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Shared RX/TX ground plane antenna
Posted: Mon Dec 27, 2010 1:48 pm
by hplus
Hi,
I've bought a RFXCOM RX and TX few month ago, and i am facing some transmission/reception problems.
I don't change the position of the rfxcom nor the position of the emitting device ( a digimax thermostat) but sometimes i stop receiving a signal during couples of hour (5h). I understand collisions could sometimes make the message unreadable. But the likelihood of having collisions for 6*5=35 consecutive transmission is very low (the digimax transmit each 10min or so)
So i was thinking it could be a reception range problem and i am going to use a ground plane antenna. Can i connect both the RFXCOM TX and RX on that same antena?
What do you think about that?
Thanks
Hplus
Re: Shared RX/TX ground plane antenna
Posted: Mon Dec 27, 2010 2:26 pm
by esschenk
Hello,
The answer is no.
for receiving and transmitting you need 2 antenna's
I think you must try first the receiving part
The transmitter is strong enough for my whole house.
Ed
Re: Shared RX/TX ground plane antenna
Posted: Mon Dec 27, 2010 2:52 pm
by AshaiRey
That's correct, you need 2 antenna's.
It's solved a few range problems for me
Re: Shared RX/TX ground plane antenna
Posted: Mon Dec 27, 2010 3:42 pm
by b_weijenberg
Do you have receiving problems and/or problems when using the RFXCOM transmitter?
If you discover receive problems on the RFXCOM receiver you probably have another RF signal that disturbes the sensor signals. Another antenna with a higher amplification will increase the receive problems in this case. It can be any device that produces a RF noise at 433.92MHz.
If you experience problems with the transmitter it can also be that the receiver modules (like KAKU) also receive that RF noise signal that blocks the RFXCOM receiver. If you have range problems with the RFXCOM transmitter you can connect a telescopic 433.92 antenna
http://www.rfxcom.com/receivers.htm#89001 to the transmitter or a groundplane
http://www.conrad.nl ordernr: 190073 (officially not allowed because the transmitter is certified with wire antenna)
Re: Shared RX/TX ground plane antenna
Posted: Mon Dec 27, 2010 10:58 pm
by DMB
I use a groundplane for the 433 MHz reception, another groundplane for the 868 MHz visonic reception and the telescope from the RFXCOM site for the 433 MHz transmitter with good results in the house and outside the house over a range of 30 meters.
DMB

- Groundplane rfxcom
- groundplane rfxcom.jpg (14.79 KiB) Viewed 6283 times
Re: Shared RX/TX ground plane antenna
Posted: Sat Jan 15, 2011 1:25 am
by hplus
Sorry for the late reply.
I've got a ground plane antenna now, i've put it on my receiver. it's better.
I want to use my telescopic antenna on my transmitter how to solder a bnc male conector on the transmitter instead of the yellow wire?
the is 2 connection on the bnc the internal wire should be soldered on the same pin as the wire antenna, but where to connect the shield?
Re: Shared RX/TX ground plane antenna
Posted: Sat Jan 15, 2011 10:25 am
by b_weijenberg
You will find next to the connection point where the yellow wire is a ground connection point for the BNC.