[TenTec] D-104 and Paragon

[J. Reed]

Thank you 'Jerry' for the link to the D-104 'Z' conversion... looks 
great and I will build one for my venerable D-104.  Jim Reed.
  ----- Original Message ----- 
  From: Jerry Volpe 
  To: Discussion of Ten-Tec Equipment 
  Sent: Thursday, May 05, 2005 02:26
  Subject: Re: [TenTec] D-104 and Paragon


  The stock D-104 requires a very, very high impedance for it to operate 
  with its designed frequency response curve. Depending on the vintage of 
  the crystal element it works best from somewhere between 1.5 meg and 3 
  meg input load impedance. When the mic element is swamped down into a 
  much lower load value the microphone output takes on a very pinched 
  sound with little lows or lower mid range audio. This may sound ok to 
  some when used for DX or contest type operation but under normal chat 
  communications it will sound very thin and easily over-driven. The 
  impedance of the Paragon mic circuit is from somewhat to significantly  
  less than 1 meg depending on the capacitive reactance of a capacative 
  voltage divider. Check the schematic to see what the D-104 is looking 
  into. Certainly not as bad as other 'modern' transceivers but still not 
  what the Astatic crystal element was designed to work with.

  Check out the following link:

  http://members.cox.net/n4jk/d104.htm

  This was the buffer amplifier that I put in my D-104. The resultant 
  audio is rich with fulness with the slight upper mid-range bump in 
  frequency response needed for voice clarity. I have compared, 
  on-the-air, a stock un-amplified D-104, a stock amplified D-104, and my 
  modified D-104. Not trusting to other's opinions I did multiple 
  recordings with my voice keyer and then transmitted from the Omni-VI+ 
  and the Paragon to my Jupiter with the audio openned up. The difference 
  was more than remarkable and turned many a skeptic back toward the D-104.

  Have fun!

  Jerry, KG6TT


  >I have used my D-104 (vintage, stock and non-amplified version) with my Omni 
  >6 Plus for years with great results. I would imagine that the tx audio input 
  >for the Paragon is similar to the OMNI 6 Plus and therefore should work very 
  >well. I would avoid the newer "amplified" D-104's.
  >
  >  
  >
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