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Old Mar 12, 2012, 12:58 PM
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Cool, thank you!
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Old Mar 12, 2012, 02:07 PM
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Quote:
Originally Posted by nkkromhof View Post
Slightly off-topic, but this thread seems to be as good a place to ask as any:

When using a 5.8Ghz CP omni antenna, how high do you recommend raising the RX/antenna from the ground.
I'm sure "as high as possible" will be a popular answer, but I'm looking to balance practicality with maximizing range on the omni and I'm guessing there's a point of diminishing returns.
I'm using a tripod with a wooden stick mounted onto it and the rx is then on the top of that stick. Sits about 3m above ground this way. This makes sense as otherwise people walking around you will get into the LOS with potentially disasterous consequences. I'm flying with glasses, and often don't have control over who is aproaching me and again this height above ground solves this problem.

From a link standpoint of view probably 2m or even slightly less should be sufficient.

Markus
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Old Mar 12, 2012, 03:52 PM
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While I'm waiting for the video rx to arrive I'm slowly trying to look at the schematic and have a few questions.

Do I need those 470uF caps? Do I need to connect all the ground pins (3,5,11,9) to ground or just one?

Can the module tin case be considered as ground for channel selection? Ground for power should be the ground on power supply and should be connected to one of the pins - 3,5,11,9 right?

Can the tin case also be considered as ground for antenna? The coax central conductor should be connected to pin 10, should the outer shield be connected to tin case?
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Old Mar 12, 2012, 04:23 PM
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Quote:
Originally Posted by msev View Post
While I'm waiting for the video rx to arrive I'm slowly trying to look at the schematic and have a few questions.

Do I need those 470uF caps? Do I need to connect all the ground pins (3,5,11,9) to ground or just one?

Can the module tin case be considered as ground for channel selection? Ground for power should be the ground on power supply and should be connected to one of the pins - 3,5,11,9 right?

Can the tin case also be considered as ground for antenna? The coax central conductor should be connected to pin 10, should the outer shield be connected to tin case?
The caps are not needed if you have a very clean power source (dedicated battery). GND is connected internally, so answer is no. The case is GND too, so yes you can use it for strapping the channel. Again, GND is GND, does not matter where you connect it. The antenna should be connected such that the center of the coax goes to the decicated pin AND THE MESH SHOULD BE CONNECTED TO THE TWO PINS ON THE SIDES OF THIS CENTER PIN. That's very important for shielding purposes and to maintain the impedance of the output.

HTH

Markus
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Old Mar 12, 2012, 05:13 PM
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Thanks M.! So shielding should be connected to both pin 11 and pin 9...Great!
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Old Mar 12, 2012, 05:18 PM
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Originally Posted by msev View Post
Thanks M.! So shielding should be connected to both pin 11 and pin 9...Great!
Yes, and the shorter/closer you manage to do this the better.

Markus
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Old Mar 12, 2012, 05:41 PM
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Originally Posted by edge0xc View Post
hey,
i just got my 200mW TX, but it looks like, if there is something missing?
Is this normal?
Cheers
Alex
hi Alex,
i received my set from foxtech today. the cap is also not soldered on my tx!
seems to be the new lo-cost version
can anyone translate what "476 25K 011" means .... xxF/yyV?

cheers Thomas
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Old Mar 12, 2012, 05:49 PM
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Originally Posted by Thint1 View Post
hi Alex,
i received my set from foxtech today. the cap is also not soldered on my tx!
seems to be the new lo-cost version
can anyone translate what "476 25K 011" means .... xxF/yyV?

cheers Thomas
It's a relatively expensive low ESR capacitor and I suspected the factory started to make them without it. The transmitter will work as the output stage of the dc/dc converter is likely to have capacitors too. Maybe those transmitters have more noise in the picture or are a bit more prone to noise but we would have to measure and compare them to know.

Markus
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Old Mar 12, 2012, 11:53 PM
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Originally Posted by Thint1 View Post
hi Alex,
can anyone translate what "476 25K 011" means .... xxF/yyV?

cheers Thomas
It's a tantalum 47F capacitor and it is not so expensive, 0.10-0.20 USD. Or maybe it is expensive for the Chinese cheap manufacturers
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Old Mar 13, 2012, 03:45 AM
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Are my Yagis the ugliest?
I get lightbulb lit within 20cm using AWM 500mw TX

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Old Mar 13, 2012, 04:21 AM
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Originally Posted by futurebreeze View Post
It's a tantalum 47F capacitor and it is not so expensive, 0.10-0.20 USD. Or maybe it is expensive for the Chinese cheap manufacturers
Please let me know where you get these LOW ESR tantalum capacitors for this price. I did a little search on Mouser.com - surely not the cheapest supplier, but also not that bad.

http://ch.mouser.com/Search/Refine.a...uF&NewSearch=1

There are variants, especially the LOW ESR ones which even cost > $5 per piece.

Seriousely, if you have a quality supplier with that cheap prices - please foreward it.

Markus
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Old Mar 13, 2012, 04:29 AM
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fmkit - 2 element Yagi - but now you are back to linear mode.
Try a crossed Yagi and phase feed for C-P...

Yes, the ugliest on RCG

Nigel.
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Old Mar 13, 2012, 05:28 AM
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Quote:
Originally Posted by markus123456 View Post
Seriousely, if you have a quality supplier with that cheap prices - please foreward it.

Markus
I don't know if they are really low ESR but these capacitors are better than nothing on that PCB
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Old Mar 13, 2012, 05:38 AM
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Originally Posted by futurebreeze View Post
I don't know if they are really low ESR but these capacitors are better than nothing on that PCB
They seem to be pretty much ok to me. Thanks for this link. I so far had to spend a fortune on those suckers.

Markus
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Old Mar 13, 2012, 08:51 AM
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Originally Posted by markus123456 View Post
They seem to be pretty much ok to me. Thanks for this link. I so far had to spend a fortune on those suckers.

Markus
hi futurebreeze, Markus
as i would like to have the best filtering possible i searched a little bit for the capacitors.
the european distributors are a little bit crazy ... shipment costs up to 20,-- EUR
finally i bought on ebay .... 10 pcs for 2,99 pound and 1pound shipment.
http://www.ebay.co.uk/itm/1108311289...84.m1497.l2649

cheers Thomas
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