Second hand satnav with external aerial?

[Mr Scruff]

Simply... I love my elderly S8 but the coating on the windows means that neither of my portable satnavs work (TomTom 1 and a Garmin something), nor does my Sony Android phone satnav or my wife's iPhone.

Have some long journeys coming up and would like to have a satnav. Could anyone suggest a satnav I might be able to find (ideally second hand) which has the capability of using an external aerial? Fair to say I'm reasonably 'price sensitive' so second hand preferred but will go new at a push.

Thanks!