K2/KPA100

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K2/KPA100

Larry Dodson-2
I have started to experience low power on 12 and 10 meters with my KPA100. I
get 65 watts on 12 meters with a good SWR (1:1) and 35 on 10 meters with a
good SWR (1:1).  I initially thought of the low pass filters in the KPA100
but the schematic shows that this would affect 15 meters as well, and 15
meters give out a good 100 watts.  The K2 alone into a dummy load is good:
12-14 watts on all bands, except with 10 watts on 12 meters and 8 watts on
10 meters; which if I remember right is correct. Any advice will be
appreciated.

Larry (G0IKE) K2 - 2424
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Re: K2/KPA100

Bill Coleman-2

On May 11, 2010, at 4:56 PM, Larry Dodson wrote:

> I have started to experience low power on 12 and 10 meters with my KPA100. I
> get 65 watts on 12 meters with a good SWR (1:1) and 35 on 10 meters with a
> good SWR (1:1).  I initially thought of the low pass filters in the KPA100
> but the schematic shows that this would affect 15 meters as well, and 15
> meters give out a good 100 watts.  The K2 alone into a dummy load is good:
> 12-14 watts on all bands, except with 10 watts on 12 meters and 8 watts on
> 10 meters; which if I remember right is correct. Any advice will be
> appreciated.

The K2 ought to be able to put out a solid 10 watts on 10m, and at least 12 watts on 12m with no problem. I would check the archives for troubleshooting low output on 12/10m. There are some build details having to do with the transmit transformers that may need to be followed to get full output on 10m.

The KPA100 should have more than enough gain on 10m to produce a full 100 watts. My K2/100 can barely make 10 watts across the whole 10m band with the KPA100 disabled, but has no problem producing 100 watts with the KPA100 enabled.

I would start with the low output on the base K2, and work from there,

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

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