karla

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Next can fix OPlink trouble on the revo side?
« on: November 11, 2017, 11:15:19 am »
Hi,
One of my Revo boards have very poor range when connecting to my OPlink controller on the ground station.
If moving the TX to the next room, then the revo will failsafe. For my other Revo's that does not even impact rssi. The problem has to be on the aircraft side since when I am using other some 3 Revo boards with same antenna and everything, its just good steady long reach.



Now, I just want to explore if the Next build I have installed offer some new options to fix this over the current LP ver 16.09.
So far I have checked the Revo board so there is no short in the antenna socket with a continuity voltmeter,  but that's all the hardware check I made.

This is picking up from this thread in the past
https://forum.librepilot.org/index.php?topic=312.0

I have played around on the settings on the Revo side (should I try the OPLM side?) with the Xtal Capacitor settings ( ???) but the default setting of 127, seems still get the best signal strength.

Any software setting I can try?
Else What can I look for on the Revo board to spot faults?
I don't think I have the skills to de-solder the rf board on the revo and solder a new one on there - even though I have some 3 of them at home.
Can I change the frequency? are the other bands like 800 and 900 really supported by revo and oplink?


f5soh

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Re: Next can fix OPlink trouble on the revo side?
« Reply #1 on: November 11, 2017, 11:34:44 am »
If the link disconnect where similar hardware works fine at same place seems there is nothing you can fix using software in your case.
Anyways your link will work much better setting the Air data rate to 100000.

Xtal Capacitor settings simply tune one side with other and allow a fix for some Chinese hardware.
This do not improve the signal level but made better the reconnect if you loose the connection while far away.

Others frequencies are supported but need different/matching RFM22 module.

Compare the received signal strength using one Revo and others at same place without moving the OPlink "ground'
Swap antenna in Revo side and maybe found the culprit.

karla

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Re: Next can fix OPlink trouble on the revo side?
« Reply #2 on: November 12, 2017, 02:57:53 am »
Got it. thanks.

karla

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Re: Next can fix OPlink trouble on the revo side?
« Reply #3 on: November 14, 2017, 04:07:05 am »
Anyways your link will work much better setting the Air data rate to 100000.

Hm... I tried to change the air data setting on the Revo to 10000 but then it lost the connection to the OPlink mini on the ground side. It did not matter if I changed the setting on OPlink to 10000 as well - no signal, no connection.
Maybe just this Revo unit is a bad example.

Re: Next can fix OPlink trouble on the revo side?
« Reply #4 on: November 14, 2017, 05:15:44 am »
Count the zeros.  :)

You need 100000 (more than 56k or 64k) as opposed to 10000 (not enough for even stock telemetry).

Edit: well there isn't a setting for 10000 so you probably did use 100000.  Of course you need to use firmware made from same version of source code on both sides (OpLink and Revo) and set up both sides "from scratch" too.

If you don't need the tuning feature of next, but you do need higher data rate for some reason, then just setting old version firmwares to 115200 on both sides would do it.  I use 57600 (56k) for my 16.09 setups and have keep my telemetry needs low enough to not need a faster link.
« Last Edit: November 14, 2017, 05:27:46 am by TheOtherCliff »

f5soh

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Re: Next can fix OPlink trouble on the revo side?
« Reply #5 on: November 14, 2017, 10:05:44 am »
Your issue is certainly related to a config issue if was working using 64000 previously.

The "Air Data Rate" setting in Next is related to real baudrate used for RF link.
In 16.09 this setting was related to the effective baudrate assuming the link is not full duplex (when one side transmit, the other side is receiving only).

Comparison between previous setting and new setting in Next:
 16.09        Next (Air Data Rate)
19200    = 32000
38400    = 64000
57600    = 100000
                    128000
115200  = 192000
                     256000

So setting 100000 or 128000 will be fine for next and same as 57600 in 16.09

karla

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Re: Next can fix OPlink trouble on the revo side?
« Reply #6 on: February 09, 2018, 06:06:07 am »
All works well now, Air data setting rate at 100K  - thanks a lot.