transmitter and receiver sharing antenna

[JTM]

I want to use a Radiotronix 433 MHz transmitter and reciever together (so I
can TX and RX from the same device) and want to know if there is a way I can
use the same antenna for both.

 

[the Wiz]

Yes. For a low power transmitter, you can use the proper switching/isolation
diodes to connect the antenna to the receiver until the transmitter is turned
on.

For higher power, you can use an RF-rated relay to switch the antenna between
the transmitter and receiver.

John

"JTM" <jtm@yahoo.com> wrote:

I want to use a Radiotronix 433 MHz transmitter and reciever together (so I
can TX and RX from the same device) and want to know if there is a way I can
use the same antenna for both.

More about me: http://www.jecarter.com/
VB3/VB6/C/PowerBasic source code: http://www.jecarter.com/programs.html
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Drivers for Pablo graphics tablet and JamCam cameras: http://home.earthlink.net/~mwbt/
Email here: http://www.jecarter.com/contactme.htm

 

[Captain]

"JTM" <jtm@yahoo.com> wrote in message
news:uJ2Bc.3301$1F6.1776@fe37.usenetserver.com...

I want to use a Radiotronix 433 MHz transmitter and reciever together (so
I
can TX and RX from the same device) and want to know if there is a way I
can
use the same antenna for both.



It depends on the bandwidth ofthe antenna and whether or not you want to

operate in simplexx or duplex mode.

Simplex is simple, all you do is use a relay or diodes to switch between
transmitter and receiver and you can use the same frequency for both
transmit and receive. You cannot, of course, receive while you are
transmitting.

Duplex, that is, the ability to transmit and receive simultaneously, on the
other hand, requires different frequencies for transmit and receive and
usually an isolator circuit between the tx and rx parts of your radio. An
accurate, high power, notch pass filter, tuned to the receive frequency is
also useful. The frequencies should be far enough apart that the transmit
signal can be filtered successfully from the receive signal, hence the
bandwidth of the antenna becomes critical.

If you need to use duplex operation then you need to do a bit of studying,
designing and building. Simplex operation is well named!

Regards

Cap

 

[JTM]

I'm thinking it might be better to just power down the RX and power-up the
TX as needed.

I found some ascii-art on the web on the use of diodes to share an antenna,
but can't seem to find it again. The schematic was simple but they
mentioned the diode selection was critical. Can someone provide the details?
Thx.


"Captain" <Captain7@rochester.rr.com> wrote in message
news:WUrBc.367097$M3.15706@twister.nyroc.rr.com...

"JTM" <jtm@yahoo.com> wrote in message
news:uJ2Bc.3301$1F6.1776@fe37.usenetserver.com...
I want to use a Radiotronix 433 MHz transmitter and reciever together
(so
I
can TX and RX from the same device) and want to know if there is a way I
can
use the same antenna for both.



It depends on the bandwidth ofthe antenna and whether or not you want to
operate in simplexx or duplex mode.

Simplex is simple, all you do is use a relay or diodes to switch between
transmitter and receiver and you can use the same frequency for both
transmit and receive. You cannot, of course, receive while you are
transmitting.

Duplex, that is, the ability to transmit and receive simultaneously, on
the
other hand, requires different frequencies for transmit and receive and
usually an isolator circuit between the tx and rx parts of your radio. An
accurate, high power, notch pass filter, tuned to the receive frequency is
also useful. The frequencies should be far enough apart that the transmit
signal can be filtered successfully from the receive signal, hence the
bandwidth of the antenna becomes critical.

If you need to use duplex operation then you need to do a bit of studying,
designing and building. Simplex operation is well named!

Regards

Cap

 

[Jamie]

Duplexer


JTM wrote:

I want to use a Radiotronix 433 MHz transmitter and reciever together (so I
can TX and RX from the same device) and want to know if there is a way I can
use the same antenna for both.