Installed Xref-VT board on my ICOM 910. The board is obtained from VK3HZ . The XRef-VT take a 10 MHz reference signal from a GPS reference or other high accuracy source and provide a precision reference frequency.  This eliminates the problem of radio being off frequency and drifting as it warms up.  If the 10 MHz reference signal is not available, the board reverts to using its onboard TCXO as its source. In the case of the Icom IC-910, the reference frequency is 30.2 MHz. For more information go to VK3HZ page.

Connection points for Xref-VT board

SMA socket to feed in 10MHz ref on rear panel

The Xref-VT board in place

Rubidium 10MHz source connected to the radio