[Linnovice]

This is not strictly a ‘vintage’ radio question but hopefully you may be able to guide me in the right direction.
I have a small collection of FM tuners that I enjoy listening to, mainly R3. They range from a Troughline to Linn Kudos and include a Stereofetic, Sansui and Trio. All in good condition having been thoroughly serviced, recapped, new valves (where necessary) and realigned.
They are fed from a five element rooftop external aerial and are only fed one at a time. ie. there are no splitters involved, I move the connection as necessary. This aerial is aimed at the Wrotham transmitter which is approximately 75 miles away (I live in Tiptree, Essex).
My problem is that the signal I receive seems to be a bit low. ie. on the Troughline the magic eye valve only just about moves when tuned. The Kudos only shows about 65% on its strength meter. None of them have any full deflection on the meters. There are no significant hills or tall buildings in the path so I’m assuming it’s just a distance thing. The reception is ‘ok’ but I can’t help but feel that it should be better.
Would anyone care to recommend a booster or perhaps, an alternative remedy please?
Mike