Removing shield and diode 7E for better reach

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01 Jun 2015 12:36 #33315 by mstrghettorigg
Replied by mstrghettorigg on topic Removing shield and diode 7E for better reach
Hi aMax,

Are you saying that I need to add a 12.2k ohm resistor at the missing area on my picture?

Please confirm.

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01 Jun 2015 12:54 - 01 Jun 2015 13:09 #33316 by aMax
No, the part I messured, is the removed part from my RF module, the one you have simply jumpered.
Test the part that is shown in the yellow quare on my picture and replace the same value for missing.
I messured these before mod but can't remenber the value.
Your jumpered part and the missing one are inline. What the throughhole to the backside does....., can't remember.
Look at the blue line, I think, that is the trace you need to have.

Devo7e, TaranisQ X7, R9M , 4in1 MM, Futaba FC18plusV3.2 & DFT/FLD-02
Attachments:
Last edit: 01 Jun 2015 13:09 by aMax.

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01 Jun 2015 12:58 #33318 by PhracturedBlue
Replied by PhracturedBlue on topic Removing shield and diode 7E for better reach
I haven't opened up my 7e to check it, but with a multimeter you should be able to verify what aMax is saying.

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01 Jun 2015 13:28 - 01 Jun 2015 15:02 #33320 by aMax
But now there is the question, what does the resistor do which is still in the trace and where does the trace go which ends at the through-connection.
Is this mod completely done by removing or jumpering only one resistor?
Folks, we might have to messure the real output to be sure. Anyone with an antenna socket and access to a RF power meter out there...?

EDIT:
As far as I can see, this trace goes to pin5 (SWPA) at the T212 and the RF-in is connected to pin 2(RFin+ with pa bypass function).
So my clue, if there is no diode but a resistor, the PA may be already open and useable
EDIT2:
The control voltage is +4V and therefore a second resitor makes sence....(......as voltage divider ????)
With two R12K at 6V there is 3V out. Too low for the PA to switch.

Devo7e, TaranisQ X7, R9M , 4in1 MM, Futaba FC18plusV3.2 & DFT/FLD-02
Last edit: 01 Jun 2015 15:02 by aMax.

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01 Jun 2015 14:29 #33322 by mstrghettorigg
Replied by mstrghettorigg on topic Removing shield and diode 7E for better reach
Alright thanks guys. I didn't get a chance to measure the resistance before I left for work but I'm going to snag a 10k from here and hope that it's what I need. I'll let you guys know how it goes.

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01 Jun 2015 14:37 - 01 Jun 2015 14:37 #33323 by aMax
Mind my edit above.

Devo7e, TaranisQ X7, R9M , 4in1 MM, Futaba FC18plusV3.2 & DFT/FLD-02
Last edit: 01 Jun 2015 14:37 by aMax.

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01 Jun 2015 15:58 #33326 by PhracturedBlue
Replied by PhracturedBlue on topic Removing shield and diode 7E for better reach
there shouldn't be 4V anywhere on that board. I would expect either 3.3V or 5V, but not 4V.
The PA voltage threshold is 2.8V if I recall correctly.

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01 Jun 2015 16:19 #33328 by aMax
Yes, You are right.! This voltage was the max voltage for input, my fault...
PA on is from 2.8 to 3.0 V. ( RDAT212 data sheet)

Devo7e, TaranisQ X7, R9M , 4in1 MM, Futaba FC18plusV3.2 & DFT/FLD-02

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01 Jun 2015 18:07 #33329 by mstrghettorigg
Replied by mstrghettorigg on topic Removing shield and diode 7E for better reach
Well I guess I'm confused of why my unit didn't come with this resistor. Hopefully placing a new resistor will increase my range for me. I'm probably getting 50 yards or so using lemonRX. I read some people earlier having issues with this but sounds like they got it resolved.

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01 Jun 2015 20:51 #33335 by PhracturedBlue
Replied by PhracturedBlue on topic Removing shield and diode 7E for better reach
I don't recommend just randomly guessing what is wrong with your Tx. You could easily ruin it beyond repair if you connect the wires improperly. If you set the Tx power to 150mW what is your range? what was it before you did the hack?
We need to understand the circuit, and how it was changed in your Tx before we can tell you how to fix it.
Do you have access to a logic analyzer or scope?

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01 Jun 2015 21:09 #33336 by mstrghettorigg
Replied by mstrghettorigg on topic Removing shield and diode 7E for better reach
The range is about 50-60M or so. I'm terrible at guessing distance but it's not very far.

I do not have access to those tools.

i just don't know how I can figure out what needs to be done since I don't even have anything to compare it to. Well I do have another one in a box I plan on selling so I rather not open it.

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01 Jun 2015 21:24 #33337 by PhracturedBlue
Replied by PhracturedBlue on topic Removing shield and diode 7E for better reach
what was the range before you modified it?

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01 Jun 2015 21:34 #33339 by mstrghettorigg
Replied by mstrghettorigg on topic Removing shield and diode 7E for better reach
Oh sorry. I meant range is 50-60M before and after the mod.

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01 Jun 2015 21:37 #33340 by mstrghettorigg
Replied by mstrghettorigg on topic Removing shield and diode 7E for better reach
Based on image from aMax, the blue connection he mentioned is not connected on my board due to the lack of the resistor at least from what I can tell on the top side of the PCB. Maybe this is why before and after jumper is not effecting the range? I'm just guessing here since I don't know how all this is working.

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01 Jun 2015 23:11 #33343 by aMax
From where did you get this tx? The range is even without PA too small.
Before starting to mod anything, you should get the status of pin5 on the T212 at a low and high power setting.

Devo7e, TaranisQ X7, R9M , 4in1 MM, Futaba FC18plusV3.2 & DFT/FLD-02

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02 Jun 2015 00:29 #33345 by mstrghettorigg
Replied by mstrghettorigg on topic Removing shield and diode 7E for better reach
I order off of ebay. It looked like it was new in the box.

I did end up putting that resistor on and it looks like the range improved a bit. Maybe another 20M.

I tried putting it at the lowest setting and it only was like 5M or less.

So right now I feel like I'm at 80-90M range.

Could it be my LemonRX? I do feel like I was getting slightly better range with RX701, but I don't have it available to test it anymore.

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21 Jun 2015 11:29 #34439 by omri
mstrghettorigg,
I think I have a similar layout without the bottom element. I didn't change the software script but the fix does not work and it seems that the 7e does not function correctly. Can't get it to bind with a ladybird and the power off switch doesn't work, you can turn it on but not off.
Could you explain what you did to get it working?

Thanks

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22 Jun 2015 00:20 #34482 by mstrghettorigg
Replied by mstrghettorigg on topic Removing shield and diode 7E for better reach
Honestly I didn't get a solution. I put on the 10K resistor for that area and I think the range increased a little bit but didn't improve much. I gave up and bought a taranis.

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26 Jun 2015 21:08 - 26 Jun 2015 21:30 #34702 by raduque
Replied by raduque on topic Removing shield and diode 7E for better reach
Well, I tried doing this mod because I was only getting about 40 FEET (not meters, feet) of control range with a Blade 200QX. Unfortunately, it didn't seem to affect the range any. It's possible the mod didn't even work; I tried bridging the diode using solder but only succeeded in removing the diode. I then tried using a small piece of twisted-strand wire to bridge the pads, but I only succeeded in removing the diode immediately to the left of the one that needs to be bridged (assuming the top of the TX is facing away from you).

I finally got the wire to attach to the pads and I used a touch of hot glue to keep it from moving.

Two questions: Will the TX (or at least that radio module) be ruined by the missing diode? Second, is it possible that missing diode why the range mod doesn't seem to work (Could also be my crappy soldering though)?

Edit: It's the component circled in red in this picture:
lh4.googleusercontent.com/-t1-pIALQ0Fw/U...7E_TXModule_Zoom.jpg

Edit2: I guess the mod IS working, as when I go from 100uW to 150mW the battery voltage goes from 5.49 to 5.43. That's a difference of .06v. I don't know what the stock difference was though. I will test a little more when my 200qx's battery is done charging.
Last edit: 26 Jun 2015 21:30 by raduque.

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27 Jun 2015 03:29 #34724 by Daryoon
Replied by Daryoon on topic Removing shield and diode 7E for better reach
You can completely remove that diode/resistor and solder in a wire in it's place. 40ft even before the range mod is very little. But hopefully with the range mod, you can get beyond park range.

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