How to use a single antenna with two transceivers.

I have two transceivers. One main and another for backup. Now I am using two separate antennas for the two transceivers. Is there any device with which I can use both the transceivers with a single antenna? As mentioned already, all the parameters are same for both the transceivers and I have a switching mechanism to activate the secondary transceiver if the main one fails.

Any help would be appreciated.

Why you don't use a switch between antenna and transceivers?
Would be simplest way!

What kind of switch do you mean?

Dpending on the power level and frequency you can either use a semiconductor switch (e.g. GaAs) or coaxial relays.

Switch maybe a good solution. You have a photo/schematic of this devices ? The tranceivers are half/full duplex? I say this cause maybe you have problem with inteferences

http://www.rlcelectronics.com/index....Itemid=5&id=41

use pin diode to make a switch,and you'd better receive the two signals by time division

Power level is 1 watt and frequency it is the ISM 434 MHz band.

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The transceivers are half duplex, and I wont be using both transceivers at the same time. The second transceiver has the same configuration as the first one and it is only for redundancy.

Do you expect the second transceiver to take over automatically in the event the first fails, or can it be with manual human intervention?

If it can be done with human intervention, then personally my solution would be to unscrew the antenna feeder from one transceiver and screw it onto another. Total cost S0. If not a manual coaxial switch. At one Watt, assuming your transceiver would accept 1 mW without damage, then you only need an isolation of 30 dB, which is nothing really.

If you want the second transceiver to take over auotmatically if the first fails, then it is a whole different ball game.

Dave

The redundancy tranceiver is connected to your circuit or you have it for backup when the first fails? I mean, this will work at the same time with the main tranceiver? explain a little more about the use of redundancy tranceiver

George

I need it to take over automatically. The transceiver will automatically switch over. but my doubt is how do I use one antenna with both the transceivers? Will a coaxial switch do the job as biff44 suggested?

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The redundancy transceiver will automatically take over, if the primary fails. Both the transceivers are connected to a main control circuit which will do the switching automatically. I want to use one common antenna instead of using two antennas for the two transceivers (just to save space). If I am using a switch what should be the minimum isolation?

The switch I posted is a little overkill for 1 watt transmit power. You can use pretty much any electromechanical latching type RF relay switch at those power levels. The switch will not know when your transmitter has failed, so you will have to generate a signal separately to switch it into the standby transmitter position.

You could fairly easily find a semiconductor switch to do the same thing, but the electromechanical latching relay is probably a little more robust.

You'll find GaAs switches with up 10W power handling from major manufacturers, e.g. Hittite, RFMD or Skyworksinc. Reliability requirements may suggest a mechanical relay though.

What kind of failure events are we talking about here? If you're just worried about the transceiver dying due to downstream conditions, then a solid state switch should be fine. But if you're worried about lightning hitting the antenna, then you're looking at a much bigger issue...

I have the same question. when and why a traneiver fails? i am a begginers so explain it simply if you can

George