LibrePilot Forum
General Category => General Discussion => Topic started by: sv2fpv on June 30, 2017, 08:28:20 pm
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Hi
My question, can connect unidirectional rf amplifier on OpLink mini?
Setting OpLink mini only control ppm as coordinator
Setting Revo only control ppm as Receiver
Is that right to work?
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I think that is correct; that in this case the receiver does not send acknowledgements.
Of course you can test this. Set both ends to say 1mw and determine the range. Then set just the transmitter end to a much higher power and make sure the range significantly increases.
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"I think that is correct; that in this case the receiver does not send acknowledgements" I don't know if that is sure.
Tested with 7 watt amplifier
At 100mw in, out is 6 watt.
Not flying tested but in range of 50meter
100mw = 9 +20 on Gcs
6watt = 9 +60 on Gcs
Thanks
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The question is whether the receiver sends acknowledgements back. Just measuring the received power doesn't answer that question.
If you test like I suggest, you can be sure that you don't need to increase power on the receiver as well. I am almost certain that you don't need to increase power on the receiver for the setup you discribe, but this is a way to test any system.
I get about 300m at 1.6mw with omni antennas. That is 2-3 km at 100mw.
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(It wouldn't let me edit the previous message.)
It is important to have good antenna systems, especially at high power. Interference can be a real problem even at 100mw.
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interference have at 6watt but at 3-4 watt is ok, tested with stock antenna, next step with custom antenna.
Oh i don't believe that 1.6 mw 300 meters data transfer.
Anyway thanks
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I have good omni antennas and a flight log to back it up. I will try to dig it up and post it here.
Edit:
Here is a screen capture of the logged flight. For this flight, the max distance was more like 260 meters (don't forget to calculate as sqrt(x^2+y^2+z^2)), but it also was never out of range, even with all the stunts I did that flight. It did have some dropped packets. At the end of the flight, you can see where I disconnected the flight battery; the RSSI went to -127 and RxGood went to 0 just before I stopped logging, yet it was better than that the whole flight. When the link is completely lost RSSI goes to -127 and RxGood goes to 0.
This is with vertically oriented linearly polarized omni antennas. I used a Nagoya 771 on the ground and a Nagoya 701 in the air (didn't even have ferrite beads). These are not ideal because they really need a ground plane / counterpoise. Simple dipoles like the stock OP antenna would be better than these.
Home was in the center of the runway, but the GCS/OpLink was off to the side of the runway. I was flying mainly up and down the runway and on the far side of the runway and the actual distances would be slightly farther than logged.
Screen cap shows x, y, z distances from Home, OpLink RSSI, OpLink RxGood (number of good packets in last 64 packets).
(https://forum.librepilot.org/index.php?action=dlattach;topic=3616.0;attach=6303)
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If the radios are configured for control only, then that is unidirectional. Acks are not used in either case, and I'm pretty sure that, even in the bi-directional case, control information will always be received correctly as long as the Rx can receive from the Tx, but, of course, no data can be sent the other direction.
That said, what country are you in? Most regions have restrictions on 433 MHz that limit the power used, and you really shouldn't need more that a watt.
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Thanks
Maybe have interference from amateur radio repeaters
Amateur radio band 430-440 mhz
Flight test, 3 watt next days.
Have a good day.
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The Ham radio 70cm band is indeed 430-440Mhz but you should take in account the IARU band plan, especially using this power levels:
https://www.iaru-r1.org/index.php/spectrum-and-band-plans/uhf/70-centimeter
Avoiding repeater inputs and sat up link, configured channels 85-124 (433.400-434.960Mhz) will be a good candidate.
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Yes that is my choice, more wide 50 - 150
Repeaters have very strong signals in all open area in the town
About 437-439 rx tx
About 431-434 rx tx
426 - 427 tetra(dataVoiceRepeater)very strong signal
Next days testing with custom antenna and 3 watt tx, 85-124 channels
Please tell me if that is right "If the radios are configured for control only, then that is unidirectional. Acks are not used in either case"
Thanks for all answers
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Read my post above. ACKs are not used in any case.
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Isn't it more accurate to say that Acks are used with some forms of telemetry, but never with "control only"?
Also, for long range unidirectional "telemetry only" you may want to try setting the model as Coordinator and making it's transmit power be the higher one. This may or may not work well as the high priority coordinator task can fight with with the high priority stabilization task for time critical CPU access. Is this task priority issue tracked to be worked on?
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Ok Brian i understand it, it does not have ack, thanks.
Oh Cliff thanks i understand it.
I do not want the telemetry, but I can try it, with another receiver(2.4ghz) for control.
All working fine
osd = ok
only control(3watt TX) = ok (not tested in flight range)
very good position Hold
Little problem with the compass, oscillating in gps mode in all directions
Thanks
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Is the compass oscillating or is the vehicle oscillating or both?
You really need an external compass and still must carefully twist all power (high current) cables.
There is also a different GPS oscillation issue that happens with some DJI/Naza GPS/compass.
https://forum.librepilot.org/index.php?topic=3012.msg21154#msg21154
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Vehicle oscillating in all directions in GPS modes.
With M8N GPS and 15.09 release with external compass no oscillating
https://forum.librepilot.org/index.php?topic=1110.0
With 16.09 and M8N big problem, oscillating and drift to North
back to 15.09 same problem.
16.09 with NEO M6 is fine no drifting , a little oscillating standard frequency.
Can i test the firmware? Naza GPS. Or does not.
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That firmware only helps DJI/Naza GPS issue.
One possible cause for your issue is bad mag calibration. Mag calibration is continuous, even between pressing the button 6 times. It gathers data all the time, not just when the progress bar is moving.
Use "aux mag only" setting (Attitude -> Magnetometer). Mag must be green most of the time, even while flying. Never ever red at all.
During mag calibration:
- setting the quad on the ground at any time during mag calibration is bad
- setting the quad on anything metal (like your car) during mag calibration is bad
- you really need to use RF telemetry to do calibration, not USB cable
- generally hold it chest high the whole time while someone else runs the GCS and tells you how to point the quad
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So I really do it.
This is a big story.
"Basic (Complementary)" it flies brilliantly, no oscilating no drift.
I tried with different distances of the compass from the boat 10-15-20 cm, same problem
Many times and in different parts i did calibration(16.09), but always the same problem.
The best was with the NEO M6. The compass is always green at GCS only full throttle becomes orange.
PosHold very good position but little oscillating in all directions, GPS modes all fly very well
Now I expect them to try
http://www.ebay.com/itm/APM2-6-HMC5983-High-Precision-Compass-External-Magnetometer-Temperature-CA/142065025612?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649 (http://www.ebay.com/itm/APM2-6-HMC5983-High-Precision-Compass-External-Magnetometer-Temperature-CA/142065025612?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649)
http://www.ebay.com/itm/HMC5883L-GY-273-GY-271-Triple-Axis-Compass-Magnetomet-Sensor-3V-5V-For-Arduino/162491330905?ssPageName=STRK%3AMEBIDX%3AIT&var=461499489738&_trksid=p2060353.m2749.l2649 (http://www.ebay.com/itm/HMC5883L-GY-273-GY-271-Triple-Axis-Compass-Magnetomet-Sensor-3V-5V-For-Arduino/162491330905?ssPageName=STRK%3AMEBIDX%3AIT&var=461499489738&_trksid=p2060353.m2749.l2649)
Have a nice day
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Isn't it more accurate to say that Acks are used with some forms of telemetry, but never with "control only"?
Also, for long range unidirectional "telemetry only" you may want to try setting the model as Coordinator and making it's transmit power be the higher one. This may or may not work well as the high priority coordinator task can fight with with the high priority stabilization task for time critical CPU access. Is this task priority issue tracked to be worked on?
Unless something has changed, Acks are not used in any configuration of OPLink communications.
I believe the option for a one-way telemetry (data) connections has been removed, at least from the GUI. Are you suggesting that you would like to have a telemetry link that is longer than your control link? Do we / do we really want to support a totally autonomous mode where you have no control link to the aircraft?
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Some UAVOs are acknowledged? They are retransmitted if not acknowledged. Perhaps we are talking about two different levels, you the low level ack?
for long range unidirectional "telemetry only"
You can set the model to be coordinator, run it at high power, run the GCS at low power. You get telemetry received, but GCS isn't successful when it sends. But as I say, this seems to now have a bug in that the high priority RF task needs real time like the stab code does.