[Elecraft] ext ALC problem

[Howard K2HK]

Don,

The output of the K3 decreases regardless of whether it is attached to amp or not when ALC is turned on. At this point I believe the problem to be in the area of the digital I/O board. If (when) I decide to use the external ALC I will check it out. 

 

Howard

 

HK

 

 


From: w3fpr at embarqmail.com
Howard,

It sounds like the ALC voltage coming out of your amplifier is much 
greater than the K3 ALC input range.

The ALC voltage from your amplifier is reducing the K3 power output. I 
believe the problem is with the amplifier, not the K3.

Remove the ALC connection to your amplifier, then using the K3 power 
control, slowly increase the drive to your amplifier while measuring the 
voltage being developed at the amplifier's ALC output. It should be 
zero or very close to zero until the amplifier comes near its power 
limit. If the voltage at the amplifier is in excess of the ALC 
threshold you have set on the K3, then the K3 will reduce power.

In other words, if you want to set the K3 ALC Threshold at -4 volts, 
adjust the amplifier's ALC circuits to produce -4 volts when the 
amplifier's power limit is reached.

As others have pointed out, attempting to use the amp's ALC output to 
control the power output of the K3 is bad practice and is likely to 
produce distorted signals and splatter.

73,
Don W3FPR

Howard K2HK wrote:
I am having a problem with the external ALC. I am trying a new amp that requires ALC feedback. When I set it in the config menu regardless of the value -2 to -8 my output is reduced to 60 watts. As I raise the drive it increases until about 60 watts then cuts back. In the tune position which I have set for 15 watts I get only 1-2 watts out. This occurs regardless of whether I am connected to the amplifier or not. The SWR is between 1.2and 1.5. I do have the mod installed.

 

 

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