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Old Oct 27, 2012, 03:34 PM
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Woww that is big!

I see that you painted the bowtie, I assume it's ok to do so. What about in my case the copper PCB as well?
Shinny copper catches too much attention in the park. I wanted to color it in a more discrete way.
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Old Oct 27, 2012, 03:38 PM
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Originally Posted by tushev View Post
Tadaaa!! my version is ready to be tested
Looks good, buddy! Wait until you fly it

-Alex
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Old Oct 27, 2012, 04:43 PM
Still hackin'
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433 bi-quad

I built a bi-quad for 1240MHz - a mate was so impressed he made a 70cm one for himself as well
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Old Oct 27, 2012, 09:45 PM
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Quote:
Originally Posted by IceWind View Post
Woww that is big!

I see that you painted the bowtie, I assume it's ok to do so. What about in my case the copper PCB as well?
Shinny copper catches too much attention in the park. I wanted to color it in a more discrete way.
Paint won't hurt it at all.

-Alex
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Old Nov 10, 2012, 03:59 AM
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bi-quad awsome

after reading this whole thread yesterday and a trip to maplins i made this 5.8ghz bi-quad





it works although as yet no range testing
i have been getting 450m on cp antennas and immersion long range vtx with fat shark goggles in less than ideal conditions

things that are wrong with my bi-quad
messy solder around post
id like a thinner post anyway this one is 5mm i want 4mm
wire is 0.92mm it should be 0.59mm

i read that the shape of the lobes is unimportant so long as they are symetrical and 1 wavelength, its very hard to make a square of wire this small and keep it to 1 wavelength and equal sides so i think the next one i will make 3/4 circular with small straigts at 90 degrees into the post.

once proved and working with my hexacopter and ground station tracker ill be making one for my control tx 2.4ghz

thanks for this informative thread - im very much inspired

Aitch
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Old Nov 11, 2012, 05:40 PM
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Today I couldn't use my favourite combination of Vee + Biquad and instead I had to use another quad that has one of these antennas.


(900MHz 1/2 Wave 2dBi Antenna)

I know they aren't center tuned to 980Mhz that I use but I was expecting to at least have clear video at close range. Instead I got always noise, either close or far, of course with distance it would get even worse but in overall the image quality was horrible...
Is it just because of the antenna not been tuned to 980Mhz or is it because this type of antenna don't work well with the BiQuad?
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Old Nov 12, 2012, 08:56 AM
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I'd suspect something is wrong with the antenna.
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Old Nov 12, 2012, 01:17 PM
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Check ther is a centre pin in there
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Old Nov 12, 2012, 08:44 PM
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Oh yes that one is there.
I still get image and it works for 400/600mts... but it's awfull. Next weekend I'll run some tests and see if I can capture some video from the GroundStation.
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Old Nov 15, 2012, 09:30 AM
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update on the 5.8ghz biquad

not actually about the biquad but have range tested the system again with 2 cp antennas and im getting just over 1km

have materials on order now to build an RHCP BI-QUAD and ill be range testing that back to back with current set up

Aitch
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Old Nov 20, 2012, 07:35 AM
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Thanks for the design and instructions! I just made one for 2.4 GHz. I used a 0.5mm copper plate for a reflector, and wow, was that a mistake. Soldering anything to that massive heat-sink is near impossible. Maybe I'll re-make it with a copper-plated PCB some other time. I haven't tested the antenna yet, but I had a chance to plug it into a meter, take a look at that return loss on the last picture. Is it normal for this kind of antenna? Mind you, my feed is very long at the moment, maybe 1.5 meters.
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Old Nov 20, 2012, 11:14 AM
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MXM000 - Your return loss looks a bit unstable. You might have a defect in the cable (or the feed) causing some resonance effect. This could be skin effect tracking down the tube. Your second major trough in your plot is most certainly skin effect of the signal tracking down the tube.

-Alex
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Old Nov 25, 2012, 07:39 PM
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Quote:
Originally Posted by IBCrazy View Post
MXM000 - Your return loss looks a bit unstable. You might have a defect in the cable (or the feed) causing some resonance effect. This could be skin effect tracking down the tube. Your second major trough in your plot is most certainly skin effect of the signal tracking down the tube.

-Alex
Hi Alex just building another of these for myself as they are wicked!
With what you are saying in the above post do you mean the ground is not connected well enough to the tube?

I only ask because I have no means of testing antennas at the mo and for the biquad normally I use a tube attached to the reflector that is a tight fit to the ground when pushed through then fold a bit of the ground sheath over then solder that.
Do you think this is sufficient?

Thanks

John
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Old Nov 25, 2012, 08:00 PM
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What I am saying is that at certain frequencies the tube actually becomes resonant no matter how it is connected due to skin effect. There's nothing you can do about it other than put a ferrite ring around it. I wouldn't bother, though. You are building it just how I build mine: a tight fit tube.
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Old Nov 25, 2012, 10:08 PM
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Quote:
Originally Posted by IBCrazy View Post
What I am saying is that at certain frequencies the tube actually becomes resonant no matter how it is connected due to skin effect. There's nothing you can do about it other than put a ferrite ring around it. I wouldn't bother, though. You are building it just how I build mine: a tight fit tube.
Thanks
Always worked well just checking. can always be better
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