127 replies to this topic

[BlueAngel]

I had the same problem with the AWM633 2,4GHZ 450mW module with a Recom 3,3V switching reg.
to close to the module => lines in the video
I needed a LC-Filter too, because of the noise of the regulator.

I don't know if i should buy this Airwave 450mW 5,8GHz module, because i have the Sky-RF 200mW 5,8GHz Sets and they work very good, even with the 3dbi whips.
I have done the review here:
http://fpv-community...-5g8-200mw-fpv/

Would be nice if someone could compare these both systems, so i don't have to buy another module.

[Terry]

If I were you I would stick with the 200mW system as you seem to have good results from it, any improvement is going to be small. I always choose to fly with the minimum safe power for the job and 9 times out of 10 my 100mW TX is more than enough.

Terry

[BlueAngel]

thanks.

Okay, i will stay with the Sky-RF modules.
They are not getting that hot and cheap too.


Normally i fly 10mW 2,4GHz and it works really good.
1600m with 11dbi diversity patch with good video.
16dbi & 18dbi Yagi is already in the house.

[Cyb]

Hi,
Just one question : Does some 2.4ghz radio can interfere with 5.8ghz video ?
When I'm flying alone at my club, everything's OK, image is good, range too. When other pilots are flying at the same time as me, I got whites lines on the screen and image looks bad even at < 100 meter range.
They have branded radio like Spektrum and Futaba so the RF range is well defined and should not interfere with 5.8ghz video right ? I myself am flying with a Futaba and a Spektrum and I hadn't these whites lines...
Any reason to explain this ?

[Terry]

Its very unlikely that you would get interference unless the 2.4Ghz TX is very close to the 5.8Ghz RX. I fly on 2.4 rc and 5.8 video with other around sometimes on 2.4 and have not seen a problem. Do you use a patch type aerial on your 5.8 RX, this should reduce the problem as long as the 2.4 rc TX is not infront of the patch. I think it more likely that its not 2.4 interference that is the problem, you will have to do some testing to isolate the cause


Terry

[Cyb]

Hi Terry,
No I don't have any patch antenna. The strange thing is that it works until someone else turns on its radio (... or this is what I think but it is maybe not related...).I'll make some more tests then although I don't really know what to try !

[Mr.RC-Cam]

I've seen interference on a 5.8GHz A/V receiver from a 2.4GHz R/C Tx that was too close. But moving the 5.8GHz rx further away and to another channel has always cured that problem.

[Starjet]

I have the same issue with the immersion 600mw vtx on 3 cell lipo,it's driving me nuts as I switched from1.2ghz which had no issues. I have simply connected the cam wires as required with a positive jumper fom the battery (12v) i was using the negative supply from the vtx and suspected the interferance was from there but running a direct negative from the battery made no difference.
Any help would be appreciated.

[Terry]

Just out of interest did anyone come up with a fix for the herringbone patern problem?
One of mine has it quite bad


Terry

[Mr.RC-Cam]

Are you using a 2S LiPO, or is it 3S?

[Devonian]

Terry, I never did resolve mine (with 3S battery).
Tried all the suggestions Mr RC-Cam gave but to no avail.
I even tried a bit of shielding between the 2 boards, still no improvement.
Only other way was to dismantle the 2 boards and run the VTx section from a 5v BEC - cured the herringbone, but wasn't what I was after.
Running from a 2S works (and cures it), but then the camera doesn't, unless I power it seperately at 3S

I also have another well know/respected VTx, 2.4GHz @ 500mW and it too has very similar herringbone characteristics !

Watching with interest...

Nigel.

[Terry]

3s, if you remember I had a cutting out problem when using 2s. The odd thing is that it is hardly noticeable on 2 out of 3 units. Also remember I am powering the KX131 camera from it.

Would powering it from 4s work? or some other voltage? or maybe use an external bec?


Terry

[Mr.RC-Cam]

3s, if you remember I had a cutting out problem when using 2s.

I was going to suggest that if using 3S, a downsize to 2S (supply voltage <8VDC) would probably eliminate the problem.

The odd thing is that it is hardly noticeable on 2 out of 3 units.

From the feedback it seems the problem is not seen on all boards. But unfortunately a simple fix has been elusive.

Would powering it from 4s work? or some other voltage? or maybe use an external bec?

An external BEC will fix the problem. You won't need the Tx's DC-DC power supply board if you use a BEC.

In case it is practical for you, increasing the distance between the two stacked boards (at least an inch or so) seems to fix it too. Or skip the stacking trickery and wire them separately. The goal is to get the DC-DC's magnetics away from the Airwave RF module.

[Terry]

ok thanks will have a play when I have time


Terry

[Devonian]

OK, I got some time to play at the workbench and decided to try and fix my 'Herringbone lines' problem.

Mr RC-Cam had suggested that he never saw the problem with his test rig - which the 2 halves of the board are seperated by quite some distance.

So, I cut all the joining jumpers between the 2 halves of the board, soldered in longer ones by 9mm (3/8") and tested it with 3S LiPo.
No herringbone lines!

So, kept moving the boards together by 3mm (1/8") at a time and re-test.
I got to about 3mm further apart than normal and just started to see some lines (very minimal).

I ended up staying at 3mm as it was quite acceptable and once the LiPo voltage went down a little, the lines were gone. I added 2 little slices of copper clad PCB between the can of the module and the underside of the board (in an 'L' shape) and tinned them into place, this stops the 2 boards from 'rocking about' with the slightly longer jumper wires/legs.

Pics to show the end result.





Nigel.

[Terry]

WOW Nigel this is so well timed !!!
I had the problem with one of my units and have had the boards split sitting on my bench for about 2 months intending to do what you have done. Only this morning I dug out the wire to join the boards up again but got side tracked as usual and didnt do it.

I have been wondering wether to convert to a linear reg to be sure of sorting the problem but now I feel happy to try what you have done. Many thanks for the info

Also good to see you are still active in the hobby, I have done very little this year but have hopes for next. We must meet up again some time


Terry

[Kilrah]

have had the boards split sitting on my bench for about 2 months intending to do what you have done. Only this morning I dug out the wire to join the boards up again but got side tracked as usual and didnt do it.
[...]
I have done very little this year but have hopes for next.

Totally O/T, but thanks for the "Cool, I'm not the only one" moment

I've done ridiculously little this year. I actually just "started the season" last week by repairing some planes from last year and receiving 3 new ones... right when it's ended.

[Mr.RC-Cam]

I ended up staying at 3mm as it was quite acceptable and once the LiPo voltage went down a little, the lines were gone. I added 2 little slices of copper clad PCB between the can of the module and the underside of the board (in an 'L' shape) and tinned them into place, this stops the 2 boards from 'rocking about' with the slightly longer jumper wires/legs.

Thanks for posting your mod. It's a very annoying issue but it's nice that the solution is not a horrible ordeal.

- Thomas

[Terry]

Well thanks back Kilrah, it is indeed good to share

Well I have reduced the patterning problem by 90% by sliding the boards apart and not making the whole think thicker. I also had to add an extra capacitor to the 5v side as I use that to power my KX131.

All seems ok but not flight tested yet!


Terry

Attached Thumbnails

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Edited by Terry, 19 December 2011 - 06:22 AM.

[Mr.RC-Cam]

Well I have reduced the patterning problem by 90% by sliding the boards apart and not making the whole think thicker.

That's a unique way to do it.