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Same Antenna for transmission and reception

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raiya_23

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Can the same antenna be used for transmission and reception when the transmission and reply frequencies are 63Mhz apart?
 

Re: Same Antenna for transmissino and reception

Hello,

This depends on the useful bandwidth of the antenna and the link budget. Mostly reception can have more reflection (higher VSWR) with respect to transmission. Of course you may lose some S/N ratio, but when you have sufficient margin, this should not be a problem.

So you may design the antenna for best/good VSWR in the transmitting frequency range and accept some higher VSWR in the receiving frequency range. For a more specific answer, you may give us some additional info.
 

Re: Same Antenna for transmissino and reception

I am confused because we learnt in college that the length of an antenna depends upon the frequency on which it is being used (lentgh equals to 1/4 of wavelength) so according to this there should only be one antenna for one frequency but I saw in a transmitting station a single antenna being used for several frequencies so how is that possible?
 

Re: Same Antenna for transmissino and reception

Because each antenna have freq band itself, it is not single freq point, it is band.
 

Re: Same Antenna for transmissino and reception

Means each antenna length caters to a specific frequency band and not a specific frequency?
 

Re: Same Antenna for transmissino and reception

Means each antenna length caters to a specific frequency band and not a specific frequency?

You have not specified the nominal frequency band you want to operate your antenna in.

If the TX and RX frequencies are 63 MHz apart at say 1 GHz, you can use a filter diplexer to use one antenna for both ways at the same time.

If you need to use one antenna with TX and RX at the SAME frequency, you must use a time separated operation, a duplexer. A duplexer is a switch connecting the antenna to the TX to transmit while blocking the RX from a high TX power.
 

Re: Same Antenna for transmissino and reception

It also depends on the kind of the antenna.
Some antennas have a small band while others are very wide band antennas, for example antennas used in cell phones or cars.
If you use an antenna that covers the frequency band you need this should be possible.
 

Re: Same Antenna for transmissino and reception

Can the same antenna be used for transmission and reception when the transmission and reply frequencies are 63Mhz apart?

Hi.
yes ofcourse but you dont connect an antenna both at the input reciver tuner and RF output of transmitter as same point connection so you must use a " QRP " circuit at your transciver.
although you can use a relay to connect the antenna to transmitter output when you push microphone's Key and disconnect that antenna from reciver's tuner independently.
The QRP is a simple circuit usually used afew of component such as diode and capacitor and Resistor.
If you need some of them PLZ contact me .
angrygtnote@gmail.com
Tehran-Iran
 

Re: Same Antenna for transmissino and reception

Is the QRP ckt a coupler?

Hi.
yes ofcourse but you dont connect an antenna both at the input reciver tuner and RF output of transmitter as same point connection so you must use a " QRP " circuit at your transciver.
although you can use a relay to connect the antenna to transmitter output when you push microphone's Key and disconnect that antenna from reciver's tuner independently.
The QRP is a simple circuit usually used afew of component such as diode and capacitor and Resistor.
If you need some of them PLZ contact me .
angrygtnote@gmail.com
Tehran-Iran
 

Re: Same Antenna for transmissino and reception

you can use a split duplexer to use same antenna for both frequencies, but there should be a slight difference in the both frequencies..i.e Rx and Tx
 

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