Antenna working & signal trnsmission

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I've few doubts in deciding which antenna to use in my project . Please help me 1. How one can know the gain (dB) of an antenna when constructing it & on what basis gain will be calculated? 2. What will happen if two antennas of different gain (dB) are used at Transmitting & Receiving sides.
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Anji

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Posted 4 years ago

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Andrew MacTaggart, Champ

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Anji

those are some loaded questions, and I must say that I am not an expert. I think it's one of those Areas where you either have a mentor or learn from trial and error.

A. You must define the scenario that the external Antenna will be used to solve.

2.How one can know the gain (dB) of an antenna when constructing it
Assuming you are not building your own Antenna,
You must study the datasheets from the antennae provider, gain, polarity, e-plane, h-plane etc...
See if you can get loaners to test with from the Antenna provider of choice, Passive gain is added to the transmit power minus the cable loss, connectors etc...., You must review the regulations for your region when comes to frequency, power levels, etc...

2A.on what basis gain will be calculated? Not sure what you mean? But you select the correct tool for the right job. So if you are doing PTP project of several kilometres distance you need to select the correct Antenna for that purpose.

3. What will happen if two antennas of different gain (dB) are used at Transmitting & Receiving sides?
For PTP this is often done to align the Antennae. Once the Antennae are lined up then power can be raised.

There are so many factors to take into consideration that it is difficult to cover them all, but that is why they write books.

Might I suggest reading
There is a plethora of info in the whole CWNP series of books.

Cheers
A





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Anji

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Thanks for your response sir.
What exactly i want to ask is, i'm using 5dB antenna at transmitting side & 12dB antenna at receiving side. So, 12dB antenna will transmit at different signal strength (with strength more than 5dB can does) compared to 5dB antenna. Can 5dB antenna receive the signal properly ?

What i've in mind is that, 5dB antenna means it may not receive/transmit signal strength more or less than 5dB. Sorry for if i'm wrong. Hope you u can understand now
(Edited)
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Andrew MacTaggart, Champ

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Hi Anji

The best advice I can give you, is that you contact an Antennae seller that also provides professional services and they can make recommendations for your situation.

cheers
A