Repurposed antenna


#1

I am curious if I could use the antenna from the wifi camera as a replacement for the stock antenna for the CX-30 board and/or tx?


#2

I’m guessing that if it is a 5.8 ghz antenna it will work for anything that is 5.8 but how well is up for discussion. If it’s a dipole then there are better options for the receiver. I tossed my dipole for my goggles for a cloverleaf.


#3

Looks like a 2.4ghz dipole, should work fine for other 2.4ghz stuff.
Won’t work well for 5.8.


#4

Ok, more questions for this August assembly

I was curious what the bulge on the wifi antenna contained so I cut off the wrap and found… a bell that the larger wire entered and the smaller wire was soldered to it inside the bell and came out of the top. I am assuming the bell is just a housing to make it able to fit the casing clip, am I correct?

I am aware that the wire from the top of the bell is for the wifi, could the antenna on the FC replace the top antenna on the bell and the bottom (grey) wire be connected to the FC’s antenna spot?


#5

That’s what is known as a “sleeve dipole” antenna, both the little wire coming out the center and the bell are active elements, they’re sized to resonate at 2.4ghz.


#6

Thanks for the heads up. better to ask than to make the error of acting on my thought and regretting it (have done quite a bit of that since I got into this hobby)

Any suggestions for improvement of the FC antenna?


#7

You can give it a dipole.
Get some coax cable, find a ground point right next to the antenna signal point on the FC.
Center wire of the coax goes to signal, outer shield of the coax goes to ground.

On the other end that WiFi antenna will work great, though it’s a little heavy.
Just stripping 31mm of shield off the coax and leaving the center conductor hanging out that 31mm will be an improvement over a wire soldered to the FC.

Having 31mm of shield twisted together into a wire and facing away from the center bit is even better, like this:



This RX used to just have 31mm of wire soldered to it for an antenna. This increased range by 50% or so.

The sleeve like the WiFi is the best option, but heavy.

If you want a nice deep rabbit hole to explore, dig into antenna design theory. It’s a mess, but fascinating! It’s essentially magic.


#8

@Bobnova, would you mind explaining this a little better - I can’t really make out the pics and this sounds quite interesting as far as extending the range on my e011’s.

Thanks man


#9

Trick is, your ground point for the coax world needs to be within a few mm of the antenna signal point. Usually you can scrape the solder mask off a pcb ground plane and use that.

The lengths are critical, 33mm or 29mm will result in significant range decreases.