Re: [Drakelist] T-4XB neutralization?

[WA3WOM]

Thanks Bob!!!  Now you have my curiosity up... I will look for dots and also 
try to adjust it lower and then move up to 10 Meters.
73
WA3Worn-Out-Mike
  ----- Original Message ----- 
  From: Robert Ladden 
  To: Drakelist@zerobeat.net 
  Sent: Thursday, August 28, 2008 11:49 PM
  Subject: Re: [Drakelist] T-4XB neutralization?


  I use GE's in my T-4XC and they neutralized easily without modification, with 
the variable cap near half meshed (pretty good). Oddly, I had RCA's that I 
could not neutralize. But by the 1970s it was hard to tell who really made what 
tube. Look for a series of dots by the tube number stamp. Tubes with the dots 
probably were really made by GE, sometimes for other brands (I read this 
somewhere and I have a batch of GE's and off brands with dots).

  Sometimes it is hard to find the sweet spot on 10m. Try starting on 15m or 
20m and then fine tune the neutralization on 10m. I read this tip on one of the 
Drake user web sites.

  73,
  Bob WW3QB

  At 08:44 PM 8/28/2008, you wrote:

    A Drake technical bulletin issued when Drake could no longer get Sylvania 
6JB6s and they had to begin substituting GE brand ones, says the following:
     
    The T-4X series transmitter uses a 6 pf @ 2KV padder capacitor (C-48) 
across the neutralization capacitor (C-49). You must experiment with a small 
value capacitor across the existing padder C-48 to achieve proper 
neutralization.
     
    I have several sets of matched GE and RCA brand 6JB6s that I am having 
trouble neutralizing. Anyone have any idea what "small value capacitor" means 
in this context?
     
    TNX ES 73 DE MIKE WA3WOM K


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