[Elecraft] High power tuner

[Gary VK4FD]

Vic,

I'm waiting for a KPA-1500 with the inbuilt auto-tuner.....oops, gotta run, the nice young man in the white coat is calling me again....


Gary


VK4FD - Motorhome Mobile
Elecraft Equipment
K3 #679, KPA-500 #018
Living the dream!!!

  ----- Original Message ----- 
  From: Vic K2VCO 
  To: elecraft at mailman.qth.net 
  Sent: Sunday, November 27, 2011 9:00 AM
  Subject: Re: [Elecraft] High power tuner


  The balanced output is not referenced to the case. So the balun is functional when feeding 
  a balanced line, not shorted as you suggest. However, you are correct that it will not 
  serve as a common mode choke with unbalanced output. And Paul's comments about the 
  placement of the balun are correct. I was surprised to see this from Alpha, whom I would 
  have expected to know better.

  I suppose I'll have to wait for the KAT1500 (no, no such product has been announced or 
  hinted at as far as I know!)

  On 11/26/2011 8:55 AM, Joe Subich, W4TV wrote:
  >
  >> The new RF Concepts tuner would not work well for me. It's an
  >> unbalanced C-L-C design with a CM choke input, similar in design
  >> with several Palstar tuners, only with much more rugged components
  >> than what Palstar provides. W9CF, W7EL, and W8JI have analyzed a
  >> current choke placed at the input to a C-L-C tuner and have concluded
  >> that placement at the input is not as effective for maintaining line
  >> balance as a balun placed at the tuner's output.
  > The common mode choke in the Alpha tuner will be completely ineffective
  > with any of the coaxial fed antenna outputs in any case!  Since it is
  > *inside* a metal box and the input as well as output connectors are all
  > connected to the case, any common mode current will simply bypass the
  > the choke on the case!
  >
  > The *only way* to make a common mode choke effective with an unbalanced
  > tuner is to connect the case of the tuner to a low impedance "ground"
  > and place the choke in the feedline between the rig/amplifier and the
  > tuner - external to the tuner.
  >
  > 73,
  >
  >      ... Joe, W4TV
  >
  >

  -- 
  Vic, K2VCO
  Fresno CA
  http://www.qsl.net/k2vco/

  ______________________________________________________________
  Elecraft mailing list
  Home: http://mailman.qth.net/mailman/listinfo/elecraft
  Help: http://mailman.qth.net/mmfaq.htm
  Post: mailto:Elecraft at mailman.qth.net

  This list hosted by: http://www.qsl.net
  Please help support this email list: http://www.qsl.net/donate.html