Better than sat-nav

SIR – Dag Pike (Letters, August 31) makes a good case for Britain to use e-loran instead of satellite navigation systems.

The original Loran system was first used in the Second World War. It used high-power ground-based transmitters with large aerial systems, rather like a BBC medium-wave transmitter.

It was very difficult to interfere with: after the war, radio hams were allowed to transmit on the same section of the 160M band that it used, and although we suffered interference from Loran I never heard of a complaint the other way round.

Sat-nav systems rely on weak high-frequency signals from distant satellites, and can easily be interfered with. This could affect services that rely on them. Do the police and fire brigade still carry maps?

Harry Leeming

Morecambe, Lancashire