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What causes this guys?

I'm talking about the diagonal lines in the video, sometimes more or less, see captured screen shots.

a1.jpg

a2.jpg

Thanks in advance,

Gert.

Edited by viper1

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Causes can include a long host of sources, mostly related to the installation. It would help if you provided all the details to your airborne and ground station. For example, what exactly is installed, how is it powered, etc.? Photos of the bits might be helpful too.

If your power supply includes a DC-DC switcher Vreg, or even a simple linear Vreg with inadequate decoupling caps, then I would investigate them first.

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Guilty:, Installation was the worst possible (no plane ready, taped onto my mates trainer)

Fact is that last night I checked at home and lines are there while holding the system in my hands (or laying on table)

Here goes for the details:

bwav (lawmate?) 200mw tx (5V) on 4 nimh cells directly,

Cam is 12V, powered by same battery via PT5041 ISR with correctly (according to datasheet) installed caps.

The whole lot (TX and Reg) installed in the same housing, yep, a recycled battery housing , only survivor from my sony photo camera crash ;)

Such a compact fit, I couldn't resist but it could be too close to each other...

Ground station = bwav rx with 8Dbi patch

15.jpg

16.jpg

17.jpg

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Update;

In the process of eliminating problems,

Connected the camera straight to TV,

result: sharp & 100% picture.

I would be wrapped if I can get a slightly better picture, it does look good with this hi-res cam (620 lines)

Then I used the wireless TX & RX I got at home (different, low power version used for transmitting audio/vid to the bedroom)

result: the lines/noise do appear, although not as obvious as with the aerial system.

Thusfar I suspect the power supply, more specificly the switching regulator..

I'll try to describe the noise better; It looks like the lines are bouncing, or moving up -and down slowly, switching direction approx. every 4 secs

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Thus far I suspect the power supply, more specifically the switching regulator..

Yup, if there is a DC-DC switching Vreg in there then it is probably the cause. They take extra care to avoid those video artifacts. I recommend very short wire leads, very low ESR decoupling caps, perhaps some type 43/77 ferrite beads in the right places, and a bit of luck.

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When you connected the camera stright to tv, did you power it with the 4.5v-12v power supply? That would test the power supply without the added confusion of the tx/rx.

Why not go with a 3 cell li poly pack, run the camera directly, and use a std voltage reg to drop you to 5v for the tx? I have used an old burned out esc before, which still had the bec intact, at 200mw, I don't think the heat would be too bad, and you would still be about the same weight as 4 nimh cells

a little off topic, but what camera are you using?, I haven't seen a small 620 line color camera before

Ken

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Yup, if there is a DC-DC switching Vreg in there then it is probably the cause. They take extra care to avoid those video artifacts. I recommend very short wire leads, very low ESR decoupling caps, perhaps some type 43/77 ferrite beads in the right places, and a bit of luck

HELP!!!! :o:o

Only caps I added are the ones on the datasheet:

caps.jpg

what is low ESR ?

And where would "the right place" for the ferrite beads be?

Apologies, but I wouldn't consider myself an "electronic wonder" :blink:

All that's left is you guys, or: "A bit of luck"

When you connected the camera stright to tv, did you power it with the 4.5v-12v power supply? That would test the power supply without the added confusion of the tx/rx.

Yep, powered it both ways, supply reg & 11.1 lipo

also with & without wireless

Why not go with a 3 cell li poly pack, run the camera directly, and use a std voltage reg to drop you to 5v for the tx? I have used an old burned out esc before, which still had the bec intact, at 200mw, I don't think the heat would be too bad, and you would still be about the same weight as 4 nimh cells

If there is no other way I will have to do that, reason I went for this setup is

because I want to swap on as many planes as possible: light & heavy, and nimh's give me more flexibility as I already have many cells in different capacities & size.

(And I got 'm very cheap)

a little off topic, but what camera are you using?, I haven't seen a small 620 line color camera before

"Small" is a relative, as this is a 1/3 ccd, a bit bigger than the 1/4" chip boards

I got this camera: LINK

Only drawback is the bullet & bomb-proof steel casting housing, so I vac-formed my own ABS case, and reduced the weight from 75 grams to 22 (translated: 2.65oz to 0.7oz)

Also reduced the size a little bit.

Now the complete system -ex battery- weights less than the cam only original

piccy:

cam.jpg

Edited by viper1

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what is low ESR ?

ESR = Effective Series Resistance. It is an important cap specification. The required caps are special for this DC-DC Switcher application and the run of the mill choices will not offer the performance you need.

BTW, what is the part number and value of the caps you installed? Are their leads REALLY short? SMT caps are best since they have no leads.

And where would "the right place" for the ferrite beads be?

Where-ever they help your cause. There is no one-location-cures-all answer.

Killing the EMI/RFI noise is a trial an error ordeal. It will require patience (lots of it). But, it can be done.

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Thanks Mr Cam,

I probably got the wrong caps

afaik it's a standard of the shelf elco 100uf

and two ceramic 1uf caps

Hope I can find the low ESR caps over here.

This place is nearby, but I don't know what to look /search for ?

:unsure: (begging look in my eyes.....) :unsure:

RS-Components

Thanks in advance,

Gert

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I suggest an experiment is in order. Temporarily power the BWAV Tx from a clean 5V power source while the PT5041 Vreg & camera is powered from another 5V source. The only connection between the two should be the video signal cable. Does this eliminate the noise?

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I had the same noise when I used a switch mode supply. I twisted 2 12" lenths of 0.56mm copper wire together then wound them on a small ferrite ring. I used this between the psu and the camera/tx with capacitors at each side, dont remember the value though, maybe 100uF. Works well, no more lines :)

Terry

Edited by Terry

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I suggest an experiment is in order. Temporarily power the BWAV Tx from a clean 5V power source while the PT5041 Vreg & camera is powered from another 5V source. The only connection between the two should be the video signal cable. Does this eliminate the noise?

It's 02.30 in the morning so yes, I will try that now

:D

standby....

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That says a lot. I believe the "noise" is from the Vreg's 500Khz input ripple that is riding on top of the raw Battery voltage. If so, it will be easier to cure than the other types of switcher interference sources.

Here are my revised recommendations:

(1) Install the largest choke you can in series with the battery lead feeding just the Tx. A large cap (perhaps 470uF or bigger) should be on the input to the Tx too. The Vreg's power should not share the Tx's side of the choke/cap filter.

(2) A ferrite ring (type 43 or 77) on the battery leads (several wraps) might be needed.

(3) The battery leads must be short and heavy gauge. If steps 1&2 do not solve it, you will need to upgrade the battery leads.

(4) A battery pack with very low impedance is recommended. Frankly, most small consumer NiMH packs might not offer the lowest impedance. If steps 1 -3 do not solve it, try a freshly recharged 600mAH NiCD R/C pack and see if it helps.

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Question in regards to step 1 :

That means I'm still using 2 battery packs?

Afraid I don't understand without drawing /sketch

Batteries are ok I guess, I used before my stab. power supply

Edited by viper1

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One good hearty battery.

At the battery connector, create two V+ paths: One will go to the Vreg's input. The other goes to choke/cap, which feeds the Tx input. Common ground, minimize all lead lengths.

The point is to provide some AC isolation between the "noisy" input of the Switching Vreg and the input of the Tx (which needs perfectly clean 5VDC). The filter (choke/cap) on the input to the Tx is used to accomplish this.

Replacing the switching Vreg with a linear Vreg would be another solution. Even with a decent heatsink, the linear Vreg would probably run quite warm with a 12V input. So, plan accordingly (provide airflow).

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Very frustrating to be this close, but this goes over my head,

I would have no idea what to buy, what a choke or filter looks like, & which specs I need to look for.

I will order a complete, properly filtered gizmo from dimension engineering I guess, and test my patience....

Thanks for your help and time, and apologies for my lack of knowledge

Last but not least, A very happy new year!

Edited by viper1

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I will order a complete, properly filtered gizmo from dimension engineering...

Please report how it works for you. Their Vreg's are switchers too -- If they don't fully solve the problem then keep the cap/choke idea in mind.

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I keep it constantly in mind, it just doesn't fall in place... :(

hmmm, 05.30AM, no wonder the grey substance stopped coƶperating.....

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First video posted, (temporary using 2 separate batteries)

http://media.putfile.com/pitts63

Scale cockpit view not ideal for watching the landscape but realistic I guess....

Still some interference, or static to get rid of but the camera shows it capabilities I think.....

.

Edited by viper1

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Looks really nice! You would have to put that cam on a servo to be able to look to the side between the wings, must certainly be very nice view :)

Anyways I should be receiving a little electric pitts soon, I'll have a try :P

Image is very good, but the RF transmission doesn't look very reliable to me... where is your TX antenna located?

And may I ask you when you've bought the camera? Because they have recently changed their CCD sensors from Panasonic ones to Sony ones, and I was hoping that the new ones would have less difficulty when they get the sun directly in the lens... but on there it seems to be the same.

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Hey, I just posted but it doesn't appear, only in the last 10 posts when trying to reply?!

Edit: Of course, now it does <_<

And I did try with another PC as well before...

Edited by Kilrah

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Image is very good, but the RF transmission doesn't look very reliable to me... where is your TX antenna located?

That's the problem when you play around with the video, again no time to get a plane ready in time, so I was limited to strapping it to someone else's plane.

The antenna was close to the cam, pointing up behind the pilot.

I used the patch on the RX side, while I was far away from suburbia, maybe I should have used the standard whip?

And may I ask you when you've bought the camera? Because they have recently changed their CCD sensors from Panasonic ones to Sony ones, and I was hoping that the new ones would have less difficulty when they get the sun directly in the lens... but on there it seems to be the same.

Bought it two weeks ago, yup, this one is with Sony sensor. Bought it here

I noticed before I ever flew the cam it's very high performance in very low light conditions, to be honest I already expected problems looking in direct sunlight.

After all it is designed for security purposes.

Maybe a color filter of some kind in front of the lens would make it a bit better?

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RX side is OK with the patch. But maybe putting the TX one under the plane would do better. I wonder if there couldn't be some reflections between the wings here :huh:

OK, so then I don't see any difference between the 2 camera versions. Of course all CCDs will have trouble with the sun, it's just the amount that changes between them. This one performs quite bad from my point of view, that is when flying FPV you'd better not face the sun too long or you have a complete white image.

Well that won't prevent me from using it though, detail is really awesome with adequate video goggles. It should get installed on a new plane pretty soon.

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I did a CSR ("cheap, simple and rough") -test today, as we noticed before, the camera has difficulty when it gets the sun directly in the lens

I taped an old pair of sunglasses directly in front of the lens and pointed it straight at the sun, what do you think?

Please ignore the weeds, too busy building planes B)

IMHO it fixes the "blackout" when facing the sun, but colors are less crispy with this 'filter'.

Your thoughts?

(Apologies for the quality vid, high compression and some "urban" interference....)

Comparison Video

I might cut out a piece of the sunnies and make a lens filter from it

Edited by viper1

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