Both Gee and Loran were based on the the same principle – hyperbolic Navigation. The main difference being that Loran operated on lower frequencies to achieve longer range. That is probably why the sets looked similar.

Loran was in use at the end of WW2 because (according to Wikipedia) trials in the US during the war were so successful the whole system was up-rooted and re-located to the west of the European continent to assist US and UK bombers find their targets. It was useful in that it was more accurate at night, which suited Bomber Command very well.

Apologies for thread drift here but, if Loran was better (and the later Loran-C better still), then why did the RAF continue to use Gee until well after the war (in their Canberras, for instance) when Loran was mature and better as a system by then?

A nice find, Spark Plug, though more interesting than valuable. I would be interested to know what the story was behind this particular piece. Looking at the picture on the Wiki site, the fascia looks like that from an APN-4 Loran set. Interestingly, it states that this set was interchangeable with Gee sets so, apart from the frequencies it must have been pretty much identical equipment.

Thanks for posting SP. An interesting and intriguing start to the New Year.

Anon.