughly examined both circuit boards. The only antenna I can see is the obvious large one that is mounted horizontally to the bottom exterior of the case. As you can see in the pics, there is a small coil of copper wire around a ferrite core mounted on the one side of the black circuit board. I would assume that is not an antenna, but sort of coil for a transformer.

So, the great mystery continues! Do the controls, in fact, come to the quadcopter over the 5.8ghz band along with receiving the video feed and quad battery status on the 5.8ghz as well?

Jon
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Mar 29, 2014, 03:08 PM
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Check between the leds of receiver, if you look carefully you will find the same type of 2.4ghz trace antenna then the tx.
Mar 29, 2014, 06:58 PM
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Sweet! I'll look into it!
Mar 29, 2014, 07:27 PM
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new hubsan


Hey there was just wondering if you have had any progress on the antennas and battery upgrade.
just received my new h107d .
figured out 3.5mm out on controller can be hooked up to your tv by 3.5mm-rca
50" view screen is awesome lol just wish it was more portable
just ordered usb to rca to connect to pc while in flight hopefully it works.
Mar 29, 2014, 08:56 PM
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Quote:
Originally Posted by rugged1234
Hey there was just wondering if you have had any progress on the antennas and battery upgrade.

just received my new h107d .

figured out 3.5mm out on controller can be hooked up to your tv by 3.5mm-rca

50" view screen is awesome lol just wish it was more portable

just ordered usb to rca to connect to pc while in flight hopefully it works.

I'm still waiting for all my parts to arrive. I'm chomping at the bit planning my next moves!

I like the idea of hooking it up to the big display. I have a lens on the way to do the "Wide Angle D lens" mod. That will really make the big screen look great! I'm not covering that mod on this thread since it's been covered by so many others on here and YouTube.

The other major mod I'm hoping to find a solution for is to put on of the new micro GPS boards in this for simple GPS functions like altitude hold, loiter, and return to home. Of course, that would be covered in a new thread.

I'm in love with this little thing!
Mar 31, 2014, 09:00 PM
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yes I was to just did a night fly and it got away crap. any idea s on where to get just a replacement copter or the insides anyway have a crash kit on order and it comes with two motors and shell and feet and blades all I need realy is the main board and the camera I would guess. please let me know if you have a supplier. thanks

check out my first and only video on youtube under craig or rugged
Mar 31, 2014, 09:06 PM
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yes I was to just did a night fly and its gone. crap ...
well I have a crash kit on order and was wondering where I would get the internals or a replacement copter|? please let me know thanks

check out my only video I got on youtube under hubsan x4 h107d under rc fun
Apr 01, 2014, 07:54 PM
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Quote:
Originally Posted by rugged1234
yes I was to just did a night fly and its gone. crap ...
well I have a crash kit on order and was wondering where I would get the internals or a replacement copter|? please let me know thanks

check out my only video I got on youtube under hubsan x4 h107d under rc fun

BangGood.com has the boards and lots of parts. That's where I got my h107D from.
Apr 01, 2014, 09:04 PM
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hopefully you are able to figure out a gps unit. let me know thanks would have been great to have it on unit b4 I crashed lol


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