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Old Jul 11, 2011, 07:06 AM
Gamble with Gravity
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Joined Jun 2011
65 Posts
Sounds like noise floor to me. Something tells me that biQuad was aimed right at the interference source as well as your truck. There is no reason for a whip antenna to beat a high gain antenna when you are within the beam.
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Old Jul 11, 2011, 02:42 PM
summitmk3
roadgraders's Avatar
United States, NE, Alliance
Joined Jul 2010
483 Posts
Quote:
Originally Posted by Gamblerman View Post
Sounds like noise floor to me. Something tells me that biQuad was aimed right at the interference source as well as your truck. There is no reason for a whip antenna to beat a high gain antenna when you are within the beam.
I don't know what's going on. I'm not a guru at any of this...I'm just confused???
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Old Jul 13, 2011, 07:23 AM
summitmk3
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United States, NE, Alliance
Joined Jul 2010
483 Posts
Went out and tried a regular patch antenna and was a lot happier with the results. Although it didn't go any further on that particular road it worked better in the hills to the side of the road.
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Old Jul 15, 2011, 10:21 PM
I think it'll work this time!!
Chairwolf's Avatar
399 feet above Roanoke, VA
Joined Jan 2007
3,443 Posts
Great stuff! Subscribed.
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Old Jul 18, 2011, 08:05 AM
SpliceMILK, BeverlyHills,CA
LexusFPV's Avatar
Joined Feb 2011
1,200 Posts
How high off the ground should a BiQuad be?

I know its not ground dependent like the Patch antenna.

I'm using 1.2ghz frequency and I have 2x BiQuads on a Diversity(VidRx).
I have a "V" antenna on my 3meter Glider.

Should the BiQuads be 6 feet off the ground or higher?

I have gone 8km out, but I want to go out further.
The higher the BiQuad antenna's off the ground, should I be able to go out further distance?
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Old Aug 01, 2011, 06:58 PM
Registered User
Joined Apr 2008
356 Posts
hi guys, hi ibcrazy,

thanks for all info you provide, you're an hero

i'm going to build a 1010mhz biQuad for my fppv station. I'm going to use a copper clad pcb board as reflector, but i'm in trouble finding one 300x300mm piece. My question is: can i use two (or more) smaller boards glueing them together? Apart the mechanical problem, do the copper interruption makes some negative effect on the reflector function? and what if i solder junction?
thanks for the info
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Old Aug 01, 2011, 08:35 PM
Registered User
KL,Malaysia
Joined Jun 2008
35 Posts
Hi Guys,

Flew a LOS flight a couple of weeks back with home brew IBcrazy's Biquad for 1040 Mhz for the first time. Much better reception than the standard vrx whip antenna and this is with a HK 100mW Vtx thru' a quarter wave wire on an Easystar. Reflector is from a piece of thin metal sheet ( roofing material) and quad made from brass welding filler rods with a short length of satellite tv cable to the receiver..

You can just catch a glimpse of the setup/biquad on a chair at the start of the video.

Kc

fpvglenmarie16thJuly2011.m4v (6 min 12 sec)
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Old Aug 04, 2011, 07:00 AM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,060 Posts
Quote:
Originally Posted by GliderLover View Post
hi guys, hi ibcrazy,

thanks for all info you provide, you're an hero

i'm going to build a 1010mhz biQuad for my fppv station. I'm going to use a copper clad pcb board as reflector, but i'm in trouble finding one 300x300mm piece. My question is: can i use two (or more) smaller boards glueing them together? Apart the mechanical problem, do the copper interruption makes some negative effect on the reflector function? and what if i solder junction?
thanks for the info
That should work fine. Go ahead and build it. Be sure to post pictures!

-Alex
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Old Aug 05, 2011, 02:48 AM
Registered User
Joined Mar 2006
7 Posts
Poor reception

Hi,

I made a Bi Quad for 1.2GHz frequency :
section length : 6.21 cm (used 6.19cm)
element space : 3.10cm
total length : 49.67cm (used 49.5cm)

Please :
1/ How is measured element space ? from the wire center section to the bowtie ?
2/ Is section length difference (6.19 instead of 6.21) very important ?
3/ Is total length difference (6.19 instead of 6.21) very important ?

Today, my BiQuad is not better than the orignal 3db antenna sold with the receiver...

Here are some attached pictures of my antennas, if you can see an big mistake, could you tell me what is it please.
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Old Aug 05, 2011, 05:31 AM
You can't take the sky from me
Rastislavko's Avatar
Slovakia, Bratislava Region, Bratislava
Joined Jun 2006
748 Posts
JLC_BOULOT: Man, your design is wrong. Absolutely. You must not run both + and - pole of antenna parallel each other like on that picture. The + must be shielded - that's why it must run all the way up in the shielded tube.

You have to redo this part - I think it will work much better then...
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Old Aug 05, 2011, 06:49 AM
Registered User
Joined Mar 2006
7 Posts
Thanks a lot Rastislavko !!!!

I'll make changes as soon as I can !
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Old Aug 05, 2011, 08:29 AM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,060 Posts
The change that Rastislavko suggested will turn that antenna from bad into the best antenna you have ever flown

-Alex
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Old Aug 06, 2011, 06:43 AM
Registered User
Joined Mar 2006
7 Posts
Exact reference

Thanks for your answers.

I saw IBC antenna a few months ago, and when I had time to make one, I used first link I found... but was not IBC !!! But antenna looked like his...

here the link, it is said it works perfectly :
http://www.modelisme.com/forum/aero-...ion-video.html

Man who works in the only electronic shop I go, is not able to recognize antenna connector... and I'm starting to not believe at all in his radio skill !

I looked on internet, and found so many different SMA plugs...

I'm going to order radio components (plugs and cable RG58U), so could you please tell me where I can get information to know exactly what is this SMA plug ?
I'd like to get connector to solder antenna wire as you guessed.
I suppose radio impedance is 50ohms, I couldnt get this data on my receiver datsheet.

Thank you for your help.
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Old Aug 06, 2011, 07:49 AM
You can't take the sky from me
Rastislavko's Avatar
Slovakia, Bratislava Region, Bratislava
Joined Jun 2006
748 Posts
Quote:
Originally Posted by JLC_BOULOT View Post
I'm going to order radio components (plugs and cable RG58U), so could you please tell me where I can get information to know exactly what is this SMA plug ?
This is not SMA connector. It's called "F-connector". SMA is a little smaller.
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Old Aug 06, 2011, 09:10 AM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,060 Posts
You can always just buy an adapter. You need an F male to SMA female adapter. You can find them on Ebay for cheap.

-Alex
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