From: g@crcomp.net   
      
   See addendum at bottom.   
      
   Liz Tuddenham wrote:   
   > Dave Platt wrote:   
   >> Liz Tuddenham wrote:   
   >>   
   >> >At 200 c/s switching frequency, 1N4148 sounds far more attractive -   
   >> >eapecially as I have a drawer full of them.   
   >>   
   >> The Ramsey DF1 Doppler direction finder works by switching an array   
   >> of four dipole antennas into and out of the receiver circuit, using   
   >> 1N4148 diodes as switches, at a rate of 1 kHz.   
   >>   
   >> I haven't heard of any of these wearing out :-)   
   >>   
   >> The DF1 works fine at 2-meter frequencies, and I can recall using   
   >> in the 70 cm band as well.   
   >   
   > I wondered if I might be re-inventing the wheel but couldn't find an   
   > exact equivalent already in existence.  There are three questions with   
   > this system:   
   >   
   > 1)  Is it likely to work?  I think you have answered that with a "Yes" -   
   > as long as I can engineer it correctly.   
   >   
   > 2)  If it works, what use is it.  I envisige it being used for DF-ing   
   > faint signals.   
   >   
   > 3)  Who would want to DF faint signals?  I don't know the answer to   
   > that, so it looks as though I have invented a solution that is looking   
   > for a problem.   
      
   Perhaps it can alert a ham to hit the dirt when it detects an incoming   
   FPV drone crossing a battle line?   
      
   Thank you guys for another interesting thread. The manual for the DF-1   
   mentioned by Dave is available at:   
      
      
      
   Addendum:   
      
   AI acts as an acceptable, although now and again fallible, search   
   engine front end. A little prodding can increase its precision.   
       For instance, although the above archive link contains the phrase   
   "schematic diagram" the diagram itself is blank. With a little   
   prodding, AI returns a better result:   
      
      
      
   Not only does n0zyc provide the schematic missing from the earlier link,   
   he embellishes it. He enumerates its errors, adds corrections, and   
   presents an improved design.   
      
   --   
   73, Don, KB7RPU                                           veritas    _|_   
                                                             liberabit   |   
   https://www.qsl.net/kb7rpu                                vos         |   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)