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General Category => General Discussion => Topic started by: kennyevo on April 11, 2016, 06:03:03 pm

Title: OPlink Vehicle control looses it
Post by: kennyevo on April 11, 2016, 06:03:03 pm
Hi!

I'm using oplink with ppm and telemetry at the same time, and sometimes it just looses control (like I don't give throttle).
Any idea?

P.S.:
I haven't tried with PPM only yet, will update the topic later.
Title: Re: OPlink Vehicle control looses it
Post by: f5soh on April 11, 2016, 06:07:55 pm
Whats the range ? 100m, 1km, 10km ? :)

I think its normal you loose the link at some point.
When link is lost board go into failsafe.
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on April 11, 2016, 08:33:31 pm
Hi!
It's about 5 or 10meters (that's why it's strange).
It starts freefalling for 2-5secs and then everything goes normal again.
Title: Re: OPlink Vehicle control looses it
Post by: f5soh on April 11, 2016, 08:51:49 pm

Connect the Revo to the computer and put your transmitter away, maybe 30m.
Go to Oplink tab and check what you get for bargraph (dbm level) and link quality
 
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on April 12, 2016, 05:28:45 pm
The bar goest to 1/3 if I bring the oplink and the revo about 30m away, it's quite low signal strength for 30m :/
And it jumps to 1/3 and 1/2.
Title: Re: OPlink Vehicle control looses it
Post by: f5soh on April 12, 2016, 05:39:35 pm
Do you see link quality changes ?

Double check antennas.
Assuming you set the same power in both sides and distance/position are the same:
- monitor the dbm value connecting Oplink to Gcs
- monitor the dbm value with  Revo to Gcs.

Compare. If asymmetric there is something wrong with one antenna or module.
Title: Re: OPlink Vehicle control looses it
Post by: nitromethane on April 12, 2016, 10:09:43 pm
I had my quad dropping at some point using OPLink for control and telemety.

Had to to reorient the antennas, and the problem went away.

In my experience it is best to have antennas oriented vertically and away from metal and carbon fiber parts, definitely don't run them parallel to conductive things like aluminium arms...
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on April 14, 2016, 10:03:07 am
So I think I've found the root of all evil. Maybe my oplink is faulty, because if I power it from the usb port it works perfectly, but with an external power supply (through main or flexi port) it disconnects in every 2 minutes :/ (even if it's a stable 5.3V from a power supply)
Title: Re: OPlink Vehicle control looses it
Post by: nitromethane on April 14, 2016, 01:09:16 pm
Maybe a faulty diode (D1 on the schematic, a small 3-pin device on the board) or a faulty solder joint on the main or flexi port JST-SH connector or crap wiring?

I'm assuming a glitchy external power supply is out of the question...?

If powering it from USB works flawlessly everything behind the D1 diode should be fine.
Title: Re: OPlink Vehicle control looses it
Post by: rmcferon on April 14, 2016, 02:30:26 pm
I gave up using my OPlink for control.

I had the same issues when using PPM + Telemetry and when using PPM only. I set my failsafe to RTB to save crashes.

When I watched RSSI on the OSD it would go from 100% to 0% and then after about 2 - 3 seconds back to 100%.

This was always at a range of <300m. I used two different ground units with the same result.

Very random and very annoying.
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on April 15, 2016, 06:40:23 pm
I was wrong, my oplink control looses connection on 30m, I have set it up with ppm only and 100 tx power on both side..
I'm using the antennas that was bunled with the fc. Both antennas are pointing up, is it possible that my oplink is dead? How can I test which side is dead?
Title: Re: OPlink Vehicle control looses it
Post by: f5soh on April 15, 2016, 07:00:35 pm
How can I test which side is dead?

Post #5 above
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on April 15, 2016, 07:48:13 pm
How can I test which side is dead?

Post #5 above

Ah really, thanks!
Title: Re: OPlink Vehicle control looses it
Post by: donnellb on April 16, 2016, 07:33:31 pm
Mine would disconnect and reconnect. What seemed to resolve the issue was to reduce the number of channels it could use. I'm in the US so I set it to 75 (top number) and 53 (bottom number) .

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Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on April 23, 2016, 03:45:05 pm
Okay, I think mine is broken, it looses signal after 12-30m even with ppm only and narrowing the channels :/
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on April 27, 2016, 07:51:32 pm
I get disconnection at 10m indoor,and less the 2m in the field. I had try different channels, different Power settings, my next test will be, to have a USB connected to the FC, and a USB connected to the Ground controller, two different laptops, and monitor the dB rates in both.
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on April 27, 2016, 09:07:56 pm
I get disconnection at 10m indoor,and less the 2m in the field. I had try different channels, different Power settings, my next test will be, to have a USB connected to the FC, and a USB connected to the Ground controller, two different laptops, and monitor the dB rates in both.

I'm curious about the result :)
Title: Re: OPlink Vehicle control looses it
Post by: f5soh on April 27, 2016, 09:19:03 pm
I'm curious about the result :)

That what i asked here: https://forum.librepilot.org/index.php?topic=1332.msg9734#msg9734
At least you can know the wrong device if the RF power is the issue.

From tests i did here i got around 100m where the link is completely lost, with minimal power (1.25mW)
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on April 27, 2016, 11:09:23 pm
I will post a video with both laptops conected

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Title: Re: OPlink Vehicle control looses it
Post by: finst on April 28, 2016, 12:07:21 pm
Did a quick test today:
Instead of moving the revo around, I  took my oplink for a walk after I started logging the revo. The log shows a signal strength of around -70db with a distance of about 50 meters between revo and oplink. Both devices connected, running at ppm only and at 100% power. The antenna used with the oplink is a sh77 diamond (or whatever it's called), on the revo side I use the stock one. That said, the indicator shows about -20db with both devices literally next to each other.
But since this was just a quick test, the leads of the antenna just hang around and were not pointed in any certain direction or fixed in a right angled position. Is this normal or should I look into my setup?

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Title: Re: OPlink Vehicle control looses it
Post by: zukenj on April 28, 2016, 04:48:08 pm
I'm curious about the result :)

That what i asked here: https://forum.librepilot.org/index.php?topic=1332.msg9734#msg9734
At least you can know the wrong device if the RF power is the issue.

From tests i did here i got around 100m where the link is completely lost, with minimal power (1.25mW)

Your post gave me the idea, on using 2 laptops to monitor the dB. I don't have the result yet, because it took me 2 and 1/2 hours to compile next in the second laptop, so I end up at 1:30 AM, and went to bed.
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on April 29, 2016, 05:46:20 am
Here is the video with the OPLink issue.

https://www.youtube.com/watch?v=HN0u_q65SC0 (https://www.youtube.com/watch?v=HN0u_q65SC0)
Title: Re: OPlink Vehicle control looses it
Post by: f5soh on April 29, 2016, 07:29:56 am
Looks like your Oplink Mini do not transmit as expected.
Be sure all antenna side is ok, open the case and inspect solder joins.
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on April 29, 2016, 03:43:38 pm
Thanks f5soh (L).

I will do that, tonight and post back.

Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 04, 2016, 04:27:46 am
I don't see ane solder problem. Please check if you see any suspicious one.
Title: Re: OPlink Vehicle control looses it
Post by: f5soh on May 04, 2016, 07:21:37 am
There a missing coil.
Usually this component is used to power a RF stage, make sense if no range.

Edit: Look like this coil is used for the small "G4C" component, the Tx/Rx antenna switch.
http://datasheet.octopart.com/UPG2179TB-E4-A-NEC-datasheet-26379.pdf

(https://forum.librepilot.org/index.php?action=dlattach;topic=1332.0;attach=2860)
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 04, 2016, 10:01:14 pm
I see.  :'(

Picture from AliExpress Coil.png


Picture from banggood.com Coil_2.png
Title: Re: OPlink Vehicle control looses it
Post by: hwh on May 04, 2016, 10:14:45 pm
Complain to the seller, maybe they'll replace it.

If not the entire RFM22b module runs about $6 US on eBay if you can solder.
Title: Re: OPlink Vehicle control looses it
Post by: Brian on May 04, 2016, 10:41:22 pm
It's not easy to desolder those modules.  You really have to heat both sides at once, which means a very large nozzle on a hot air gun, which means that many more parts might come undone as well.  Carefully working it with a solder sucker and/or wick might work, but I'm not sure it's worth it.
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 05, 2016, 03:21:24 am
Hwh,

Do you have a link just in case?


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Title: Re: OPlink Vehicle control looses it
Post by: hwh on May 05, 2016, 03:34:58 am
The auctions vary all the time, just search eBay for RFM22b.   You want the 433 MHz version with the small crystal (the S2 version).  It shouldn't cost more than around $6 US.  If you're in the US there are several sellers here, the last ones I picked up a few months ago were from a place in Texas I think.

Brian is right, they are hard to get off without lifting pads from the main board.  I had to superglue down a pad I lifted on a similar module. Fortunately it didn't break the trace, just lifted it off the board.
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 05, 2016, 04:52:41 am
hwh,
Thanks.

I contacted Banggood, and send them a video with the issue.

Will see what they will do.

What about this one:

http://www.ebay.com/itm/RFM22B-433Mhz-Wireless-Transceiver-from-HopeRF-/172052713043?hash=item280f240e53:g:~ooAAOxyRNJScbQk (http://www.ebay.com/itm/RFM22B-433Mhz-Wireless-Transceiver-from-HopeRF-/172052713043?hash=item280f240e53:g:~ooAAOxyRNJScbQk)
Title: Re: OPlink Vehicle control looses it
Post by: hwh on May 05, 2016, 05:14:53 am
Yes, that's the one.  And that's the company I picked up the last few I ordered from.

Banggood is funny about the videos, apparently customer service asks for them and someone technical reviews them and says ok it's bad.  Usually they'll ship a replacement and you get to keep the bad one.
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 05, 2016, 02:36:59 pm
Banggood email me, asking if it was ok to send me a new one.

Hope the new one is right, otherwise I will have to go to the desolder route...

:)
Title: Re: OPlink Vehicle control looses it
Post by: f5soh on May 05, 2016, 03:28:47 pm
The missing component is a 18nH inductor, 0402 format

Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 05, 2016, 03:35:07 pm
Laurent,

I am hopping that the new OPlink have the component in place.

 ::)

Title: Re: OPlink Vehicle control looses it
Post by: f5soh on May 05, 2016, 03:40:35 pm
Just say that for the one you have already, instead of replace the module.
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 05, 2016, 04:17:25 pm
Laurent,

Do you think that they replace the coil one for a Thin Film inductor?
Title: Re: OPlink Vehicle control looses it
Post by: f5soh on May 05, 2016, 05:02:44 pm
Except this one, the others inductors already mounted are Thin Film inductors.

If you can find a 18nH value, try to add the missing inductor.
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 05, 2016, 05:05:45 pm
I am looking for a hot air soldering station, and I'll see if I can replace it.
Title: Re: OPlink Vehicle control looses it
Post by: f5soh on May 05, 2016, 05:14:22 pm
With a thin soldering iron you can do the job also :)
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 05, 2016, 06:11:29 pm
You are GOOD. It is really small. Lol

Sent from my SM-N900P using Tapatalk

Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 24, 2016, 04:35:53 am
I received my replacement OPLink from banggood, and it is working great. I checked the the coil was there and it is.


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Title: Re: OPlink Vehicle control looses it
Post by: darkdave on May 24, 2016, 07:53:28 am
I received my replacement OPLink from banggood, and it is working great. I checked the the coil was there and it is.
https://forum.librepilot.org/index.php?topic=1332.0

Glad you fixed your problem, can you send me the link to your supplier? Banggood? Please send me a link to their page and their Standard Revolution board sell page.

I want to talk to them and negotiate to resell their products on ebay:
https://forum.librepilot.org/index.php?topic=1652.0

May I assume that they have now fixed their problems with not just the oplink 433mhz stability issues but also their barometer?
https://forum.librepilot.org/index.php?topic=311.0

Also even if the 433mhz oplink issue is resolved, sometimes inevitably we will still have signal lost and reconnect. I have been doing some prop off testing on my QAV250 Chinese clone and discovered some disturbing issues: When I turn my transmitter back on and re-establish the link: The fail safe is interrupted and power offs for 2 seconds before the transmitter can take control of the drone again. That is 2 seconds of free fall time! This situation is made worst if you have to perform an arming action that consumes more time. What this means is that its better to let the drone complete its fail safe return to base and land sequence before reconnecting the controller to it. If your drone has no landing sequence then its a big problem.

Please send me the links to this supplier so I can contact them. I'm in China so I can negotiate.

Regards, David
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 25, 2016, 08:23:08 pm
David,

I you negotiate please don't drag prices up. It is a expensive hobby already. :)

Site:
http://www.banggood.com/ (http://www.banggood.com/)

Contact:
http://www.banggood.com/Contact-Us_hi111 (http://www.banggood.com/Contact-Us_hi111)
Title: Re: OPlink Vehicle control looses it
Post by: darkdave on May 26, 2016, 07:18:48 am
This looks like an ebay style website, and you say they actually manufacture the things they sell?
Title: Re: OPlink Vehicle control looses it
Post by: darkdave on May 26, 2016, 09:43:00 am
Looks like your Oplink Mini do not transmit as expected.
Be sure all antenna side is ok, open the case and inspect solder joins.

The prevalent issue of the missing inductor: That is on the Ground Control Station side correct? The Oplink on the ground?

Are there any hardware faults on the Revolution board it self or the Oplink mini Air?

Also has anyone checked to see if the Oplink mini GROUND has the same problem? If not it might be a good idea to only buy Oplink Mini Ground instead of the standard Oplink.

Title: Re: OPlink Vehicle control looses it
Post by: darkdave on May 26, 2016, 10:16:18 am
Here is the video with the OPLink issue.

https://www.youtube.com/watch?v=HN0u_q65SC0 (https://www.youtube.com/watch?v=HN0u_q65SC0)

I can't see it, youtube says the video is private!!

Anyways I have range problems too but I opened up my standard oplink and I do see what looks like a blueish component bridging the 2 solder joints where you guys say the coil is ment to be, I guess that means my standard oplink has a coil. Could it be that the problem is also somewhat common also on the drone side of things ie. the flight controller not receiving because it's also missing some coil or other component?
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 28, 2016, 11:41:00 pm
I never say they manufacture it. I bought it from them


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Title: Re: OPlink Vehicle control looses it
Post by: darkdave on May 28, 2016, 11:54:05 pm
I never say they manufacture it. I bought it from them


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Can you tell us the name of the seller?
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 29, 2016, 12:30:14 am
http://us.banggood.com/Wholesale-Warehouse-OpenPilot-OPLINK-MINI-CC3D-REVO-Universal-Transceiver-TX-RX-Module-Integrating-Remote-Controller-wp-Usa-1000081.html

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Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 29, 2016, 12:33:40 am
That is the one i bought

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Title: Re: OPlink Vehicle control looses it
Post by: darkdave on May 29, 2016, 12:38:14 am
Quote
That is the one i bought
Any barometer problems or telemetry (433mhz) reception issues from this seller?
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on May 31, 2016, 07:50:37 pm
On the OPLink yes, and they replace it. The new board works great.
Title: Re: OPlink Vehicle control looses it
Post by: darkdave on May 31, 2016, 10:53:20 pm
Quote
On the OPLink yes, and they replace it. The new board works great.

Who is the seller? Do you know the handle or name of the seller from banggood? Do sellers have a unique identity just like in Ebay?
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on June 01, 2016, 03:33:27 pm
Guys, is it possible to tell which side is faulty? (oplink or revo)
I've checked the signal level and it drops after 10-15meters and completely lost after 30m.
First I plugged in my revo and walked away with the oplink powered, then plugged in my oplink and walked away with the quad. Both had the same result.

Here's a pic of my oplink: https://drive.google.com/open?id=0B_2MdV3di_UMOXJxWmVYSTZoM2s (https://drive.google.com/open?id=0B_2MdV3di_UMOXJxWmVYSTZoM2s)
Title: Re: OPlink Vehicle control looses it
Post by: hwh on June 01, 2016, 05:06:11 pm
I would bet that one is bad, every one I purchased that has the chip id ground off was bad.  The RFM22b board on that oplink isn't a genuine one made by Hope RF, it's a clone.  All of the clone RFM22b boards I had were off frequency.  I fixed the oplinks by replacing the RFM22b and they worked fine after that.

As for testing which end has low power f5soh explained it in another thread:
...You can test connecting computer to Oplink, next to Revo and compare the Rssi level on both sides.
Set same power on both sides, maintain same position and you can see which device is wrong.
When Revo is connected to computer you can power the oplink with a usb cable plugged in phone charger module.
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on June 01, 2016, 06:08:40 pm
So, I did some testing again:

Oplink connected to desktop pc, shows: -127
Revo connected to laptop, shows: -40~-55


After powering the quad with the battery, they shows the same values: ~ -40 (about 3meters away)

The oplink shows fix -55, the revo is jumping between -39 and -55

The flight data on the oplink side doesn't update. (i think that's why the -55 signal level is fixed) <- doesn't update if both sides are connected to gcs..

If I power up the revo then the oplink, the oplink doesn't show the signal level :S

Does that mean that my oplink is dead?

EDIT:

New values:

Oplink connected to laptop, revo about 15-20meters away, shows about -61

Revo connected to laptop, oplink about 15-20meters away, shows about -52

These are quite low values for such a short distance, or not?
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on June 01, 2016, 09:37:20 pm
It may refer to the same test (the Modem in the Revo and the OPLink are the same, so ether can be Coordinator), the way I did it was:


Do the same in an apposite way, move around and check the signal.

That will tell you witch one is the one that is failing.


I would bet that one is bad, every one I purchased that has the chip id ground off was bad.  The RFM22b board on that oplink isn't a genuine one made by Hope RF, it's a clone.  All of the clone RFM22b boards I had were off frequency.  I fixed the oplinks by replacing the RFM22b and they worked fine after that.

As for testing which end has low power f5soh explained it in another thread:
...You can test connecting computer to Oplink, next to Revo and compare the Rssi level on both sides.
Set same power on both sides, maintain same position and you can see which device is wrong.
When Revo is connected to computer you can power the oplink with a usb cable plugged in phone charger module.
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on June 03, 2016, 01:55:03 pm
It may refer to the same test (the Modem in the Revo and the OPLink are the same, so ether can be Coordinator), the way I did it was:

  • Power the Revo, USB connected to GCS and configure it for power and as Coordinator, save and re-boot the Revo.        Take note on the Coordinator number, unplug from USB.
  • Plug the OPLink, and uncheck the Coordinator box, save and reboot the OPLink, input the Coordinator number from Revo, save and unplug from USB.
  • Power the OPLink using a USB Phone charger.
  • Plug the Revo to the PC running GCS, move around and check the signal.

Do the same in an apposite way, move around and check the signal.

That will tell you witch one is the one that is failing.

If I set the revo as the coordinator it doesn't show anything on the oplink tab, but it shows -40 if I plug the oplink into the pc.
If the oplink is the coordinator, both side shows around -40 for signal.

Does that mean that the revo is the dead one?
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on June 03, 2016, 04:39:01 pm
When I did my test, the signal from the Revo was really strong, the I posted pictures of the OPLink, and f5soh spoted a missing component.

You need to inspect the Revo. Take closeup pictures from both sides of the Revo, and post them, to see if someone spot something.

Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on June 04, 2016, 09:47:29 am
When I did my test, the signal from the Revo was really strong, the I posted pictures of the OPLink, and f5soh spoted a missing component.

You need to inspect the Revo. Take closeup pictures from both sides of the Revo, and post them, to see if someone spot something.

Thanks, I'll have to disassemble the whole thing (the revo is in the middle of my 450 quad), I will post photos if I had time to take the whole thing apart :D
I will finally have a reason to disassemble and clean up the wiring a little :D
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on June 06, 2016, 04:16:54 pm
Attached photos of two sides
(http://uploads.tapatalk-cdn.com/20160606/8f129a1d66a9fbdc886e05cd1bfd1522.jpg)(http://uploads.tapatalk-cdn.com/20160606/233c2e09d6e1565948419491d989b0c6.jpg)
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on June 06, 2016, 09:18:02 pm
I don't see and issue, but will be nice if f5soh or hwh can look at it to see if they are able to spot something.
Title: Re: OPlink Vehicle control looses it
Post by: hwh on June 06, 2016, 10:24:46 pm
I don't seen anything obviously wrong with the board.

The only problem I have with it is I think the RFM22b radio module is a Chinese clone of the Hope RF module.  Two of the three I have that look like that were so far off frequency they wouldn't talk to oplinks that were on the proper frequency.  There are three reasons I think they're clones.
One of the three I have like that works, the other two I had to replace.  They're the same design as the Hope ones, they just seem to be lower quality.

Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on June 06, 2016, 11:13:58 pm
I don't seen anything obviously wrong with the board.

The only problem I have with it is I think the RFM22b radio module is a Chinese clone of the Hope RF module.  Two of the three I have that look like that were so far off frequency they wouldn't talk to oplinks that were on the proper frequency.  There are three reasons I think they're clones.
  • The castleations on the edge of the board, real ones have a square inside edge.
  • The silkscreen is larger type.
  • The markings on the RF chip have been removed. Genuine Hope ones have their proprietary part number on them.
One of the three I have like that works, the other two I had to replace.  They're the same design as the Hope ones, they just seem to be lower quality.

So the best would be if I buy two original radio modules and replace the clones with them?
Title: Re: OPlink Vehicle control looses it
Post by: hwh on June 07, 2016, 01:18:10 am
I can only tell you my experiences with them.  I'm an amateur radio operator so I had the equipment on hand to test and make sure mine were bad before I replaced them.  I can only guess about your equipment.

I have 6 spare RF modules (2 - 433MHz, 2 - 915MHz, and 2 433MHz 1w) and 6 on boards (5 on oplinks, 1 on a revo). Of them all but one match as far as silkscreen, castleations, and chip markings.  The one that doesn't match I think is a clone but it does work.  Two of the oplinks originally had "clone" RFM22b modules and didn't work until I replaced the modules.  After replacement they worked perfectly.

The RFM22b modules are fairly inexpensive, I think I paid around $7 US for each one on eBay (a seller in Texas whose name is something like arduino but isn't exactly that).
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on June 07, 2016, 10:34:12 am
I can only tell you my experiences with them.  I'm an amateur radio operator so I had the equipment on hand to test and make sure mine were bad before I replaced them.  I can only guess about your equipment.

I have 6 spare RF modules (2 - 433MHz, 2 - 915MHz, and 2 433MHz 1w) and 6 on boards (5 on oplinks, 1 on a revo). Of them all but one match as far as silkscreen, castleations, and chip markings.  The one that doesn't match I think is a clone but it does work.  Two of the oplinks originally had "clone" RFM22b modules and didn't work until I replaced the modules.  After replacement they worked perfectly.

The RFM22b modules are fairly inexpensive, I think I paid around $7 US for each one on eBay (a seller in Texas whose name is something like arduino but isn't exactly that).

I think this is the seller you said: http://www.ebay.com/itm/RFM22B-433Mhz-Wireless-Transceiver-from-HopeRF-/172052713043?hash=item280f240e53:g:~ooAAOxyRNJScbQk (http://www.ebay.com/itm/RFM22B-433Mhz-Wireless-Transceiver-from-HopeRF-/172052713043?hash=item280f240e53:g:~ooAAOxyRNJScbQk)

I'm going to buy some of these, but the shipping is more expensive than the actual product :D

EDIT:

I've found a shop in my country which has these (originals) for only 5$, and the shipping fee is much cheaper too, yaaaay :D
Title: Re: OPlink Vehicle control looses it
Post by: hwh on June 07, 2016, 02:07:49 pm
Yes, that was the eBay seller I've been dealing with. He's shipped all three orders I've placed with him the next day and all have been genuine Hope modules.
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on June 08, 2016, 07:05:07 pm
The replacement arrived, and I've already soldered them, it binds, and looks better, but now I just tested them while they were like 1 meter away, the signal strength was -20.

It looks like that the radio problem is fixed, but I have an other:

If I power the oplink from the main or flexi port, the tx and rx leds are blinking. Tried with 3.6V to 5V. At 5V the tx/rx and the Link blinks after each other. Did I cook something when I soldered the new RF module back? :S

It's working from the USB port.
Title: Re: OPlink Vehicle control looses it
Post by: zukenj on June 08, 2016, 08:37:25 pm
I use my connected to the USB port. Not to control the quad, just for configuring it.
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on June 09, 2016, 01:29:06 pm
I'd like to test the ppm feature of the oplink (again), but If I power up the oplink from usb, it doesn't give power to the connected RX :S
Title: Re: OPlink Vehicle control looses it
Post by: chromvis on June 09, 2016, 08:03:50 pm
Just read this thread. I have two quads with revo and OPLink control I was flying them OK not so far although and was able to autotune etc., but this problem seem serious so I did simple walk test.
Setup 1:  Revo with 17.6 cm polarized antenna (Active - vertical, ground - horizontal), Transmitter: Radiolink (RF OFF, OPlink module attached on the back to trainer port with UBEC 5V and Bluetooth module with stock coil-type antenna).   Set quad on the table and walk away with TX and laptop. In about 20 m away signal was lost for a second then again. At 30 m distance signal was lost completely. There was no fading bar was in the mid-level and than gone.
Setup 2:  Revo with similar polarized antenna (original from OpenPilot June 2015), Transmitter FlySky with replaced RF module (OPlink witn UBEC and Bluetooth) polarized antenna 17.5 cm active vertical with dual horizontal ground wires. Same walking test. Result slightly different: in about 20 - 25 m GCS lost signal on the bottom right corner and the whole OPLink panel went blank. Walking back restore connection and OPlink panel got reloaded.
I inspected both OPLinks - coils are in place. I will swap coordinators to cross transmitters and retest. But I already have doubt in reliability to this setup.
Title: Re: OPlink Vehicle control looses it
Post by: chromvis on June 09, 2016, 08:20:25 pm
Swap transmitters - results are even worse. Signal loose at about 10 meters. Could it be an interference with telemetry (PPM + telemetry)? It seems to be not a radio transmission problem, but rather processor problem. Complete sudden loss of signal appears at 50 - 60 dB.
Title: Re: OPlink Vehicle control looses it
Post by: km4lkx on July 18, 2016, 02:09:47 pm
Does lowering the baud rate of the oplinks increase the range at all? My quad dropped out of the sky as soon as it reached about 50 meters out.
Title: Re: OPlink Vehicle control looses it
Post by: f5soh on July 18, 2016, 03:35:29 pm
Yes, lowering baudrate increase the range because the signal bandwidth is smaller.
Using PPM Only the baudrate is automatically set to 9600bauds.

As reference the last limit where the link disconnect is around 80m with 1.25mW and 57600bauds.

Double check antennas and connectors.
Title: Re: OPlink Vehicle control looses it
Post by: nitromethane on July 18, 2016, 03:39:01 pm
Does lowering the baud rate of the oplinks increase the range at all? My quad dropped out of the sky as soon as it reached about 50 meters out.

Yes, somewhat, but at a distance of 50m the link should should be strong and reliable at maximum baud rate setting.

How do you have your antennas set up?
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on September 09, 2016, 01:48:32 am
Hi guys!

Could you please link me some antennas for the oplink and the revo? (I think the ones that came in the package is rubbish)
Thanks!
Title: Re: OPlink Vehicle control looses it
Post by: Brian on September 09, 2016, 04:14:34 am
I really like the Diamond antenna for the Tx side: http://www.readymaderc.com/store/index.php?main_page=product_info&cPath=11_45_46_50&products_id=1200

and "sanders-style" monopoles on the Rx side: http://www.readymaderc.com/store/index.php?main_page=product_info&cPath=11_45_46_50&products_id=3001
Title: Re: OPlink Vehicle control looses it
Post by: kennyevo on September 09, 2016, 11:39:17 am
I really like the Diamond antenna for the Tx side: http://www.readymaderc.com/store/index.php?main_page=product_info&cPath=11_45_46_50&products_id=1200

and "sanders-style" monopoles on the Rx side: http://www.readymaderc.com/store/index.php?main_page=product_info&cPath=11_45_46_50&products_id=3001

Awesome, thanks!