K2/100 Power dither and R98

[Bill Coleman-2]

In setting up to use the K2/100 with my newly acquired AL-80A, I  
found that the K2/100 power output 'dithers' about 5-9 watts a few  
seconds after being keyed, depending on the band a power level. This  
makes it difficult to tune the amplifier, as the shifts in power  
output cause changes in Ip, Ig and power out that are unrelated to  
the tuning adjustments.

I found the technical article on adjusting for this by changing the  
value of R98. Rather than go through the complicated procedure, I  
just changed the value of R98 to 1k, then re-checked the power output.

Interestingly, before the change, the output on 10m was about 90  
watts, max. After the change to 1k, it is still about 90 watts.

The amount of dither has decreased quite a bit, but it is still  
evident enough when tuning the amplifier. I wonder if it would be OK  
to try larger values, such as 1.5 or 2 k. What's the limiting factor  
in choosing this resistor?

Bill Coleman, AA4LR, PP-ASEL        Mail: [hidden email]
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901

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[Don Wilhelm-3]

Bill,

As stated in the change documentation, the limiting factor is the power
output on 10 meters.  Change it to a higher value and see what happens.

73,
Don W3FPR

> -----Original Message-----
>
> In setting up to use the K2/100 with my newly acquired AL-80A, I
> found that the K2/100 power output 'dithers' about 5-9 watts a few
> seconds after being keyed, depending on the band a power level. This
> makes it difficult to tune the amplifier, as the shifts in power
> output cause changes in Ip, Ig and power out that are unrelated to
> the tuning adjustments.
>
> I found the technical article on adjusting for this by changing the
> value of R98. Rather than go through the complicated procedure, I
> just changed the value of R98 to 1k, then re-checked the power output.
>
> Interestingly, before the change, the output on 10m was about 90
> watts, max. After the change to 1k, it is still about 90 watts.
>
> The amount of dither has decreased quite a bit, but it is still
> evident enough when tuning the amplifier. I wonder if it would be OK
> to try larger values, such as 1.5 or 2 k. What's the limiting factor
> in choosing this resistor?
>
> Bill Coleman, AA4LR, PP-ASEL        Mail: [hidden email]
> Quote: "Not within a thousand years will man ever fly!"
>              -- Wilbur Wright, 1901
>

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