[Elecraft] Issue 12 re Astron Power Supply

[Wes Stewart]

Unfortunately, the IMD can be unacceptable even with the supply set to the high 
side.

I will confess to not having measured IMD v. supply voltage.  For my manual 
method, that entails another layer of data.  I have however, characterized my 
old K3 and my new K3S with three different LPAs and four HPAs, with frequency 
and output power as variables.  I suspect that most would be surprised to know 
that there is significant variation over frequency; more than with respect to 
power.

My K3s in its latest reincarnation KLPA3A Rev B3, KPA3A Rev C9, has exceptional 
IMD of -42 dBc at 40 meters and unacceptable IMD of -22 dBc at 10 meters and 10 
W output.  Same radio, power supply and measurement system.  The only variable: 
frequency.

Wes  N7WS

On 4/17/2018 6:31 PM, Bob wrote:
> I think the original question has morphed.  It is really two questions. The 
> operational range of the K3 as one.  The second is really the optimum range of 
> the K3.  In dealing with the drops between the K3 and power supply how much is 
> excessive?   My Astron is set for 14 volt and drops at the K3 under XMIT.  How 
> much drop would be necessary for the IMD to rise to  an unacceptable level? Or 
> put another way what is a reasonable goal for the drop in the power cable or 
> power distribution to the K3?
>
> Zero millivolts would be ideal but not obtainable.  I'll admit to not having 
> the knowledge or test gear to measure the IMD. If instead of getting 100 watts 
> I could only get 95 watts to me that would be insignificant.  But I don't want 
> to XMIT a "dirty" signal either.
>
> 73,
> Bob
> K2TK  ex KN2TKR (1956) & K2TKR