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#1 poulsbobill Jan 21, 2013 03:30 PM

Improve Tx antenna
 
1 Attachment(s)
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

#2 jakestew Jan 22, 2013 12:01 PM

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.

#3 srnet Jan 22, 2013 12:47 PM

Whats the frequency ?

A 1/4 wavelength might well be a measured 29.5, but 29.5 of what ?

#4 poulsbobill Jan 22, 2013 03:26 PM

Thanks for the idea on the antenna. It's ~29mm.

Thanks

Bill

#5 srnet Jan 23, 2013 03:47 AM

Frequency ?

#6 poulsbobill Jan 23, 2013 04:02 PM

Quote:

Originally Posted by srnet (Post 23901541)
Frequency ?

2.4ghz Beyond that how do you tell?

#7 srnet Jan 24, 2013 02:17 AM

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.

#8 poulsbobill Jan 24, 2013 03:22 PM

Quote:

Originally Posted by srnet (Post 23912366)
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

#9 srnet Jan 24, 2013 04:04 PM

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 ?

#10 jakestew Jan 25, 2013 11:13 AM

Quote:

Originally Posted by poulsbobill (Post 23918057)
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.

#11 poulsbobill Jan 25, 2013 09:48 PM

1 Attachment(s)
Quote:

Originally Posted by srnet (Post 23912366)
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

#12 jakestew Jan 26, 2013 01:18 AM

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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