[Elecraft] KPA500

[Jack Brindle]

Walter;

You don't mention what radio you are using with the KPA500. If it is the K3, do you have ALC turned on in the K3? And, do you have the KPA500's ALC output connected to the radio's ALC input pin? Also remember that the ALC setting does not affect KPA500 power, but rather radio output power. We do not recommend its use with the K3.

The ALC setting corresponds to a threshold value. When the exciter's output exceeds the threshold, the KPA500's ALC output will decrease (it goes from 0 to -12V) in order to reduce transmitter power. At a setting of 210 the transmitter's power level pretty much will not be affected, while at 0 the transmitter will not be putting out any power.

Having said all this, I will also add that the use of ALC with ham amplifiers is very argumentative. Proper adjustment of the transmitter will eliminate the need. With the K3's power settings for the KPA500 along with its design, you should never need it.

Jack Brindle, W6FB


On Oct 29, 2011, at 8:23 AM, walter renner wrote:

> I have KPA500 #429, and I really love the amp, but have been confused by the ALC threshold settings. 
> 
> Maybe someone on  this list can help me with a question I have concerning what it operation.
> 
> The ALC settings are from 0 to 210, and I find that it has no effect on power out regardless of where I set ALC.
> The power out remains the same whatever the settings.  Nothing changes from 0 to 210 on power out. Any ideas setting has the least effect on 
> power out or what setting has the most effect.
> 
> 
> Kurt    K0ARO
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