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2.4ghz Antennas

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Old 11-21-2006, 12:05 PM
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Default 2.4ghz Antennas

Have anyone tested wlan 2.4ghz antennas on the Airplane instead of the stock 3db antennas?

I'm considering this omni antennas, with a little modification (like weight reduction) tehy could work better than the stock 3db antennas of the transmitter.


Omni 6db antenna $19.99



(2) Omni 9db antennas $49.99 (the package comes with 2 antennas you can sell the other one).

For those high tech guys, could I use 2 antennas with the transmitter one antenna on each wing?



I searched online for those homemade 2.4ghz antennas but they're to heavy and big.

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Old 11-21-2006, 12:39 PM
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Default RE: 2.4ghz Antennas

There is NO advantage to using two antennas on your video TX. That setup is designed for receivers and routers where there is receiving going on. A video transmitter has no way to switch between two antennas and no way chose the best one....

No need to modify those antennas... There are small ones available that will work fine for you already made. BWAV sells the shorter antennas, and also longer higher gain antennas that will screw right onto your video TX.

Be careful, the inside of the plug on those antennas you pictured is DIFFERENT than your video TX, the threads are the same size, but the inside of the plug is female instead of male [:@]

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Old 11-21-2006, 01:31 PM
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Default RE: 2.4ghz Antennas


Quote:
ORIGINAL: JettPilot

There is NO advantage to using two antennas on your video TX. That setup is designed for receivers and routers where there is receiving going on. A video transmitter has no way to switch between two antennas and no way chose the best one....

No need to modify those antennas... There are small ones available that will work fine for you already made. BWAV sells the shorter antennas, and also longer higher gain antennas that will screw right onto your video TX.

Be careful, the inside of the plug on those antennas you pictured is DIFFERENT than your video TX, the threads are the same size, but the inside of the plug is female instead of male [:@]

JettPilot
I was talking about using a Y SMA adapter coming out of the trasmitter and then to the 2 antennas.

Also I have to correct you about the antennas, they can be used for receiving and transmitting, because WLAN routers use both, receiving and transmiting signals. Routers transmit more than they receive. Both antennas are SMA male connectors and the transmitter is female SMA
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Old 11-21-2006, 01:34 PM
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Default RE: 2.4ghz Antennas

But the difference is a wifi uses a diversity setup. It's constantly reading the signal from the two antenna and deciding which one to use. Simply putting two antenna on a Y connector is not going to do anything beneficial. In fact, you could end up promoting multi-path errors by doing that. You need to have the intelligent circuity to decide which antenna to use.
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Old 11-21-2006, 01:40 PM
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Default RE: 2.4ghz Antennas


Quote:
ORIGINAL: twinturbostang

But the difference is a wifi uses a diversity setup. It's constantly reading the signal from the two antenna and deciding which one to use. Simply putting two antenna on a Y connector is not going to do anything beneficial. In fact, you could end up promoting multi-path errors by doing that. You need to have the intelligent circuity to decide which antenna to use.
True that, but I can use (1) of the antennas 9db is better than the 3db right?
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Old 11-21-2006, 02:43 PM
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Default RE: 2.4ghz Antennas

No. The gain of the antenna comes from the directionality. The more directional the antenna is, more gain it has. If you put the directional antenna on the transmitter, you will receive it only when the beam is pointed right into the receiver. The high gain omni directional antennas work by emitting the radiation in the narrow cylinder around the antenna. There is very little energy that gets emitted above and below the antenna. As a result, you will see the beam only when the plane is tilted in a such way that the beam hits the receiver on the ground.

Use the low gain omni directional antennas on the transmitter side.

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Old 11-21-2006, 03:07 PM
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Default RE: 2.4ghz Antennas

Quote:
ORIGINAL: Marro

No. The gain of the antenna comes from the directionality. The more directional the antenna is, more gain it has. If you put the directional antenna on the transmitter, you will receive it only when the beam is pointed right into the receiver. The high gain omni directional antennas work by emitting the radiation in the narrow cylinder around the antenna. There is very little energy that gets emitted above and below the antenna. As a result, you will see the beam only when the plane is tilted in a such way that the beam hits the receiver on the ground.

Use the low gain omni directional antennas on the transmitter side.

Miro
I was thinking the same thing until I read some reviews from this antenna on google.

They say that improved wifi signal 10 floor up. The router was located on the lobby so the signal instead of going 360 horizontal, it also got better performance 90 degree up.
I already bought a 10db patch antenna for the receiver.

I was thinking about this home made antenna but I don't know how much db gain it has, or if is omni oro omni directional. (also the connector have to be modified to work on a sma or add an adapter.


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Old 11-21-2006, 03:41 PM
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Default RE: 2.4ghz Antennas

Best bet is to use a 3dbi or 6 dbi whip on the plane. That gives the best possible RF radiance given the multiple scenarios/orientations of the plane. Then use a high gain patch, yagi, etc. on the receiver if you plan on flying far away.

Go here and check out the various antenna available: http://www.hyperlinktech.com/web/rub...antenna.php#24 They have rubber duck, patch, yagi, etc. And most of the antenna also show the gain patterns in the horizontal and vertical fields. This is handy in seeing how an antenna will perform for your particular application.
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Old 11-21-2006, 04:23 PM
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Default RE: 2.4ghz Antennas


Quote:
ORIGINAL: twinturbostang

Best bet is to use a 3dbi or 6 dbi whip on the plane. That gives the best possible RF radiance given the multiple scenarios/orientations of the plane. Then use a high gain patch, yagi, etc. on the receiver if you plan on flying far away.

Go here and check out the various antenna available: http://www.hyperlinktech.com/web/rub...antenna.php#24 They have rubber duck, patch, yagi, etc. And most of the antenna also show the gain patterns in the horizontal and vertical fields. This is handy in seeing how an antenna will perform for your particular application.

Exactly. The above antenna would probably work better than standard whip antenna (due to included ground plane - the 4 wires bent downwards), but I don't think it's designed for 2.4 Ghz. The wavelength of 2.4 Ghz iz 12.491 cm. Divide that in half and you get 6.25cm (2.46") as the length. The ground plane length should also be adjusted. The angle controls impedance.

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Old 11-21-2006, 05:56 PM
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Default RE: 2.4ghz Antennas

Found the perfect one $9.99 = 5.5db





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Old 11-21-2006, 11:48 PM
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Default RE: 2.4ghz Antennas

Looks pretty good. Make sure it has the right connector on it. The site I linked to has something called an RP-SMA which is a reverse polarity SMA. I'm not sure why they do that, but apparently some devices put the ground connection on the center wire. I'm pretty sure that might affect the range slightly if not connected to an RP-SMA device!
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Old 11-22-2006, 07:52 AM
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Default RE: 2.4ghz Antennas


Quote:
ORIGINAL: twinturbostang

Looks pretty good. Make sure it has the right connector on it. The site I linked to has something called an RP-SMA which is a reverse polarity SMA. I'm not sure why they do that, but apparently some devices put the ground connection on the center wire. I'm pretty sure that might affect the range slightly if not connected to an RP-SMA device!
All of them are RP-SMA and they say is for :

Applications Include:

2.4 GHz ISM Band
IEEE 802.11b and 802.11g Wireless LAN
WiFi Access Points
Bluetooth®
Wireless Video Systems
Multipoint and Mobile Applications

This sucks.
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Old 11-22-2006, 08:03 AM
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Default RE: 2.4ghz Antennas

I was looking for this antenna long time ago for my router, but forgot the name until now.

is a homemade antenna 2.4ghz with 8db gain, small size. looks promissing. (Alamost 3D coverage)

http://www.olotwireless.net/catala/discono.htm



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Old 11-09-2007, 07:23 PM
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Default RE: 2.4ghz Antennas

Cheap, easy to make RX aerial is the Bi-Quad. Just needs to be made as accurately as possible ~12dB gain. iInstructions here http://martybugs.net/wireless/biquad/ They work very well.
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Old 12-04-2007, 06:34 PM
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Default RE: 2.4ghz Antennas

that bi-quad antenna looks pretty easy to build, maybe I might give it a try building it
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