simple 2.4GHz antenna

djsfantasi

Joined Apr 11, 2010
9,156
Do you plan on making it as your only option? Since your an RF and antenna newbie, maybe buy an antenna.
A quick search shows many commercial solutions for an antenna for you, such as this one.
Shipping from the US is likely prohibitive, so I supply that link only as an idea.
I don't know if you can get one locally, but that (and a similar) antenna is between USD 2.75 and 5.00
 

Thread Starter

bug13

Joined Feb 13, 2012
2,002
Do you plan on making it as your only option? Since your an RF and antenna newbie, maybe buy an antenna.
A quick search shows many commercial solutions for an antenna for you, such as this one.
Shipping from the US is likely prohibitive, so I supply that link only as an idea.
I don't know if you can get one locally, but that (and a similar) antenna is between USD 2.75 and 5.00
Hi djsfantasi

I am open to any suggestion, I understand that I don't have RF and antenna knowledge. I will buy one from supplier if I have to, but If I can connect something I have now to just test it, that will be great. My goal is to get it good enough to talk to each other and do some current tests.

So If I get one from a supplier, can I just solder a 50 ohms coax to the antenna and my little module?
 

Lestraveled

Joined May 19, 2014
1,946
The wavelength (in air) of 2.4 GHz is 4.92 inches. A quarter wavelength is 1.24 inches. Take a piece of coax and cut the shield back 1.24 inches and you are done.
 

KJ6EAD

Joined Apr 30, 2011
1,581
There are lots of instructions online for making improvised 2.4 GHz antennas from coax cable, tubing, cans and other junk. You'll probably get enough range and not damage anything by removing the shielding from 12.5 cm of coax center conductor.

Edit: This would make a rough full wave antenna. Les has given you the 1/4 wave version above.
 

Thread Starter

bug13

Joined Feb 13, 2012
2,002
How about picking up a used 2.4GHz WiFi router and pulling the antenna off of that?
Good idea, I will if I can find one, thanks!

The wavelength (in air) of 2.4 GHz is 4.92 inches. A quarter wavelength is 1.24 inches. Take a piece of coax and cut the shield back 1.24 inches and you are done.
There are lots of instructions online for making improvised 2.4 GHz antennas from coax cable, tubing, cans and other junk. You'll probably get enough range and not damage anything by removing the shielding from 12.5 cm of coax center conductor.

Edit: This would make a rough full wave antenna. Les has given you the 1/4 wave version above.
Just to confirm, do you mean something like this??
 

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Thread Starter

bug13

Joined Feb 13, 2012
2,002
BTW, what is the different between using an 1/4 wave, 1/2 wave or full wave antenna?

Thanks!
 

MikeML

Joined Oct 2, 2009
5,444
Just to confirm, do you mean something like this??
No. It should look like this:






The coax shield braid is folded back along the outside of the vinyl. The sleeve is not connected at the bottom end. You can leave the inside insulator on the whip portion. The dimensions are a few inches, not 8ft, which would be for the 28MHz amateur band...
 
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Lestraveled

Joined May 19, 2014
1,946
Putting metal close to a 2.4 GHz antenna will turn a great SWR into a very bad SWR. So, the transmitters in the 2.4 GHz devices have to be very fault tolerant when it comes to SWR. Building a temporary test antenna should be a pretty casual exercise. I say that any of the above examples will work fine for in-shop testing. Don't worry about exact measurements, you would need a network analyzer to get it perfect.
 

Lestraveled

Joined May 19, 2014
1,946
Bertus
Excellent resource site for bug13's project. Very good find.

Bug13 - suggest you look at "antenna construction" on the page bertus linked to. Lots of good stuff.
 

Thread Starter

bug13

Joined Feb 13, 2012
2,002
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