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Old Feb 01, 2016, 09:06 AM
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Quote:
Originally Posted by z4ibas View Post
Stupid question:

You are working with antennas many years, maybe do you know some other ways to test antennas with home equipment?
I wish it were that simple. However, at these frequencies, it is not... You need specialized gear for this stuff.

-Alex
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Old Feb 12, 2016, 06:51 AM
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Hi guys,

Sorry if this has been already cleared, for 2.4GHz, 30.5mm or 31.5mm.
I am not sure how to measure my antenna.

I intend to build this - http://martybugs.net/wireless/biquad/
and this -
Omnidirectional Biquad Antenna for 2 4GHz (9 min 0 sec)
to work together.

For the first one, it seems to be clear, 30.5mm measured from center wire to center wire. I did this by measuring my initial wire in 30mm sections and then bending at 90 degrees, so that the mark falls exactly in the corner.

For the second antenna, apparently I need a 31.5mm "measuring tool" so that in the end this will give me what section size? I guess it will be slightly more than 31.5 due to the bending, but the author says that the sections need to be 31.5mm... ok, lets say 31.5 from center wire to center wire.

Will these 2 antennas work together? They are both calculated for 2.4GHz, only that one uses 30.5 and the other one 31.5mm.

I tried yesterday using a piece of metal of exactly 30mm to bend my wire (hoping that would give me 31.5 in the end) and I got a measuring of 32.5 approx from center wire to center wire. I guess its unusable for 2.4GHz right?
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Old Feb 12, 2016, 09:09 AM
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*Sigh* Bi = 2 Quad = 4. BiQuad literally translates as "2 squares". What you have there is often called a "spire antenna". They help make a more uniform pattern out of the single loop bisquare antenna. Gain is around 5dbi, which isn't bad, actually.

The antenna is very wide-band and thus perfection is optional. it will work well even if the measurements are off.

-Alex
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Old Mar 05, 2016, 12:00 PM
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Is this correct?
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Old Mar 06, 2016, 08:34 AM
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Looks good to me. Go and fly it. You will like it

-Alex
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Old Mar 28, 2016, 02:35 PM
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Lightest Weight Reflector

I am looking for the lightest weight reflector so itís easier on my antenna tracker. Also want something non-magnetic.

Is there a minimum thickness for the reflector metal? Can I use a PC board with thin copper coat?

.
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Old Mar 31, 2016, 08:33 PM
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If you read through the previous posts in this thread, you'll see that your questions have already been answered.
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Old Apr 04, 2016, 05:56 AM
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I have a VAS commercial BiQuad on my antenna tracker but would like a little more range. I am flying 1258 Mhz. I am thinking of building a dual biquad (I think that’s what it’s called – the one with 4 loops). I have two questions.

1. Is the spacing between the reflector still 1/8 wavelength?
2. How do I compute the dimensions for the reflector? I would like to make it less than twice as wide as that would be too large. I know that Alex said that you could go smaller on a standard BiQuad. Is there a formula?

.
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Old Apr 06, 2016, 01:36 AM
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Quote:
Originally Posted by RC Man View Post
I am looking for the lightest weight reflector so itís easier on my antenna tracker. Also want something non-magnetic.

Is there a minimum thickness for the reflector metal? Can I use a PC board with thin copper coat?

.
Mesh screen works well. Hard to find in non-magnetic, though. PC board works fine if you can get one big enough.

-Alex
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Old Apr 06, 2016, 01:38 AM
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Quote:
Originally Posted by RC Man View Post
I have a VAS commercial BiQuad on my antenna tracker but would like a little more range. I am flying 1258 Mhz. I am thinking of building a dual biquad (I think thatís what itís called Ė the one with 4 loops). I have two questions.

1. Is the spacing between the reflector still 1/8 wavelength?
2. How do I compute the dimensions for the reflector? I would like to make it less than twice as wide as that would be too large. I know that Alex said that you could go smaller on a standard BiQuad. Is there a formula?

.
More range than a BiQuad on 1258? Are you going 50 miles or something? If not, I would take a good look at your control system. Chances are your control transmitter is spewing noise onto the band. The common black DVR's that most FPV retailers sell also spew noise on 1258Mhz. Just moving the DVR farther away from the antenna helps a lot.

To answer your question on the double BiQuad: yes and yes

-Alex
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Old Apr 06, 2016, 05:45 AM
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I am trying to get good range with a low power VTX (200mw or less). I also have a few trees that get in the way on the ground station end. Your commercial BiQuad works fairly well. I was just in the mood of building something myself.

.
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Old May 19, 2016, 01:47 AM
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RG58 vs RG6

Quote:
Originally Posted by IBCrazy View Post
You need the following materials:

1 sheet of sheet metal (thickness doesnít matter much. I used 26 gauge galvanized steel)
2 nylon bolts (I used ľĒbolts)
1 coaxial cable (I used RG58/U)
1 length of solid copper wire (I used 14 AWG)

Tools:

Tape measure
Soldering iron
Solder
Calipers (optional)
Drill

That's it. There's not much to this one!


I want to make my own 5.8GHz biquad antenna following your tutorial.Can I use a RG6 coax (75ohm) for it? I see ppl are talking about RG316 ..BUT i have some RG6 cables left in my house.
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Old May 23, 2016, 08:01 PM
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Originally Posted by adnanbrc View Post
I want to make my own 5.8GHz biquad antenna following your tutorial.Can I use a RG6 coax (75ohm) for it? I see ppl are talking about RG316 ..BUT i have some RG6 cables left in my house.
No. Use RG316 cable. You can find it on Ebay cheap

-Alex
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Old Yesterday, 04:55 PM
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Quote:
Originally Posted by RC Man View Post
I am looking for the lightest weight reflector so itís easier on my antenna tracker. Also want something non-magnetic.

Is there a minimum thickness for the reflector metal? Can I use a PC board with thin copper coat?

.
Look at post #845.

I used a scrap foam board piece with kitchen aluminum wrap taped on it. Have been using it for past several months and it still works

That'd be the lightest reflector I can think of!
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