[Premium-Rx] Preselectors

[Tim Shoppa]

"Michael O'Beirne" <michaelob666 at ntlworld.com> wrote:
> 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.

On my 135 foot doublet up about 90 feet, I get about 70V P-P from a local
BCB blowtorch literally a few blocks away. I can hook up a neon lamp and
watch it light on modulation peaks. Is that at least moderately 
hostile, if not warship hostile? :-).

I suspect a lot of places in Europe have similar RF energy.

*All* consumer SW radios have nothing but images up and down the spectrum
from the local BCB stations, and that's often with their little whip
antennas. Most of my older equipment with tuned circuits in the front
end does just fine.

Funny, I just looked at the specs of my WJ-8716, and it says you're
only supposed to have 1.5V of RF coming into the antenna jack. Hah!

Obviously for many purposes I have a 630kc trap hooked up to take
out the majority (but not all) of the local blowtorch.

Tim.