Yes, the real Parasets did have a mechanical reduction drive - a couple of washers under the small knob pinched a skirt on the periphery of the big tuning dial/knob. I played around with trying to homebrew one for my "real" Paraset I hope yet to build. The reduction seemed like it would be maybe 8:1 or 10:1, with a 180 degree max shaft rotation of the main tuning cap.
The tuning range was from 3.3 to 7.6 Mc, So if it was even as much as 10:1 that would be 4.3 Mc per 5 revs, or a bit over 650 kc for a 270 degree rotation of the tuning knob (compare that to our puny 150 kc per 270 degrees on the BJ). And you guys were worrying about the BJ's fast tuning! :^))
Of course, remember that London had powerful transmitters with multiple rhombics, so it wouldn't have been so hard to find London. And agent-to-agent contacts were pretty much taboo, so Parasets didn't need to find other Parasets.
---In 4sqrp@..., <davemrtn@...> wrote :
Reading 'The Secret Wireless War', I came to [page 92, paragraph 7) a sentence about the 'Paraset' (Whaddon MkVII) saying -
"With no 'fine tuning' control, the receiver was not easy to use by anyone lacking 'safe-breaker's fingers'."
My first thought was "what the heck kind of fingers are those?". A google search turned up a link about "Safe Crackers", so that made the light go and I realized what the writer meant.
Also, his comment about no "fine tuning" must have meant no "electrical" fine tuning, because looking at a photo of a MkVII Paraset on the following page, there appears to be a fine tuning knob of sorts, albeit a mechanical method.