Low Power Isolator

While upgrading the repeater to include the 90 watt power amplifier, I stumbled onto this low power isolator on eBay. It is an Alcatel device that covers the amateur 900 band quite nicely. Inserting the isolator between the exciter output and the PA input results in a stable 50 ohms to both ports.

Network analyzer plots of the isolator.

This series of close-in plots shows 20 to 25 dB return loss on both ports, less than 0.2 dB insertion loss and better than 20 dB of isolation.

These plots show the wideband return loss and insertion loss characteristics of the isolator.