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Old Apr 07, 2012, 10:08 AM
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Switzerland, LU, Buchrain
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Quote:
Originally Posted by WiseDuck View Post
Are you saying you have to use a dedicated battery and whatnot?
No, I'm also using a one battery setup. However, if one (like the other poster and maybe also you) experiences limitted range and want to get to the bottom of the source, it's wise to build a test setup as simple as it gets, then add components up until trouble starts to find which component(s) are causing issues and then to take counter measurements. Such counter measurements may include filtering, shielding or replaceing components completely.
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Originally Posted by WiseDuck View Post
The voltage fluctuations in the main power train is enough to throw off the 5.8ghz equipment?
This MIGHT be in certain cases. Remember, there are almost an unlimited number of configuration combinations out there. FPV is still mostly an DIY thing, so if something works for you, it does not necesairly have to work in a slightly different combination.
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Originally Posted by WiseDuck View Post
I've heard the thing about some cameras being noisy, mine's right up against the video Tx, here's a pic of the setup, ignore the antenna, I've got yours on it right now. Also, I'm using the Hobbyking 200mw 5.8ghz kit.
See, even a very nice/decent build can cause trouble sometimes. Cameras are sometimes troublesome, but frankly speaking 5.8Ghz is probably the band with the fewest issues. According to my experience here are some causes for trouble on 5.8Ghz in no poarticular order:

- unclean power, be it throug ripple from a DC/DC converter or fluctuations caused by the motor load (ESC) etc.
- antenna connectors, antenna cabling. Those SMA connectors sometimes are badly crimped, sometimes not tightened enough and on 5.8G this can make a huge difference.
- direct radiation into the electronics caused by harmonics of other on board components
- very noisy RF envirenoment

This list is probably not complete, but I've seen those in real world a couple of times, sometimes just one, sometimes a mixture of the above.

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Originally Posted by WiseDuck View Post



Here is my usable range at the moment... Also, it's worth noting that without ANY sort of quad, just holding the receiver and goggles in my hand I got 900m out of my own antennas before I had to turn back because lunchtime was over! So it's the quad for sure, something on it...
That's why I suggested to build up a test platform and add component after component with range checks in between to find the component causing the trouble. Btw, your quad looks awesome!
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Originally Posted by WiseDuck View Post

Also, I wouldn't say this is an area full of interference, there are no towers or buildings nearby, it's just a huge empty area.

From what I can see I agree that the area looks clean RF wise. You should get WAY more range there. So as you said, it must be a component on your copter, once you isolate and fix it your range will be there.

Markus
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Old Apr 07, 2012, 11:36 AM
Kiwi in Germany
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Germany
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Originally Posted by msev View Post
Whaka if you have some extra time on your hands you could make a flight test with that 3.3V ubec, so we'll know if that's the issue or not..

Wiseduck you could try a secondary lipo and add some distance between the cam and the tx, and then tell us if the range is still shabby..
I have time after the easter weekend ... I will slap it on a plane and see what I get.
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Old Apr 07, 2012, 11:39 AM
Kiwi in Germany
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Quote:
Originally Posted by markus123456 View Post
No, I'm also using a one battery setup. However, if one (like the other poster and maybe also you) experiences limitted range and want to get to the bottom of the source, it's wise to build a test setup as simple as it gets, then add components up until trouble starts to find which component(s) are causing issues and then to take counter measurements. Such counter measurements may include filtering, shielding or replaceing components completely.

This MIGHT be in certain cases. Remember, there are almost an unlimited number of configuration combinations out there. FPV is still mostly an DIY thing, so if something works for you, it does not necesairly have to work in a slightly different combination.

See, even a very nice/decent build can cause trouble sometimes. Cameras are sometimes troublesome, but frankly speaking 5.8Ghz is probably the band with the fewest issues. According to my experience here are some causes for trouble on 5.8Ghz in no poarticular order:

- unclean power, be it throug ripple from a DC/DC converter or fluctuations caused by the motor load (ESC) etc.
- antenna connectors, antenna cabling. Those SMA connectors sometimes are badly crimped, sometimes not tightened enough and on 5.8G this can make a huge difference.
- direct radiation into the electronics caused by harmonics of other on board components
- very noisy RF envirenoment

This list is probably not complete, but I've seen those in real world a couple of times, sometimes just one, sometimes a mixture of the above.


That's why I suggested to build up a test platform and add component after component with range checks in between to find the component causing the trouble. Btw, your quad looks awesome!


From what I can see I agree that the area looks clean RF wise. You should get WAY more range there. So as you said, it must be a component on your copter, once you isolate and fix it your range will be there.

Markus
I agree that you should be getting more. Here is a trick when you only have one type of camera. The tx you are using has a mic on it. How clear is the audio with camera on and with it off?
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Old Apr 07, 2012, 05:16 PM
Mmmmmmm!
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Kingdom of Sweden, Dalarna County, Sater
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I'll test some of these things tomorrow and also do a proper range check. Maybe I'll take the car and drive until the signal is gone or something. Everything is sitting on a new frame now, don't know if it'll make a difference or not.
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Old Apr 07, 2012, 06:35 PM
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Switzerland, LU, Buchrain
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Quote:
Originally Posted by WiseDuck View Post
I'll test some of these things tomorrow and also do a proper range check. Maybe I'll take the car and drive until the signal is gone or something. Everything is sitting on a new frame now, don't know if it'll make a difference or not.
Make sure to start with the most simple setup you can. I also would like to take the ocasion and add a very important other point to my list:

- unclean power, be it throug ripple from a DC/DC converter or fluctuations caused by the motor load (ESC) etc.
- antenna connectors, antenna cabling. Those SMA connectors sometimes are badly crimped, sometimes not tightened enough and on 5.8G this can make a huge difference.
- direct radiation into the electronics caused by harmonics of other on board components
- very noisy RF envirenoment
- LOS to the antenna! It must be in free airspace and a line of sight must be present from the tx antenna to the rx antenna. Dense builds where everything is very close together may lead to the lipo, a brush less motor, the heat sink of the tx etc. come into the line of sight. On 5.8Ghz this means signal loss as the wavelenght is so short.

Markus
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Old Apr 07, 2012, 07:00 PM
Skint since 2000
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Reading, United Kingdom
Joined Oct 2008
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Quote:
Originally Posted by WiseDuck View Post
Power train? Mine's completely unfiltered and as simple as it gets. I have the F450 frame with the built-in power distribution board, that supplies power to all motors. I also have a JST connector on one pad and that feeds power to the video setup. So one battery is used for everything. I used to have a dedicated 3S Lipo feeding the video Tx (It won't take 2S as far as I know) but removed that to save weight and that setup worked for me at close range, so I never noticed any issues.

Are you saying you have to use a dedicated battery and whatnot? The voltage fluctuations in the main power train is enough to throw off the 5.8ghz equipment? I've heard the thing about some cameras being noisy, mine's right up against the video Tx, here's a pic of the setup, ignore the antenna, I've got yours on it right now. Also, I'm using the Hobbyking 200mw 5.8ghz kit.

Just a thought but are those props the ones that have carbon in them? If so maybe they could be blocking the RF to the ground?
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Old Apr 08, 2012, 04:30 AM
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Don't know, but they're probably CF reinforced or something. I know the props I have now are CF reinforced. (9x4.7 Gemfans) I'll post a pic of my current setup before I head out.
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Old Apr 08, 2012, 05:57 AM
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Quote:
Originally Posted by WiseDuck View Post
Don't know, but they're probably CF reinforced or something. I know the props I have now are CF reinforced. (9x4.7 Gemfans) I'll post a pic of my current setup before I head out.
Before we forget, may I ask how your ground station looks like? Limitted range can also have it's source on this end of the link.

Markus
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Old Apr 08, 2012, 08:53 AM
Mmmmmmm!
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Kingdom of Sweden, Dalarna County, Sater
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Quote:
Originally Posted by markus123456 View Post
Before we forget, may I ask how your ground station looks like? Limitted range can also have it's source on this end of the link.

Markus
I wouldn't call it a station yet, but I've got an LCD screen on the way which will fit into that compartment in the lid. Anyhow, this is what I usually set up. Always on a bench or something so I sit below the antenna.

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Old Apr 08, 2012, 09:17 AM
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Originally Posted by WiseDuck View Post
I wouldn't call it a station yet, but I've got an LCD screen on the way which will fit into that compartment in the lid. Anyhow, this is what I usually set up. Always on a bench or something so I sit below the antenna.
Nice box. :-)

From a HF standpoint of view it would be better to have that antenna on a tripod, 3m above ground, but that would make a difference of say flying out 2km versus 4km. So from looking at your groundstation I don't think the problem is there.

Ok, focus on your copter. As you said, you had better range with the tx battery cam and antenna alone so we agree it's one of the other onboard components. I would also check for a blocked LOS.

Markus
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Old Apr 09, 2012, 10:51 AM
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Okay guys,
I think I found my center of noise. And I think that should have been much earlier in my mind.

My FPV System is running from a second battery. Everytime I was going for some range there were interferences and lines moving through my picture. After some time I recognized that it relates to the throttle. The higher the throttle the higher the interferences. The noise has to come from my plane and not from the FPV system. Today I was looking at my plane and recognized that the ESC is mounted in the fuselage and not outside. The cables between motor and esc were about 50cm (20inch) long.

Am I right when I say that long cables between ESC and motor CAN produce big noise ?

Today I placed the ESC on top of the fuselage and cutted the cables to a size of 10cm. Cause of rain I am not able to test it but I am pretty sure that this relates to my problems.

Can anyone confirm my guess with the cables ?
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Old Apr 09, 2012, 11:13 AM
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Quote:
Originally Posted by Airbuzzler View Post
Okay guys,
I think I found my center of noise. And I think that should have been much earlier in my mind.

My FPV System is running from a second battery. Everytime I was going for some range there were interferences and lines moving through my picture. After some time I recognized that it relates to the throttle. The higher the throttle the higher the interferences. The noise has to come from my plane and not from the FPV system. Today I was looking at my plane and recognized that the ESC is mounted in the fuselage and not outside. The cables between motor and esc were about 50cm (20inch) long.

Am I right when I say that long cables between ESC and motor CAN produce big noise ?

Today I placed the ESC on top of the fuselage and cutted the cables to a size of 10cm. Cause of rain I am not able to test it but I am pretty sure that this relates to my problems.

Can anyone confirm my guess with the cables ?
This can be yes, a range test once weather clears up will give you the answer. Please let us know the outcome.

I wonder though, do you use a common GND between the power system and the video system? If so this would leave the door open for noise from the ESC propagateing into the tv system. Note, you may HAVE to have a common ground or virtually would have a hard time to get around it, i.e. when using an OSD with a current sensor etc. Your best bet then would be to filter the ESC side similarly like if you would use only one battery.

Markus
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Old Apr 09, 2012, 11:27 AM
Kiwi in Germany
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Germany
Joined Jun 2010
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Markus since you seems to know much more than a hack like me, what would be the smartest way to get to 3.3volts from s4 to s2 batteries?

Each regulator I look at has a frequency reading. Does that matter to me and if so what should I be looking for? I have seen them range from about 200khz - 2000khz.

While I wanted to use a linear reg I have noticed I am not able to at these voltages. Is it better to get a switching reg from 16 volts down to 3.3v or is it smarter to look for a switching reg that goes to 5volt and then use a linear reg?
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Old Apr 09, 2012, 12:37 PM
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Hello Markus,
thank you for you answer. I will test it soon and will let you know how it went up.

You are talking about a LC Filter ? I dont know much about all this stuff. Is it something like this ? http://www.rcgroups.com/forums/showp...7&postcount=14
Are there any other tutorials in the web how to build such a filter ?
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Old Apr 09, 2012, 12:53 PM
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Romania, Dolj, Craiova
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Quote:
Originally Posted by Airbuzzler View Post
...Today I was looking at my plane and recognized that the ESC is mounted in the fuselage and not outside. The cables between motor and esc were about 50cm (20inch) long.

Am I right when I say that long cables between ESC and motor CAN produce big noise ?

Today I placed the ESC on top of the fuselage and cutted the cables to a size of 10cm. Cause of rain I am not able to test it but I am pretty sure that this relates to my problems.

Can anyone confirm my guess with the cables ?
When you need to extend cables between pack - ESC - motor, is better to extend esc to motor cables, not pack to ESC cables.
The noise supposedly due to longer ESC to motor cables, could be due to a low quality ESC too, or can be greatly reduced by twisting them. Think to multirotors , they have 3-8 arms, each with 40cm of wires and no interferences.
Longer cables between pack and esc, more tha 10", could led to ESC damage in time, there is a dedicated thread explaining this in more detail and why.
Major ESC manufacturers specify this fact in their ESC booklets.
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