On 02/12/2017 16:49, Rob wrote:

There are of course other receivers that use the same method, e.g.
the Racal RA14 and the Yaesu FRG-7.

ITYM RA17? Had one but had no room for it so disposed of it


It is quite common to use shaft encoders to interface a spinning knob
to a microcontroller that sets the frequency of the synthesizer.
Normally a numeric digital readout is used with those, as it is usually
more convenient than a linear scale. However, there is no reason why
you could not mimic a linear scale on a dot-matrix display.

Actually, having retired from a career as electronics engineer and
real-time embedded softy, it would all be well within my capabilty
but I eschew the bus driver's holiday, having considered coupling a
tuning knob to a 4096 gray scale shaft encoder to read the cursor
position, and so I find the 12" slide rule scale with large spiining
knob to be a personably-preferable haptic solution.


In fact, today usually an SDR is used with a "waterfall" display, that
looks like a linear scale where you can see all nearby transmissions
at the same time and can tune by sliding it to the position you want
to listen to using a spinning knob. But unlike a classic receiver
(without panoramic adapter) you can SEE what you will be tuning to,
making it much more convenient than just blindly tuning around.


I prefer some operating skill instead of everything handed on a plate
and also eschew the DX cluster as being a dishonourable technique :-)