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AndrejSl

2.4GHz 200mW system suspected Receiver problem

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Hello everyone!

I have this wireless video system for about a year now, the range is very short (picture starts fading at 220m).

But only recently i have discovered what i think is the problem, the antenna of the receiver is in complete short circuit with the ground and it's factory made that way!

I found a very tiny about half a milimeter wide and 1cm long connection between the antenna and ground on the circuit....

This is not right is it ?

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Need some clarification: Is the "short" on the antenna or the input to the receiver? If its on the antenna then post a photo.

Keep in mind that DC (ohmmeter) shorts are not shorts to the RF. On the other hand, some ohmmeter "opens" are direct shorts in the RF world. And, those odd little circuit board traces are used as inductors. RF is very different from DC and can be confusing. :)

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the short circuit is in the receiver.

Ok i guess it's meant to be that way but it just didn't make sense to me how can ground be in direct contact with antenna.

This high frequency RF stuff is very strange and confusing...

But what else could be the reason for such bad performance... I read on this forum some got 300 or more meters of range with 10mW.

Which means this 200mW should be at a very minimum twice as that with stock antenna and everything...

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This high frequency RF stuff is very strange and confusing...

RF circuits are not as intuitive as DC circuits. Like Dorothy said to Toto, "I've a feeling we're not in Kansas any more."

Range is highly dependent on the equipment, environment, and installation. And if you ask me, Rx performance is as important as RF Tx power (perhaps more so). So, comparing a 10mW Tx that gets 300m, to your 200mW that gets only 200m, usually does not really mean much.

Your system could be just fine given your particular situation. And just about any low cost package can be improved a bit. For example, if you are using a simple whip on the Rx then upgrade to a patch antenna. You can build one for $10. If the Tx has a simple monopole whip, then change to a good 2-3dBi gain dipole. If the antennas are not both vertical, then reposition them. The list goes on and on.

Also, it's very hard to make any useful comments without watching a video recording that demonstrates your issues. It's all guesswork otherwise.

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Thanks for explanation, i understand what you mean...

Anyway i'm looking for a new system already but i can't decide which one of these would be better for me:

Combo Set Receiver +Transmitter 1.2Ghz 1000mW

Combo Set Receiver +Transmitter 900Mhz 500mW

I'm afraid that 1000mW may seriously start to interfere with airplane's or (helis) receiver at long range even if it's tuned to 40MHz, because there is little space to put them far enough apart, you think that could happen ?

Also can you tell me what would be the effective ranges of those systems, and of 40MHz RC ?

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