I have an automated transceiver with a single antenna that periodically transmits a 50-750ms pulse at 900MHz to 1.1GHz with about 7 watts of power. In between pulses, it's a receiver at that frequency range. Is there a clever way to externally suppress the transmissions completely, without interfering with the receiver function?
The suppression needs to occur outside of the box, via a circuit on or in the coax or at the antenna, as opening the box and modifying the internals is not an option. Even general ideas on how one could go about getting this achieved would be greatly appreciated.

 

IIRC a circulator could be used to divert the TX into a dummy load and leave RX working.

 

kubeek: I hadn't heard of such a thing. Is this similar to what's used in radar setups?

 

No idea about radars. Its a passive device that sends whatever comes to port 1 to port 2, 2 to 3 and 3 to 1. So if you connect your device to port 1, RF terminator that handles that 7W to port 2 and your antenna to 3, then you get what you need. But you need to choose one that fits the bandwidth, has enough RF separation between the ports and can handle the power.

 

Hello,

Here are a couple of pages wich explain the working of the circulator mentioned by @kubeek
http://www.radartutorial.eu/17.bauteile/bt33.en.html
http://www.novamicro.com/understanding-circulator-and-isolaters.php

Bertus

 

Thank you kubeek and bertus. Someone clever always comes thru on this forum!