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Dual Module Range Issues - OrangeRX and Turnigy 9X Stock

Snarls

Gravity Tester
Mentor
#1
Hey guys if you remember last month I modded my Turnigy 9x to have both the external stock module and an internal OrangeRX DIY module. This issue now is that I am getting very poor range on both modules. With the stock I get around 80m through trees and with the OrangeRX I get around 60m through trees and max 300m in an empty field.

After research I think I can conclude that it is not the TX itself that is the problem, it is the modules because all the TX does is provide power and signal to the modules which is obviously happening. If I'm correct it is the modules job to provide the range. So what I'm thinking is that I may have messed up the antenna on my stock module by trimming the coax a little where it connects to the board. For the OrangeRX I'm not sure if the antenna I got is bad, or if the module itself is bad. No way to tell except to buy a new antenna.

I'm thinking of getting this one from Amazon along with this pigtail. Can someone confirm that will work, it looks the same as what comes with the DIY module. If you guys have any other ideas of what could be wrong please let me know. I can still fly proximity FPV, but I'm dying to get out and explore the area around me without worry of loosing signal. Thanks!
 

HawkMan

Senior Member
#2
you have it set up so only one module is active at a time ? otherwise they might interfere with each other.

and those internal wires can be somewhat sensitive, but as long as you didn't strip of the shielding from any exposed wire inside and didn't put any sharp bends on it, it should "probably" be ok. But without equipment to measure it it's hard to tell.
 

Snarls

Gravity Tester
Mentor
#3
Yes only one module gets power at a time. I even removed the external stock module and the range of the internal OrangeRX did not improve. No sharp bends and the OrangeRX did not involve any soldering for the antenna, only for attaching pos, ground and pwm. I may try re-soldering the antenna in the 9X stock module.
 
#4
Check your antenna, I had an issue like that because the external antenna was rpsma when the module was sma. It might just be the antenna's connection to the module not being completely connected
 

pressalltheknobs

Posted a thousand or more times
#5
You are correct. The modules do all the actual transmitting and they and their respective antennas determine the range.

The rest of the gubbins in the box is there to control what information gets transmitted.

That said, the effective range will be affected if the signal you give to the tx to transmit is not good or the power is not solid. Bad connections seem like a probably cause particularly since you are getting the problem with both transmitter modules

Since the Orange is essentially self contained and just powered from the controller most likely there is a bad connection somewhere where you connected it. It seems likely you have a dry solder joint somewhere. so I would check your solder joints and make sure they are good. If you have a multi-meter (and you really should if you are doing projects like this since they are very inexpensive these days), then with the power off you can use the ohm meter to measure the resistance of you joints. Its not totally fool proof but it it will measure a resistance in many case showing that the solder joint is not good. With the power on you can measure the voltage across you solder joint and see if there is any drop on the +ve side or of the-ve side is not solid. You can also measure the voltage across the -ve and +ve and make sure it is a solid voltage (probably around 5v I suspect.

Presumably you soldered +ve -ve and pwm and you have a switch that disconnects one module and connects it to the other? If so it could be the switch. A test would be to by pass it and make as direct connection as possible for all three signals.

If the pwm line is long there is a possibility it is is getting attenuated or there is interference that is affecting the signal. This seems unlikely though unless one of other of the power connections are bad.

Another possibility is that you somehow damaged the components in pwm output stage bu overheating them or possibly accidentally de-soldering a surface mount component. If its none of the above I would check around for this. Follow the traces and make sure there is not signs of overheating
 
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Snarls

Gravity Tester
Mentor
#6
Thanks Spastickitten, I have made sure the antennas and connectors are all matched correctly.

Thanks pressaltheknobs, I have checked my soldering multiple times and I do not detect any cold joints. I'll have to try measuring voltages, but I do not think cold solder joints are an issue. I do use a switch, but I have already tried bypassing it with no change in range. The board in the back of the 9X where all the soldering is done is all traces, there are no surface mount components to mess with. I do know that when I soldered on one trace, some solder flowed under the top layer and bubbled up a little bit. That said, the connection seems fine.

What I would like to ask is for anyone that has a 9X to measure these resistances for me: The resistance between two adjacent pins starting from the left on the row of pins on the image I've attached. So if the pin on the left is pin 1 and right 12, measure the resistance between pin 1 and 2, 2 and 3, 3 and 4 and so on, and make sure your ohmmeter is in the thousands. Thanks.

internal moduleh.jpg
Note this image is old and I have since cleaned up the soldering considerably.
 

Snarls

Gravity Tester
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#8
I'm using a full range LemonRX DSM2 Sat receiver. I thought about if the problem was DSM2, but this is a constant issue and not an occasional signal loss.
 

pressalltheknobs

Posted a thousand or more times
#9
Well certainly seems like you should be getting more range. What range did you get with the stock receiver before the mod. Did you test it in the same location using the same method?
 

Snarls

Gravity Tester
Mentor
#10
I never did a full range test before the mod because the stock module does not support range testing and walking a mile or two away from the TX would've been tiresome. I did however try testing the range with the stock module and an RX that had its antenna chopped off. In a park I very roughly got around 150m with one building in the way. After the mod I did not fully test, but it seemed in the same field my plane would start acting strange around 50m out.
 

Snarls

Gravity Tester
Mentor
#11
Update: I got a new OrangeRX DIY module because the old module seemed to have a faulty antenna, but the problem remains. This is really frustrating me and honestly I may just get a Taranis when their in stock and save the 9x for small park flying.

I bypassed the back board entirely and tapped directly into the power and signal wires coming from the main board and there is no difference. At this point here are the possible problems: The ppm signal is off going into the module, the power to the module is not stable, both OrangeRX DIY modules are bad, or lastly that the LemonRX DSM2 Sat I'm using is bad. I will check the power to the module and order a DSMX LemonRX Sat, but I won't be able to test it for at least another month. Can anyone suggest something for checking/ changing the PPM signal going to the module from the main board? Does PPM frame and delay make a difference? It's all a mystery for me.