[Elecraft] Elecraft gear relative IMD

[ac5p at sbcglobal.net]

Who has some measured 2 tone IMD test figures for an actual  K3/K3S at full and reduced power levels and at supply voltage levels between 12-15 volts?Must assume the Harmonic and Spurious Outputs exceed 50dB below carrier @ 100W within ham bands as per Elecraft manual specs.  HOW  much better than 50dB with above variables is the question?   Can someone share these figures?  
73,Mike  AC5P   
 

    On Wednesday, December 30, 2015 6:39 PM, Don Wilhelm <w3fpr at embarqmail.com> wrote:
 

 I think it is time to change the subject line (and I did).  The original 
question was about increased IMD with lower power supply voltages.
It has now morphed into the relative IMD at different power levels with 
higher (normal) power supply voltages.

Whatever the actual IMD of the K3/K3S at any power level, the 
information I have heard from contesters and DXers is that the Elecraft 
gear is has lower IMD than most other transceivers.  We have heard 
testimony to that repeatedly from Field Day setups and DXpeditions where 
there are multiple transceivers operating in close proximity to other 
stations.  When station A cannot hear anything interfering when station 
B transmits, that is a good thing. Elecraft gear can do that while many 
other manufacturer's transceivers cannot say the same thing.

What we do know is that higher power supply voltages provide better IMD 
figures, and since the Elecraft gear is rated for up to 15 volts, we 
will achieve better IMD performance if the power supply is cranked up to 
provide a voltage just a bit below 15 volts.

73,
Don W3FPR

On 12/30/2015 6:52 PM, Fred Jensen wrote:
> Ummm ... I don't think that was what was suggested at all.  I read the 
> post to be an observation of a *relative* condition.  All amplifiers 
> [at least that I've ever encountered] exhibit increasing distortion 
> near their rated power limits.  I've always assumed that's why 
> distortion numbers are almost always accompanied by the power when the 
> measurements were taken.
>
> My K3/100 is a K3/10 below about 15 watts ... the 100 W amplifier 
> switches out of the circuit.  I think all that the post was trying to 
> point out is that, from 100 W downward, the distortion will decrease 
> *until* the KPA3 cuts out.  At that point, the LP amplifier/exciter is 
> near it's max power, and it's distortion will probably be higher than 
> the values from the KPA3 operating just above that power.  In any 
> case, absolute distortion from a K3/<anything> is still among the 
> lowest in the marketplace.
>

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