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Old Jan 21, 2013, 03:30 PM
a little kid at heart
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Improve Tx antenna

I bought this toy quad a Syma X1. Really remarkable for the price of $35. I want to see if i can get a little more range out of it. Here is a pic (borrowed from craigiri ) of the antenna. Is their a solution here to get more range? Straighter antenna? True 1/4 wave length? (measured at 29.5) ??

Thanks

Bill
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Old Jan 22, 2013, 12:01 PM
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You can cut that PCB antenna right where it leaves the ground and solder on something else. Any antenna will probably do a little better than the PCB antenna. There's various reasons the best length may not be the theoretical length, you'll have to do some experimenting. There's lots on the net about different antennas you can try. I'd probably start with a piece of solid copper wire.
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Old Jan 22, 2013, 12:47 PM
Stuart
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Whats the frequency ?

A 1/4 wavelength might well be a measured 29.5, but 29.5 of what ?
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Old Jan 22, 2013, 03:26 PM
a little kid at heart
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Thanks for the idea on the antenna. It's ~29mm.

Thanks

Bill
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Old Jan 23, 2013, 03:47 AM
Stuart
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Frequency ?
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Old Jan 23, 2013, 04:02 PM
a little kid at heart
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Frequency ?
2.4ghz Beyond that how do you tell?
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Old Jan 24, 2013, 02:17 AM
Stuart
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Start with a bit of wire about 1 wavelength long, 12.5cm for 2.4Ghz and cut little bits off in stages to see if range is affected.

The classic length for a single wire would be 1/4 wavelength (3.2cm) but as mentioned previously you may well find that this is not the length for maximum output and thus range.
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Old Jan 24, 2013, 03:22 PM
a little kid at heart
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Quote:
Originally Posted by srnet View Post
Start with a bit of wire about 1 wavelength long, 12.5cm for 2.4Ghz and cut little bits off in stages to see if range is affected.

The classic length for a single wire would be 1/4 wavelength (3.2cm) but as mentioned previously you may well find that this is not the length for maximum output and thus range.
Thank you!!

Will give a try

One more thing...wire sideways or pointed straight up? Or perhaps the more correct question is...Try to keep the antenna pointed at the rx or perpendicular to it?

Thanks

Bill
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Old Jan 24, 2013, 04:04 PM
Stuart
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Transmit antenna in the same orientation as the receive antenna is normally best.

But then of course, why not experiment and see which way is best ?
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Old Jan 25, 2013, 11:13 AM
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Quote:
Originally Posted by poulsbobill View Post
One more thing...wire sideways or pointed straight up? Or perhaps the more correct question is...Try to keep the antenna pointed at the rx or perpendicular to it?
Never point a monopole or dipole antenna directly at the RX. The radiation pattern looks like a doughnut around the antenna. Pointing both antennas straight up is the easiest way to get the best reception.
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Old Jan 25, 2013, 09:48 PM
a little kid at heart
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Quote:
Originally Posted by srnet View Post
Start with a bit of wire about 1 wavelength long, 12.5cm for 2.4Ghz and cut little bits off in stages to see if range is affected.

The classic length for a single wire would be 1/4 wavelength (3.2cm) but as mentioned previously you may well find that this is not the length for maximum output and thus range.
Cut the trace here and solder on the new wire?

Thanks

Bill
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Old Jan 26, 2013, 01:18 AM
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Yep. The "antenna" begins right where the trace leaves the close proximity to the ground traces around it. I'd draw a line straight down from the end of the ground trace and cut there.
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