Re: KPA-100 Power control unstable on 40M

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Re: KPA-100 Power control unstable on 40M

William Shappley

> Steve -
>
> Much obliged.  I tried the mod you addressed and that has settled  
> it down.  Just a slight overshoot when set at 100W.  More
> when running lower (25W), but not as bad and I don't really care  
> since the KPA-100 has plenty
> of headroom down there.  I used the 1K and 3.3K values on the KSB  
> board as recommended.
>
> 73,
> Bill
> K4DXU
>
> Original reply:
>
> Bill:
>
> It could be the problem I and some others had, where
> there was a bit too much gain through the transmit
> chain when the KPA-100 is installed for the ALC to
> maintain control (in my case it was worst on 80m).
> Here is a link to my "problem solved" post, which also
> links to my original problem post.  I can probably
> root around and find some off-list correspondence I
> had on this subject if you would like more info.
>

> <snip>
>

> I believe there has been at least one case of similar
> symptoms that were not fixed by the cure I used,
> however.
>
> 73,
> Steve VE3SMA
>
> Original Message:
>
> <snip>
>
> Anyway, I am seeing unstable power control on 40M SSB. 40M CW seems  
> fine (although the power control "hunts"
> a little more than it does on the other bands). The power output on  
> my peak reading Bird
> will exceed 150W on voice peaks - on the other bands, the peak is  
> at or below the power control setting.
> Input current hits about 20 amps (normally it is pulling about 15  
> amps, except
>
> <snip>
>

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