The Tait TB7100 is an FM repeater. It's a relatively simple device made up of two TM8100 series radio boards, a “User Interface” board that allows the operator to change channel etc, and a “System Interface” board that does some some signal conditioning, basic logic, and fan control.

A batch of Multitone pager transmitters have recently appeared on eBay. These are a TB7100 chassis with a single 50w VHF radio fitted on the transmit side, and an additional “paging interface board” to re-map some of the internal connections and condition the incoming AFSK paging signal before its transmitted.

As-is they're probably not much use to amateurs as paging is commonly on UHF and other applications will require access to the Rx audio, but it's relatively easy to either convert them back into a duplex repeater, or re-route the connections internally so we can access both the Tx and Rx audio on the single radio.

In my opinion this is worth the effort, as the chassis provides a nice 1U rack mount platform with power distribution and suitable cooling for high duty cycle operation. There's also room for some combination of a duplexer, AC power supply, NinoTNC, MMDVM, or Raspberry Pi.

• The speaker and volume control on the UI board are hard wired to the absent receive radio, so monitoring the transmit side isn't possible without modification
• Likewise any Rx audio outputs on the DB25 system connector are also hard wired to the absent receive radio, so won't output any audio without modification.
• The UI panel requires 13.8v and 3.3v, which is normally taken from the receive radio. In its absence, the paging interface board takes 13.8v from the auxiliary connector on the Tx radio, and drops it down to 3.3v. If the paging interface is removed, the UI panel will malfunction. Modifications are required to resolve this.