0b1a9952   
   XPost: rec.radio.shortwave   
   From: DPeterMaus@att.net   
      
   On 11/27/11 21:15 , rrusston@hotmail.com wrote:   
   >   
   >>   
   >>    Valves have a place in audio, for the truly faithful. But then,   
   >> audio only requires a few valve types, frequencies are easily   
   >> managed, and circuitry remains stable for much longer periods of   
   >> use.  Whereas radio applications require more sophisticated valve   
   >> construction, and significantly different valve types for given   
   >> applications, to accomodate frequencies that stretch from 10X to   
   >> 100000X audio frequencies.   
   >>   
   >>    What's comforting in radio with valve technology, is the general   
   >> sense that the technology itself is accessible. And widely   
   >> understood to be more forgiving. That valves may be removed, tested,   
   >> and replaced by the techologically limited, and operated under   
   >> conditions that would destroy solid state. Whereas, SS receivers,   
   >> self service requires a much higher level of skill, with a much   
   >> lower threshold of abuse. For those with limited technological   
   >> experience, this can be daunting. Especially, as in the case of this   
   >> receiver, during an emergency, where supply lines are uncertain, and   
   >> technical support is nonexistent.   
   >>   
   >>    I can see where the OP is coming from. Build an accessible   
   >> receiver that's fairly forgiving to extremes in noise, signal   
   >> levels, voltage, and hostile events, and you'd have a generally   
   >> useful rig for the general population in an emergency. It's a nice   
   >> thought.   
   >>   
   >>    But as has been pointed out here multiple times, SS technology in   
   >> a proper design has proven more resistant to EMP than generally   
   >> believed, operating voltages are easier to generate, and manage,   
   >> power requirements are lower, and performace of the technology is   
   >> dramatically improved since the days of valve receivers. All at a   
   >> fraction of the cost. And in an emergency, valve supplies will be   
   >> just as short as SS components.   
   >>   
   >>    All of which points to the fact that a well designed kit radio for   
   >> use in emergencies would be more like the Ten-Tec 1254, than it   
   >> would be like a Hallicrafters S-40. And the Ten-Tec 1254 is a kit,   
   >> costs $200, and requires no user alignment, but offers significant   
   >> performance across the spectrum from LF through HF.   
   >>   
   >>    In a package that's available now.   
   >   
   >   No regen offers simplicity of use and selectivity, nor is the demod   
   > audio very good in most cases.   
   >   
      
      
        Ten-Tec 1254 is a superhet.   
      
      
   >   A real SW-3 with a transformer in place of the watchcase headset was   
   > tested by a friend in a screen room with HP test gear for SINAD and   
   > audio quality. The rig consisted of HP, 8640B and 339A as I recall and   
   > minimum AM distortion was six or seven percent, but that was only at   
   > something like -20 dBm input and 60% modulation. I can't remember what   
   > SINAD was.....it was dismal.   
   >   
   >   Passive TRF sets, i.e., "crystal radios" were capable of very good   
   > fidelity OTOH. The old Millen was capable of equaling the test set's   
   > own performance. Again you had to drive the hell out of it though.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)