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Old Nov 28, 2012, 04:48 AM
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Originally Posted by markus123456 View Post
David,

I asume you used a real video transmitter with it's propper voltage regulation section. The original poster uses a pure HF module. Noise coming from the ESC throught the power lines is not the same as inducted noise. The problem with the ESC is that the high pulses of current consumption that the motor draws lets the level of the both the output voltage (plus signal) AND signal ground vary. A simple LC filter cannot get rid of this part of the noise as it's input is also subject to the changeing gnd level and if you consider that the video signal only has a very small voltage swing (0.3 - 1.2 volts usually), a change of the ground level will change the relative voltage of that signal hence the colour information as the video tx sees it. This subsequently introudces the visible lines in the picture. Filitering this out propperly is of course doable. A real tx does exactly this in it's power regulation cirquitry. However, doing this requieres some bigger capacitors for the lc filter and also some aditionional steps behind that stage. In the context of a very small plane (as the original poster seems to use), that sum of weight and complexity may means that using a dedicated lipo is just the simpler aproach. If he has enough power to have more weight on board, he simply could buy the full flegged transmitter and be done instead of trying to turn his HF module into a full flegged transmitter. The main differnece between his module and a real transmitter IS in fact the power regulation....

Markus
In that video as example I use fox 800 which has no regulator in it.

When battery gets low like near 9 volts I can see lines or colr changes in video due low volts

This tells me when to,land

So there is no power regulation

I have to stress the positioning of wires and video tx near conductive materials and also haveing wires close or crossing each other
I fly high performance gliders which have carbon in them and install of video systems can be tricky due to lines because of carbon
I had real problem with lines and simply solved it by slightly rearranging the wires and video tx away from the carbon spar
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Old Nov 28, 2012, 05:02 AM
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Quote:
Originally Posted by David22 View Post
In that video as example I use fox 800 which has no regulator in it.
No offense David, but if that tx runs off batteries as you say, it very very likely will have a regulator inside. Do you have a link to the very product you were using, as Fox - 800 returns multiple products in the 900 Mhz and 1.2Ghz bands.

Markus

[Edit] I also do NOT doubth that HF interferance or other problems might be solved by rearangeing components. However the cathegory of noise the OP talks about falls into a different league where rearangeing definately will NOT help[/Edit]
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Old Nov 28, 2012, 05:09 AM
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Originally Posted by markus123456 View Post
No offense David, but if that tx runs off batteries as you say, it very very likely will have a regulator inside. Do you have a link to the very product you were using, as Fox - 800 returns multiple products in the 900 Mhz and 1.2Ghz bands.

Markus

[Edit] I also do NOT doubth that HF interferance or other problems might be solved by rearangeing components. However the cathegory of noise the OP talks about falls into a different league where rearangeing definately will NOT help[/Edit]

I never get offended I am strong guy hehehe

Long ago I send Thomas two video tx units

One was fox 1 watt video tx, so I assume 800 is same with no regulator

Other was lawmate 1 watt video tx

Both he did extensive testing on

But here is info about the fox tx and specs
And lawmate
If you look at his specs for lawmate it has regulator

Interesting info

http://www.webx.dk/rc/video-wireless/1240_1W.htm

http://www.webx.dk/rc/video-wireless/2400_1W.htm
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Old Nov 28, 2012, 05:18 AM
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Quote:
Originally Posted by David22 View Post
I never get offended I am strong guy hehehe

Long ago I send Thomas two video tx units

One was fox 1 watt video tx, so I assume 800 is same with no regulator

Other was lawmate 1 watt video tx

Both he did extensive testing on

But here is info about the fox tx and specs
And lawmate
If you look at his specs for lawmate it has regulator

Interesting info

http://www.webx.dk/rc/video-wireless/1240_1W.htm

http://www.webx.dk/rc/video-wireless/2400_1W.htm
It's pretty obviouse that those tx do have a voltage control as most of the chips used inside will require a standard voltage like 5volts or 3.3volts and so on. The higher input voltage might (but not necesairly) be used in the final power amplifyer stage, but the part of the tx doing the modulation of the video signal (which is prone to what I described before) is almost certainly not running on the input voltage level.

HTH

Markus
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Old Nov 28, 2012, 05:21 AM
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Originally Posted by markus123456 View Post

[Edit] I also do NOT doubth that HF interferance or other problems might be solved by rearangeing components. However the cathegory of noise the OP talks about falls into a different league where rearangeing definately will NOT help[/Edit]
One trick I use in fpv and to get best results is to try to make things worse
By as example putting carbon rods near my video,system

This way you can eliminate what is causing your noise or rc reception

If you suspect lines are caused from vibrations but not sure try unbalanced prop to see if video gets even worse, if so then really try hard to,balance prop or eliminate vibrations to video system

If you think esc is causing noise, put video wires closer toe esc wires and cross them on purpose to,make video as,worse you can to see what is real problem

Or if by chance you mounted video system on carbon frame of copter and might think this is problem take off video system and run the copter or plane with video system off of plane and way from carbon

Purposely marketing things worse or trying to helps lots to find your problems

Of course this tests are done on the work bench
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Old Nov 28, 2012, 05:27 AM
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Quote:
Originally Posted by markus123456 View Post
It's pretty obviouse that those tx do have a voltage control as most of the chips used inside will require a standard voltage like 5volts or 3.3volts and so on. The higher input voltage might (but not necesairly) be used in the final power amplifyer stage, but the part of the tx doing the modulation of the video signal (which is prone to what I described before) is almost certainly not running on the input voltage level.

HTH

Markus
You can see in specs that lawmate only needs 10 volts to,operate efficiently

Anything more is just waste of energy

Fox however works best at 12 volts and decreases in power out put as volts go,down

So I see no regulator in the fox but in lawmate I do

Yes both are designed for 12 volt operation

Maybe lowering voltage input will clear up video in some cases
With certain video Txs or cameras

Or in the case as you discuss
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Old Nov 28, 2012, 12:12 PM
OSUFPV - KF7VFT
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Originally Posted by markus123456 View Post
By far not all noise is canceled out by a simple LC filter. Besides, if you want a really good one, you need to have a C with a bigger capacity whoes weight quickly starts to "outweight" the weight of a small single lipo cell. It's a tradeoff and which aproach is better depends on the application.

Markus
I never said all noise would be cancelled out, but it should be enough to cancel
out all visible noise in the video. The necessary capacity and inductance of the
LC filter to reduce noise scales with the magnitude of the current. Since he's using
very small batteries with low currents the inductive and capacitive values
needed for the filter will also be small.

-Blues
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Old Nov 28, 2012, 01:32 PM
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Altough my first experience in fpv was bad, I want to do interior fpv for training.

Do you know where I can found 1gr cam and 10mW 5.8ghz tx
I found it at fpvhobby but it is out of stock...
I am looking for cheap equippement (china) as it is for training
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Old Nov 28, 2012, 01:36 PM
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Originally Posted by Blueshy View Post
I never said all noise would be cancelled out, but it should be enough to cancel
out all visible noise in the video. The necessary capacity and inductance of the
LC filter to reduce noise scales with the magnitude of the current. Since he's using
very small batteries with low currents the inductive and capacitive values
needed for the filter will also be small.

-Blues
Ok, if we are about splitting hairs, , I also said that an LC filter is worth a try.

See, many people will read this thread, especially beginners, and my intention is to make clear that an LC filter not necessairly solves this particular problem in all cases. Maybe it would for the OP, maybe not. It's worth a try of course, but going for a second smallish lipo will solve the problem to 100%. Thats my point, and no I did not tried to educate you or turn your answer down. Really not, I just wanted to give enough information for others with the same type of issue so as they get a better understanding of what's going on.

Markus
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Old Nov 28, 2012, 03:12 PM
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You're right Markus, except one thing; a second lipo is one more thing to worry about while an LC filter is worry-free.

flight-battery...check
transmitter-battery...check
goggles...check
vrx supply...check
recorder-battery...check
=> go flying ... oops forgot to check vtx-battery

Not saying that a one-lipo plane is always better though, but I guess it's at least a bit easier.

Martin
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Old Nov 28, 2012, 03:38 PM
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I use a separate lipo for my video gear and I also have a LC filter on board.... the picture is very good.
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Old Nov 28, 2012, 03:45 PM
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Originally Posted by Martin. View Post
You're right Markus, except one thing; a second lipo is one more thing to worry about while an LC filter is worry-free.

[snip]

Martin
Yes, verry true. In genereal I also use one battery setups especially as I can help myself with building a good enough filter. For those who don't have this option and asuming a micro fpv setup, the second battery is a valid option, albeit not the only one :-)

Markus
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Old Nov 28, 2012, 04:36 PM
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Originally Posted by Martin. View Post
You're right Markus, except one thing; a second lipo is one more thing to worry about while an LC filter is worry-free.

flight-battery...check
transmitter-battery...check
goggles...check
vrx supply...check
recorder-battery...check
=> go flying ... oops forgot to check vtx-battery

Not saying that a one-lipo plane is always better though, but I guess it's at least a bit easier.

Martin
One battery is easier all around
Very convient and makes things easier
It great to have just one to charge while driving to go fpv
Only one also faster to get into the air,
two three even five battery set ups take that much longer
Using just one battery in the plane, not two for main battery in parallel
But just one in plane and on ground station

But for set ups and flights for long range or long flight time, I install separate batteries for video that lasts for about 2 hours or more depending on expected flight time with margin, rx batteries are also dependant plane and flight . Main battery choice dependant on flight and even add two main batteries for long flight

There is no wrong or right way to set up a plane Beit one battery or like five on a plane

Good thing about separate batteries is that main motor battery can be used up completely if needed or wanted, I drain main battery many times so motor does not work anymore
To edge of voltage curve before it drops off fast
Separate batteries let me glide around much longer than just one battery set ups

This is why most of my planes have multi[ple batteries
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Last edited by David22; Nov 28, 2012 at 04:41 PM.
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Old Nov 28, 2012, 04:49 PM
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hey guys,

I want to mount my Video RX on a long pole. I'm flying on 1280mhz and am wondering if it matters if my pole is metal, wood, etc...??
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Old Nov 28, 2012, 05:28 PM
OSUFPV - KF7VFT
Corvallis, OR
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Quote:
Originally Posted by markus123456 View Post
Ok, if we are about splitting hairs, , I also said that an LC filter is worth a try.

See, many people will read this thread, especially beginners, and my intention is to make clear that an LC filter not necessairly solves this particular problem in all cases. Maybe it would for the OP, maybe not. It's worth a try of course, but going for a second smallish lipo will solve the problem to 100%. Thats my point, and no I did not tried to educate you or turn your answer down. Really not, I just wanted to give enough information for others with the same type of issue so as they get a better understanding of what's going on.

Markus
Sure, you did say the LC filter was worth a try. The difference is that I never
said that you said it wasn't.

I was only answering the OP's question. Not trying to provide a general
answer to all problems related. If anyone thinks that they could just tune
into this thread with a similar problem and find an exact solution they are
mistaken. This thread serves on an individual answer basis and it would be
stupid to assume that a previous answer is correct for all similar cases.

-Blues
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