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Old Mar 09, 2011, 02:49 PM
Ikaruswannab
Joined Sep 2009
978 Posts
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2.4GHz Rc range test

Hi,
Yesterday i tested my FPV setup of 1280MHz Video link and 2.4GHz RC that ended with an uncontrollable plane hitting the ground.
I have read in this forum that the above is a safe choice but it seems it isn`t.
I am using the FOX-800 systems in pair with
http://www.hobbyking.com/hobbyking/s...idProduct=9042 of a friend that was flying in the same field.
His easystar lost its nose and i lost my confidence to fly with it again.
Anybody has a clue what went wrong and how to fix it (w/o Low pass filters)
I must add that my servos never jittered and VTx had a separation of about 20cm from the RC Rx.
Thank you.
Teo
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Old Mar 09, 2011, 02:53 PM
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Daemon's Avatar
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Quote:
Originally Posted by teopbako View Post
Anybody has a clue what went wrong and how to fix it (w/o Low pass filters)
You already know the answer to your own question. What prevents you from
using a low pass or notch filter?

ian
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Old Mar 09, 2011, 02:54 PM
It's pronounced Caveman...
Reno, NV
Joined Nov 2009
437 Posts
2.4Ghz with 1280Mhz video can be a safe choice IF you're using a good 2.4Ghz system that is frequency-hopping and if you are using a low pass filter. Your video tx could easily be interfering with your 2.4Ghz system. What kind of range did you get with your ground tests?
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Old Mar 09, 2011, 02:54 PM
Ikaruswannab
Joined Sep 2009
978 Posts
Quote:
Originally Posted by Daemon View Post
You already know the answer to your own question. What prevents you from
using a low pass or notch filter?

ian
The fact that many people have reported a trouble free operation with the
FOX-800 system and of course the extra cost
Teo
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Old Mar 09, 2011, 02:57 PM
Ikaruswannab
Joined Sep 2009
978 Posts
Quote:
Originally Posted by c4v3man View Post
2.4Ghz with 1280Mhz video can be a safe choice IF you're using a good 2.4Ghz system that is frequency-hopping and if you are using a low pass filter. Your video tx could easily be interfering with your 2.4Ghz system. What kind of range did you get with your ground tests?

As ground testing is concerned i could go more than 30m away without problem.
What is acceptable??
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Old Mar 09, 2011, 03:05 PM
It's pronounced Caveman...
Reno, NV
Joined Nov 2009
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Originally Posted by teopbako View Post
As ground testing is concerned i could go more than 30m away without problem.
What is acceptable??
Personally I ground test (With the video on, and with a heatsink attached or a fan blowing on it) out to the range I want to fly. I've ground-tested out to 2KM with my setup, so that's as far as I'm willing to fly in THAT environment. Is the hobbyking 2.4Ghz system a FHSS system?
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Old Mar 09, 2011, 03:06 PM
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Lakewood, Colorado
Joined Aug 2002
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Quote:
Originally Posted by teopbako View Post
The fact that many people have reported a trouble free operation with the
FOX-800 system and of course the extra cost
Teo
You have to put everything in the proper context. A lot of people are using
frequencies they shouldn't, closer to 1Ghz than 1.2Ghz with that Tx,
and they're using something other than the very cheapest 2.4Ghz systems available
(cheap 2.4ghz Rx's have inferior input filtering).

That said, the only truly safe, reliable, proven option is to add the low pass
or notch filter. It's not expensive at all when compared to
the possibility of losing the whole plane.

ian
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Old Mar 09, 2011, 03:11 PM
Ikaruswannab
Joined Sep 2009
978 Posts
Quote:
Originally Posted by c4v3man View Post
Personally I ground test (With the video on, and with a heatsink attached or a fan blowing on it) out to the range I want to fly. I've ground-tested out to 2KM with my setup, so that's as far as I'm willing to fly in THAT environment. Is the hobbyking 2.4Ghz system a FHSS system?
The strange thing is that the plane froze up at distances closer than 30m.
You ground test at 2Km.
Is that LOS?
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Old Mar 09, 2011, 03:12 PM
Ikaruswannab
Joined Sep 2009
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Originally Posted by Daemon View Post
It's not expensive at all when compared to
the possibility of losing the whole plane.

ian
That is SOOOO true.
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Old Mar 09, 2011, 03:17 PM
It's pronounced Caveman...
Reno, NV
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Quote:
Originally Posted by teopbako View Post
The strange thing is that the plane froze up at distances closer than 30m.
You ground test at 2Km.
Is that LOS?
Did you ground test your radio at 30M with the video tx on?

And yes, I set the plane on a plastic surface about 3ft off the ground, hopped in my Jeep and drove to a LOS point 2km away as indicated by Google and operated both video and RC control within the jeep with it running. So in a non-optimal condition (inside a vehicle, with my cell phone, with the vehicle and it's alternator running and generating whatever amount of rf noise that is generating) I was able to control my model and see video while rotating both my RC TX and my video RX antennas. But I'm using a low pass filter, and a 1W boosted 2.4Ghz FrSky FHSS system.
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Old Mar 09, 2011, 03:23 PM
Ikaruswannab
Joined Sep 2009
978 Posts
Quote:
Originally Posted by c4v3man View Post
Did you ground test your radio at 30M with the video tx on?
Yes the Video Tx was running.
But the truth is that i did the range test after the crash.
My friend was holding the plane and i was standing next to the video Rx where i was when flying and he walked until the crash point and past that wit no RC loss or what so ever.
I will try your way (Car drive away) next time.
Teo
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Old Mar 09, 2011, 03:27 PM
It's pronounced Caveman...
Reno, NV
Joined Nov 2009
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Quote:
Originally Posted by teopbako View Post
Yes the Video Tx was running.
But the truth is that i did the range test after the crash.
My friend was holding the plane and i was standing next to the video Rx where i was when flying and he walked until the crash point and past that wit no RC loss or what so ever.
I will try your way (Car drive away) next time.
Teo
Looks like the HK 6CH 2.4Ghz receivers don't have diversity. Make sure the antenna isn't being blocked by anything such as batteries, carbon fiber, etc.

Also, not sure how well that RC system will work for FPV. No diversity, unknown TX power (could be 10mw for all you know, since I believe some countries limit it to 10mw), might not be spread spectrum...

Might want to fly non-fpv for awhile and make sure that RC system even works at 200 meters without fpv gear on it... Pretty much everyone advises that you should fly the model non-FPV to make sure there's no issues before attempting FPV flight with it. Also, test, test, test, and re-test after that. An ounce of prevention saves 2 ounces of glue! I found that out when I re-launched my plane after landing without checking everything over. Ended up the elevator joint had failed and I crashed shortly after.
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Last edited by c4v3man; Mar 09, 2011 at 03:34 PM.
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Old Mar 09, 2011, 03:35 PM
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Joined Dec 2009
385 Posts
I have almost the exact same setup. 1280 Mhz 800w Vtx Fox. Futaba 2.4 Ghz Full range receiver (two antennas at the right angles)

Problems with freezing controls even 150-200 meters away sometimes.
Never been more than 350 meters away, because I am scared of loosing control of the plane. Video quality is great though. No jittering of servos. I have flown the plane to a tiny dot i size without the video turned on.

It is basically nervewrecking like this

I have grounded my plane till the DragonLink comes (takes a long time to get it )

I will not get the 45$ low pass filter since I ordered the DL.

Will have to be satisfied with my EDF Jet and a normal SkySurfer in the mean time.
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Old Mar 09, 2011, 03:45 PM
Ikaruswannab
Joined Sep 2009
978 Posts
Quote:
Originally Posted by c4v3man View Post
Looks like the HK 6CH 2.4Ghz receivers don't have diversity. Make sure the antenna isn't being blocked by anything such as batteries, carbon fiber, etc.

Also, not sure how well that RC system will work for FPV. No diversity, unknown TX power (could be 10mw for all you know, since I believe some countries limit it to 10mw), might not be spread spectrum...

Might want to fly non-fpv for awhile and make sure that RC system even works at 200 meters without fpv gear on it... Pretty much everyone advises that you should fly the model non-FPV to make sure there's no issues before attempting FPV flight with it. Also, test, test, test, and re-test after that. An ounce of prevention saves 2 ounces of glue! I found that out when I re-launched my plane after landing without checking everything over. Ended up the elevator joint had failed and I crashed shortly after.
It has been used non-FPV for almost a year now to as far as human eyes can see it without problems.
I am also waiting for my DL to be used with my long range Easyglider that will be using 2.4GHz for video.
I only bought the FOX unit so that i can fly FPV at the same field chasing my budies.
No luck so far.
Teo
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Old Mar 09, 2011, 03:54 PM
It's pronounced Caveman...
Reno, NV
Joined Nov 2009
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You never know... could have even been the BEC in the ESC might have sagged low enough to cause the RC TX to fail during your launch (assuming you crashed during launch).
A low pass filter would definitely be wise, however, even if you're going to use a DL system, since your vid TX may interfere with GPS as well (if you're using an OSD that is).
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