NavList:

Peter Smith you wrote: A boat I used to sail on had a B&G Herron RDF. Bearings were taking with a very similar "Sestrel" hand-held compass with a dipole antenna added on. It was heavy, but very stable and capable for either visual or radio bearings.

When I bought TIKI in 1989, she had the Seafarer one with a ferrite rod aerial.  I could get the BBC on 200/198kcs and occasionally the UK East Coast light houses which in those days used to come up in sequence on 303kcs.  The radio wasn’t much kop, but the little plastic compass on the top was rather good despite its small size.  You could light it up with a tiny pea-bulb in the body of the radio.  Shortly after, I bought a small inexpensive digital output Decca receiver, which operated on the lane ident signals only but could provide a continuous position of about three miles accuracy.  Such luxury.  Eventually GPS came along, and the MDF and Decca stations were switched off.

Re the O6a, Paul Brewer has kindly sent me a working drawing and some words from the RAF manuals.  DaveP