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

[Eric Swartz - WA6HHQ, Elecraft]

The KPA500 has in internal 3 dB attenuator in the drive path that will 
be switched in automatically by the amp in cases of overdrive.

73, Eric  WA6HHQ
===

On 4/21/2010 10:44 AM, Doug Faunt N6TQS +1-510-655-8604 wrote:
> 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
>
>     From: Alan Bloom<n1al at cds1.net>
>     Date: Wed, 21 Apr 2010 10:32:18 -0700
>
>     On Wed, 2010-04-21 at 12:23 -0400, 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.
>
>