Sander Style For video?

[Anarchy83]

Ok this may be an obvious question to some folks but I was wondering if you could make sander style antennas for 2.4Ghz video tx and rx?

Reason being I have all the parts here to make some sander style antennas and I am in need of some video antennas!

If so what length would they need to be for 2.4Ghz.

Thanks

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[Coyote]

A Sander style antenna for 2.4ghz vtx`s are the rubber duck antennas you get in the box with them. Standard monopole.

[ClippedWing]

Have a look here for sizes and understanding of tuning my friend!
http://www.antenna-theory.com/antennas/halfwave.php

[Anarchy83]

A Sander style antenna for 2.4ghz vtx`s are the rubber duck antennas you get in the box with them. Standard monopole.

Thanks, I did think this. So I just need to replicate these.

[Anarchy83]

Have a look here for sizes and understanding of tuning my friend!
http://www.antenna-theory.com/antennas/halfwave.php

Thanks for the link, very useful. So I take it the standard "rubber duck" monopoles are 1/4 wavelength? So should follow this - http://www.antenna-theory.com/antennas/monopole.php ?

[iPeel]

Thanks for the link, very useful. So I take it the standard "rubber duck" monopoles are 1/4 wavelength? So should follow this - http://www.antenna-theory.com/antennas/monopole.php ?

No, they'll probably be a sleeved dipole. Regardless that's what you will want to build for a VTX / VRX. So two 1/4 wave elements to make up a dipole, one for the driven element, one for the ground plane. So follow the link BenLimeClouds gave you.


Neil.

[ClippedWing]

To be honest with you there a bit pants for video!

You can make a skew or helical for you video that gets rid of multi path signals! Quite easy to make basic ones and you can use the stuff you have :)

The sander style ones are ideal for things like 459mhz or 433mhz not ideal for video!

[Coyote]

Have a look here for sizes and understanding of tuning my friend!
http://www.antenna-theory.com/antennas/halfwave.php

Thanks for the link, very useful. So I take it the standard "rubber duck" monopoles are 1/4 wavelength? So should follow this - http://www.antenna-theory.com/antennas/monopole.php ?

Yes a rubber duck is an electrically short monopole antenna. The link is correct about making the antenna, if your making a monopole then your active element wants to be around 30 - 32mm depending on tuning point for 1/4 wavelength.

Dipoles work better ( but not as good as circular polarization ) in which case you make two elements each of 1/4 wavelength.

[Anarchy83]

Have a look here for sizes and understanding of tuning my friend!
http://www.antenna-theory.com/antennas/halfwave.php

Thanks for the link, very useful. So I take it the standard "rubber duck" monopoles are 1/4 wavelength? So should follow this - http://www.antenna-theory.com/antennas/monopole.php ?

Yes a rubber duck is an electrically short monopole antenna. The link is correct about making the antenna, if your making a monopole then your active element wants to be around 30 - 32mm depending on tuning point for 1/4 wavelength.

Dipoles work better ( but not as good as circular polarization ) in which case you make two elements each of 1/4 wavelength.

Again thanks for this. I am not planning flying long distances. Planning on using it for an edf jet, so mainly flying around the runway so monopole should be more than what I need.

So if 2.4Ghz 1/4 wavelength is only around 30-32mm is it worth making them 1/2 wavelength i.e 60-64mm.

Would this improve anything?

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[iPeel]

So if 2.4Ghz 1/4 wavelength is only around 30-32mm is it worth making them 1/2 wavelength i.e 60-64mm.

Would this improve anything?

No, a 1/2 wave dipole made from 1/4 wave elements is optimal, see this video.

As previously said though circular polarised are better for short ranges as they cancel out reflections. Arguably linear antennas are better for longer ranges.


Neil.

[Anarchy83]

So if 2.4Ghz 1/4 wavelength is only around 30-32mm is it worth making them 1/2 wavelength i.e 60-64mm.

Would this improve anything?

No, a 1/2 wave dipole made from 1/4 wave elements is optimal, see this video.

As previously said though circular polarised are better for short ranges as they cancel out reflections. Arguably linear antennas are better for longer ranges.


Neil.

Wow learnt so much already. So if I made half wavelength mono,  this will actually generate a full wavelength and therefore no radiation is produced. I will stick with 1/4 wavelength. May try a cloverleaf,  see how I get in with these monopoles.

What is the actual formula for finding the correct size for antenna length?

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[Devonian]

What is the actual formula for finding the correct size for antenna length?

[/quote]

Speed of light (in metres per second) divided by frequency (for a full wavelength), divide this by 4 to get a quarter wave.

So, we can use:
300/2400/4 = 0.03125 metre (or 31.25mm)

HTH

Nigel.

[Anarchy83]

What is the actual formula for finding the correct size for antenna length?

Speed of light (in metres per second) divided by frequency (for a full wavelength), divide this by 4 to get a quarter wave.

So, we can use:
300/2400/4 = 0.03125 metre (or 31.25mm)

HTH

Nigel.
[/quote]

That's a great help.  Thanks!

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[Anarchy83]

Based on this formula,  Why does Sander make the 433Mhz monopoles 164mm long? Surely they should be 173mm?

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[FPVSteve]

Er, are we sure light only does 300m per second? I beg to differ :laugh: