[Premium-Rx] Preselectors

[GandalfG8 at aol.com]

In a message dated 28/11/2007 22:52:21 GMT Standard Time,  
michaelob666 at ntlworld.com writes:

I'll add my sixpence worth of wisdom to the debate.  
If you  want to see "real" preselectors with proper switches and variable 
capacitors you  basically have to look at non-PR radios - typically the oldish 
Racal RA1772 (mid  70s).  
The only two PR radios I know of with motorised preselectors are  the Redifon 
R500 (a work of much beautyand expense) designed for warships and  all the RF 
nasties that you find on board, and the Eddystone 1650 (but it was an  
expensive option).
The fact is that motorised preselectors are uneconomical  nowadays unless you 
are in a very hostile situation with masses of RF next  door.
-----------------------------------

Hi Michael
 
I wish my wisdom was worth sixpence:-)

An interesting point  with the Redifon R500 was that many modules, including 
the central processor  unit, were shared with the DU500 drive unit and this 
extended to the  "preselector" module, although now used as a post-selector.
Redifon  conveniently called it the "tuner module" though, so didn't even 
have to worry  about changing the description between units.

I don't know whether  or not the deigners would have added an internal motor 
tuned post selector to  the DU500 if it wasn't that their design philosopy 
dictated it was "already  there" so to speak, but it's the only one I've come 
across that's built into a  drive unit and it certainly is a beautiful piece of 
engineering.
Aside  from these two units it's also found in the R501 and DU505 and perhaps 
other of  the 2000 series too.

Coming back to receivers, one shouldn't, of  course, forget the pinnacle of 
warship ballast engineering, that en mass in  racks probably weighed more than 
the hull and all the armaments put  together.....small fanfare for...the 
Marconi ICS3 reseiver:-)
I'm sure you'll  agree they don't come much more premium than this, and the 
motorised preselector  there is the alloy lump in the rear left hand  corner.

regards

Nigel
GM8PZR