[Elecraft] [K3] Bias Settings.

[Joe Subich, W4TV]

David, 

You will need a special RJ-45 to Foster adapter.  Add a 
1 uF capacitor in series with the hot lead of the mic 
(Pin 1 of the Elecraft connector) and connect a 3.3 - 
4.7K resistor (not critical) between the +5V pin of the 
RJ45 and pin 1 of the Foster.  


       Foster                     RJ-45
     (Elecraft)                  (Yaesu)

  Mic +  1 -----+--|(----+          1  
  PTT    2 --+  |        |          2
         3   |  +-^^^^^------------ 3  +5V
         4   |           |   +----- 4  Mic -
         5   |           +---|----- 5  Mic +
         6   +--------------------- 6  PTT
  Mic -  7 ------------------+  +-- 7  GND
  GND    8 ---------------------+   8


73, 

   ... Joe, W4TV 
 



> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of David 
> Ferrington, M0XDF
> Sent: Sunday, January 27, 2008 5:39 AM
> To: Crafters
> Subject: [Elecraft] [K3] Bias Settings.
> 
> 
> I bought the Heil Proset to go with my K3 - I'm very pleased 
> with it and
> would like to use it with my FT-857 on 2m (until I've got my 
> XV144 built).
> 
> Can anyone give me information about the bias settings of the K3?
> And possibly suggest how I go about biasing this with the 
> FT-857. I can make
> an interface cable for the RJ45 that the 857 uses (in fact 
> have already made
> one for the Heil HM10), but I'm not sure how to go about 
> biasing the Mic. In
> fact, I know little about Electret mics (some reading coming 
> up I think).
> 
> 73 de M0XDF / K3 #174, HexKey #375
> -- 
> A bit of fragrance always clings to the hand that gives the rose.
> -Chinese proverb
> 
> 
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