DIY BiQuad 11dbi antenna tutorial! - Page 35 - RC Groups
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Dec 15, 2011, 10:07 PM
Engineer for Christ
IBCrazy's Avatar
No. That will work fine. I do the same thing.

-Alex
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Dec 15, 2011, 10:38 PM
Registered User
Quote:
Originally Posted by IBCrazy
No. That will work fine. I do the same thing.

-Alex
Ok great. I realized what I did after the drilling
Dec 16, 2011, 09:35 PM
WannaBeLikeJoshTheSlowJet
bakchos's Avatar
Hey, anyone care to comment that way of building the biquad,

+ and - ? performance ?

Thanks

SeattleWireless TV WiFi October 2003 (20 min 10 sec)
Dec 17, 2011, 04:05 PM
WannaBeLikeJoshTheSlowJet
bakchos's Avatar
I did the copper tube thing, works great, this is my 1st 2.4Ghz biquad, my 1.2Ghz was working perfectly, can't wait to try this one, i have the bowtie done.

I will drill a hole the size of the wire and pass it from the upper part of the antenna, then i will solder the copper tube to the reflector and crimp my connector to the wire, this should be really strong, 2.4 is so small to work with ! i started with 900mhz 4 years ago.

Here is some pictures of the progress.









All done !! some bling bling fun... i will try it on my router tomorrow and compare with stock antenna.



Last edited by bakchos; Dec 17, 2011 at 11:13 PM.
Dec 18, 2011, 12:53 PM
Registered User
Adekamer's Avatar
very big reflector
it no bad but improved minimal.....
Dec 18, 2011, 04:33 PM
Team White Llama!
gundamnitpete's Avatar
i agree, looks big. That said, it's not really a problem from what i understand.....just bulkier
Dec 22, 2011, 12:18 AM
Registered User
Can I use the RG-174 cable as the feedline for the biquad or the CP double quad?
Dec 22, 2011, 08:28 AM
Engineer for Christ
IBCrazy's Avatar
^Yes. RG174 works no problem.

@Backhos - That is very similar to how I make my professiona BiQuads. The copper tube is there really just for support. You do not need it for resonance. I designed mine the way I did in this tutorial to keep the parts count low.

-Alex
Dec 29, 2011, 02:24 AM
Registered User
Hi Alex,

Sorry for going off-topic, but for the CP double quad antenna, can I replace the RG 62 cable for the RG 58 or RG 174 cable? Thank you.
Dec 30, 2011, 08:08 AM
Registered User
Hello,

Regarding the BiQuad Antenna, I read on a website that when attaching the coax to the feed point it needs to be quite accurate because if it's position is out by only 0.5mm, it can alter the center frequency by as much as 50mhz.

Thanks

Andrew.
Feb 01, 2012, 11:36 PM
Registered User

im just trying to figure out the wave length of 1160mhz


im coming up with 10.4 but want to make sure with you guys here, thanks..
Quote:
Originally Posted by IBCrazy
Since this is a closed loop resonator and I'm going to assume that the pilot is not flying in the rain, there will be no degradation factor. I use a direct speed of light calculation. There are 3 calculations you need:

Full wave length:

Full wavelength in inches = 11732/f in MHz
Full wavelength in cm = 29800/f in MHz
For the following frequencies you have:
910 MHz = 12.89/32.75cm
1280MHz = 9.17/23.28cm
2450MHz (2.4GHz) = 4.79/12.16cm

Section length (this is simply your full wave length divided by 4):

Section length in inches = 2933/f in MHz
Section length in cm = 7450/f in MHz
For the following frequencies, the section lengths are as follows:
910 MHz = 3.22/8.18cm
1280 MHz = 2.29/5.82cm
2.4GHz = 1.197/3.041cm

Element spacing
(this is your full wavelength/8):

Element spacing in inches = 1467/f in MHz
Element spacing in cm = 3725/f in MHz
For the following frequencies, your element spacing is as follows:
910 MHz = 1.61/4.09cm
1280 MHz = 1.15/2.91cm
2.4GHz = .6/1.52cm

That wasn't so hard was it? Now write down those numbers and on to the next step.
Feb 08, 2012, 03:42 PM
Registered User
Is there any way to build the biquad with a wider beam angle? Losing gain is OK, I'd rather have slightly wider coverage. I know with the DIY patch that was accomplished by cutting the panel wider. Anything similar here?

I'm not ready for diversity yet.
Feb 10, 2012, 02:07 PM
Registered User
Alex, any ideas? Is there a way to widen the beam angle of the biquad?

Quote:
Originally Posted by ov3rmind
Is there any way to build the biquad with a wider beam angle? Losing gain is OK, I'd rather have slightly wider coverage. I know with the DIY patch that was accomplished by cutting the panel wider. Anything similar here?

I'm not ready for diversity yet.
Feb 13, 2012, 08:33 AM
Engineer for Christ
IBCrazy's Avatar
Quote:
Originally Posted by ov3rmind
Alex, any ideas? Is there a way to widen the beam angle of the biquad?
Sadly, This is not possible. You can make a UniQuad antenna. I designed it over a year ago, but never introduced it due to switching over to circular polarization.

Here's what you do: Build a single element quad (only half of the BiQuad). Remember that it must be fed from the side, not the top or bottom. Feed the element with 1/4 wavelength (accounting for velocity factor, of course)of RG179 coaxial cable. Splice the other end directly into your feedline.

That's about 9db or so.

-Alex
Feb 21, 2012, 10:54 AM
Registered User
I need a directional antenna for my RC link 2.4Ghz.
I want test BiQuad..
How I increase dbi in BiQuad antenna ? ( about 18 dbi )


Thanks


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