antenna question - Page 1
Forum section: electronics / beginners

author: christos10
author_rank: Contributor
timestamp: March 08, 2014, 11:27:44 pm
content: hello, im trying to build a biquad antenna .theres many (how to do it) in youtube and in google..the question is that they say every side of the antenna needs to be at 30.5mm..i got a digital meter and cant get it so close..im geting it at 31mm or 29..do it need to be exactly 30.5mm?thx

author: IanB
author_rank: Super Contributor
timestamp: March 08, 2014, 11:46:19 pm
content: Quote from: christos10 on March 08, 2014, 11:27:44 pmI doubt 0.5 mm either way will make much difference. But...try harder to get it exact. Precision in workshop skills will always be valuable.

author: christos10
author_rank: Contributor
timestamp: March 08, 2014, 11:57:36 pm
content: as much i try,cant get it exact..im using a 2mm wire,shoud i measure at the center of the wire (x)(x is the center) or at the end? x() when they make the biquad antenna ..i dont think they make it exactly 30.5mm..they just wrap it around and done

author: GreyWoolfe
author_rank: Unknown
timestamp: March 09, 2014, 02:29:08 am
content: Is this a receiver only or a transceiver? If it is a receiver only, it won't be so critical, if it is a transceiver, it is better to electrically match the antenna to the transceiver as that will keep the VSWR and reflected power at a minimum. Even if it is just a receiver, I agree with IanB and do your best to get as close as possible. It will hone your construction and problem solving skills.

author: Rory
author_rank: Frequent Contributor
timestamp: March 09, 2014, 03:26:13 am
content: Looks like he's trying to extend his wifi range.http://trevormarshall.com/biquad.htm

author: G7PSK
author_rank: Super Contributor
timestamp: March 09, 2014, 09:09:34 am
content: Google bending allowances, to make it easier for you here is the wiki link on bending, it gives a formula but most people will just work from a chart or even rule of thumb.http://en.wikipedia.org/wiki/Bending_(metalworking)http://www.engineersedge.com/bend_allow_calc.htmhttp://sheetmetal.me/bend-allowance/These are talking about sheet metal but its the same for wire as well.

author: christos10
author_rank: Contributor
timestamp: March 09, 2014, 09:42:30 am
content: Quote from: Rory on March 09, 2014, 03:26:13 amyes,im trying to extend my wifi range but also to see how these antena works..

author: christos10
author_rank: Contributor
timestamp: March 09, 2014, 09:50:04 am
content: Quote from: G7PSK on March 09, 2014, 09:09:34 amthx ..now i need to find a better way to bend the wire ..i was doing it with my thumb..2 sides was perfectly 30.5mm and the other was way out of the measurements

author: christos10
author_rank: Contributor
timestamp: March 09, 2014, 09:51:25 am
content: Quote from: GreyWoolfe on March 09, 2014, 02:29:08 amim doing it for a receiver ..will 0.5mm do so much difference?

author: GreyWoolfe
author_rank: Unknown
timestamp: March 09, 2014, 01:34:03 pm
content: Quote from: christos10 on March 09, 2014, 09:51:25 amFor the receiver, the .5 mm isn't that critical. Try using needle nose pliers for the bends. When I want a neat bend or am bending through hole component leads, the needle nose pliers makes it look nice. Using the pliers might help you get that .5 mm perfect

author: sacherjj
author_rank: Frequent Contributor
timestamp: March 09, 2014, 01:52:57 pm
content: To bend something like that for a one of, I'd hammer accurate 16 penny nails into a scrap of plywood and make a jig. That would get the critical bend points and all you would need to do is manually get the angle right. Just draw the shape on the board and put the nails to the inside of the bend.

author: christos10
author_rank: Contributor
timestamp: March 09, 2014, 08:31:20 pm
content: what ever i try dosent help..if i draw the antena on the wood with each side 30.5mm..the wire then get to 34.5mm..do the wire need to be in the midle? i mean ,the wire is 2mm 2mm/2+30.5mm=31.5mm(if you cant understand what i mean,,ask me to make a drawing and send it to you)

author: G7PSK
author_rank: Super Contributor
timestamp: March 09, 2014, 09:47:26 pm
content: The wire stretches as you bend it that's why you need to calculate the bend allowance for precise bending.