[Elecraft] attenuator in amp was Re: K3 and Expert 1K-FA

[Doug Faunt N6TQS +1-510-655-8604]

Probably the biggest issue is getting rid of the 70 watts of added
heat.  If there's someplace in the exiting airstream to put these
resistors.... 

73, doug

   From: "David Cutter" <d.cutter at ntlworld.com>
   Date: Wed, 21 Apr 2010 18:54:21 +0100

   T0-220 style power film resistors are fairly cheap and can easily be mounted 
   on heat-sinking surfaces.

   David
   G3UNA


   > Hm, I wonder if the KPA500 has or can have provision for this.  That
   > amp can be driven to full output by 30 watts or so, IIRC.  With the K3
   > (or K2), power control could be done automatically by having the amp
   > tell the radio that it's active over the serial interface, but it's
   > clear the KPA500 has much provision for being used with radios other
   > than the K3.
   >
   > 73, doug
   >
   Tom W8JI wrote:
   >
   >   > The correct approach would be an
   >   > attenuator pad so the radio could run at near full power and
   >   > not have a chance of overdriving the amp, ...
   >
   >   I don't understand why more people don't do that.  For example, a 3 dB
   >   attenuator between the transceiver and amplifier ensures that a 100W
   >   exciter won't overdrive an amplifier that requires 50W of drive.  The 3
   >   dB loss on receive is hardly ever an issue but if you're worried about
   >   it, just put the attenuator inside the amplifier, after the T/R relay.
   >
   >   Seems like a simple, foolproof solution.
   >
   >