Swan listed in their sale brochure a digital display for the Swan 100MX, but no model number. It has the digital display plug on the radio. Any idea of the model number of the display? Have one for sale?
IIRC the Swan 100mx is a mobile radio and shares a lot of design features with the Swan Astro 102BX base radio. The counter on the 102 measures the local oscillator output and subtracts 9mhz from it. If you can't find a counter you may be able to build one using the 102BX counter as a starting point?