Removing shield and diode 7E for better reach

200QX: Some have problems with the wrong antenna length!!
www.helifreak.com/showthread.php?t=688336

For proper range testing I highly recommend Spektrum AR6210 (including SAT) + TM1000 with enabled telemetry FlightLog monitor.

I've noticed 25mm antennas on a few chinese receivers for various things.. I think someone got wrong info at some point and everyone now uses it.

It is clearly stated by HH support that the antenna must not be 25mm but 31,25mm (30-31mm).
Different HF members confirmed that for the 200QX antenna that this is not always the case. Was not for me either.

So it makes no sense to complain about bad signal when the 200QX antenna even does not have the right size lambda 1/4.

Guys, get a real good Spektrum receivers with telemetry (TM) and do your tests with that

I received a new 7E today, flashed with latest nightly.
After reading this thread I decided to do a quick test before doing the diode mod.
I enabled the PA in the hardware.ini file.
I then varied the power output settings and it definitely makes a difference.
Using an OrangeRX R615X receiver:
At the lowest setting the transmitter had to be within a couple of feet of the receiver.
At the highest setting I walked out ~500 feet and still had a link but the LED wasn't solid.
Is this the same results that is seen after the diode mod?
Does this mean the PA is enabled from the factory and the diode mod is no longer required?

It simply means that the Deviation firmware correctly sets power levels in the main chip. The diode disables the power amplifier (PA), and by shorting the diode you enable (in hardware) the PA. Shorting the diode should increase your Tx power significantly.

As a counterproof, try disabling the PA in your INI file, and repeat the test. With the original 7E, you should see no difference between having the PA enabled in INI or not. 500 ft is what an un-modified 7E can do, a modified 7E can do 5000 ft (line of sight). Enabling the PA in the INI file, without the diode mode, makes no difference

Arakon wrote: I've noticed 25mm antennas on a few chinese receivers for various things.. I think someone got wrong info at some point and everyone now uses it.

Yes, you are right, even on my S603 the antenna was 26mm. Therefore I had to removed a part of the shielding to adjust the length for a quarter wavelenght.

robca wrote: It simply means that the Deviation firmware correctly sets power levels in the main chip. The diode disables the power amplifier (PA), and by shorting the diode you enable (in hardware) the PA. Shorting the diode should increase your Tx power significantly.

As a counterproof, try disabling the PA in your INI file, and repeat the test. With the original 7E, you should see no difference between having the PA enabled in INI or not. 500 ft is what an un-modified 7E can do, a modified 7E can do 5000 ft (line of sight). Enabling the PA in the INI file, without the diode mode, makes no difference

OK - I understand - thanks.
I'll crack it open as soon as I can.

Jerm357 wrote: Ok, cool. Just to make sure, heres a video of what mines doing at full power. Does your voltage do the same?

I spent hours and probably damaged my controller board some trying to fix this voltage fluctuation... is this really normal for just doing the range mod?

This seems odd because if I change protocals it will stop doing this. Even if I switch back to the original protocol (oe I use DSMX so I can switch to DSM2 then back and now voltage is stable however doesn't connect to quad)

aMax wrote: ...yellow = new bridge
...blue = measured points = 0 ohms

Attachment not found

I am curios about this because due to damaging the trace protectant under where the diode used to be I cannot use a wire to jump the pads due to risk of shorting the trace.

So I am jumping basically exactly the yellow line n this picture (ie my wire goes from the top of the bottom diode to the left leg of the top one)
I am not convinced it's working right as I only get 200 metes or so of range but I am wondering:

1: Is what I did theoretically sound? id if you can't bridge the original diode mount points, can you just bridge the yellow line and get the same result?

2: How does the diode work if it's in line with other diodes? Does the bard read certain resistance and turn off the PA? Because I would think if it was just a matter of reading any resistance then the remaining diode in line would still provide that.

3: Which is leg 5 of the T212? Because if the through hole (basically where the red letter B is in the picture above) really does go to what I think is pin 5, then it also shorts directly to the left pad of the thing marked A as leg 5 seems to be connected by trace to a through hole and the left side of A... I want o test my connections but need to mak sure I am testing the right things....

Thanks!

This was only work around, ...pads came off.
...don't refer to this.

aMax wrote:

Arakon wrote: I've noticed 25mm antennas on a few chinese receivers for various things.. I think someone got wrong info at some point and everyone now uses it.

Yes, you are right, even on my S603 the antenna was 26mm. Therefore I had to removed a part of the shielding to adjust the length for a quarter wavelenght.

.... and I was wrong with this. Finally I had to cut the activ part down again,.... to nearly 27mm, because of the velocity factor at my coax.
en.wikipedia.org/wiki/Velocity_factor
www.rcgroups.com/forums/showthread.php?t=2371720

My situation requires a workaround because I exposed the traces under the diode so bridging it now has a huge chance of shorting it against the exposed trace.

I am pretty sure I did that the other night resulting in a 1 meter range.

So for now while I prefer not to do it that way, I just need to confirm it should indeed work? Based on checking resistance everywhere I can think to it seems it should as I get no resistance between the solder pads and their adjoining chips along the same trace...

I have a conductive pen coming in the mail, I will probably try o repair the damaged trace and bridge the original pads in a slight detour but that won't be easy so just trying to verify all my options before I screw up even more

It would have been more useful you had posted a photo of your module....
Here is a picture of how the pactl traces( yellow) run. The red arrows could be your bridge to get around your problem
If you need more space, you can even use the via below as one solder point, but be very careful !!

Sorry here's the best picture I could get.

Good thing I did take the pic because it isn't exactly what I remember doing (at 5:30 am on a very stressed out night).

Ignore the small flyaway wire at the top, it is above everything, doesn't contact anything and I have measured resistance against it. It is also covered by electrical tape when it's all put back together so it's not shorting to the shield either.

Your picture is clearer so what I did is draw some purple lines to show where I tested resistance to make sure they are not shorted. Both purple lines represent resistance of 1.

Where your red arrow is I show near zero resistance which is in line with the resistance I get when touching the probes together directly.
So I think all should be good... but my range maxes out at 1000 feet and in real life conditions is only reliable up to about 200 meters before there is significant chance of dropouts.

This is with PA enabled in hardware and power pushed to 150mw.

In Devioation 4.01 I can hear the speaker interference ramp up at each step in power including 100-150mw but I am not sure that means the PAi is actually working.

My voltage meter also constantly jumps around by sever hundreths of a volt all the time.

Thanks for any input!

MicSmitty wrote: Welp, wish I didn't attempt to do this mod with a regular soldering iron either as I also failed So I purchased a 8s module and it's on the way. However I have some questions:

Since the 8s module sits ontop of the 7e's PCB and the pinouts don't line up perfectly, how do you install it? Use wires and secure 8s module somewhere else?

To help others in installing a 8s module in a 7e transmitter (and so others understand what I'm asking) below in the attachment pic is the pinout I found in another thread by PB. I just wrote it differently to show how you can't place the 8s module directly on the 7e PCB like it was...

Also, what happens to the 8s module pinouts 7,8, and 9? Don't use them?

Again, thanks to all for this project/forum/user materials.

In the above under the 7e Pin Point, Point 3 is MOSI and Point 4 is MISO, but go to bitbucket.org/PhracturedBlue/deviation/wiki/Devo7eModuleInstall the points are other way around.

I am a new to all this, I might be wrong. I just want to know which is correct or my eyes are playing tricks with me .

By the way. I heard this mix-up to often now. The 0603 chip that is removed as part of the mod is actually not a diode but a 10k resistor. I did not invest enough time to figure out which exact PA and schematic they are using there but this is quit possibly a input to the PA.

aMax wrote: Please check blue first.... just to know, if there was a short or not.

Yellow is the allowed bridge...., but if you are able, take the bottom pad of the removed diode.

Edit: You only will find one connection with 0 Ohms, I don´t know to which pad the trace goes, but I think to the left.

Added a picture of the PACTL lines.

Hi. Can I please get some help with this? I tried the diode mod and torn the upper solder pad off. I found this in an earlier post, but I don't quite understand where to install the new bridge. Is it where the red arrow is or do I run wires the same as the yellow lines? See attached picture

Hi,

what is the best way to check if the mod was succesful, considering I didn't do a range test before the mod, nor current measurement.
What is average range on the lowest setting with and without the mod? Or maybe there is a better way to make sure the mod was succesful?

The component being removed for this mod is NOT a diode.
It is however a 10k Ohm resistor.



The photo above is with the component removed from circuit and being measured while resting on the larger component.
Note, I reinstalled the resistor and simply solder bridged over the top of it so that I can reverse the mod if later desired.

noob disclaimer: My fingers are crossed for the images to upload -

Tonight, I used a Spectrum Analyzer to help validate the differences in output power when changed via software settings under
--> Model menu --> Model setup --> Tx power

100uW


300uW


1mW


3mW


10mW


30mW


100mW


150mW[/b]


Scan Settings:
Start: 2401.000MHz
Stop: 2416.234
Step Size: 25.391KHz
Sweep: 1.71 Sec.
Res BW: 58.036 KHz

Setup: Unit Under Test #1 (Modded Devo 7E) was 2ft from Analyzer's Rx Antenna

Note, I did not test before performing the hardware mod by bypassing the 10k Ohm resistor (more commonly being referred to as diode) followed by editing the hardware.ini file within the root folder. However, I plan to measure a stock Devo 7E before mods are performed under similar test conditions.

I also plan to perform similar testing at distance in open field as time permits.