[Amps] Building or Buying a Tuned Input Network

Gary Schafer garyschafer at comcast.net
Mon Jan 23 14:38:09 EST 2006



> -----Original Message-----
> From: Vic K2VCO [mailto:vic at rakefet.com]
> Sent: Monday, January 23, 2006 2:24 PM
> To: garyschafer at comcast.net
> Cc: 'Roger D Johnson'; amps at contesting.com; 'Tony King - W4ZT'
> Subject: Re: [Amps] Building or Buying a Tuned Input Network
> 
> Gary Schafer wrote:
> >
> > Having a fixed input cap and fixed inductance you can not vary the
> center
> > frequency of the circuit.
> 
> There is some available inductance variation by squeezing/separating the
> turns on thre toroid.  As I said, I had good luck making the input
> capacitor variable and the output fixed, but one could certainly make
> *both* variable to maximize the amount of twiddling possible!
> 
> --
> 73,
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco

The Sb200 has fixed caps on input and output and a slug tuned coil. Tuning
the coil moves the center frequency while the swr remains relatively
constant.

73
Gary  K4FMX




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