[Amps] Questions about Amp Supply LK-450

[R.Measures]

On Sep 12, 2004, at 7:28 AM, Keith E. Spainhour wrote:

> Hello,
> I recently purchased a Amp Supply LK-450. It seems to be a good amp, 
> with
> the exceptions of a few problems. Any help would be greatly 
> appreciated.
>
> 160m seems to have a low output, around 550 watts.

Keith -- The problem is probably being caused by the Tune-C and Load-C 
padders on 160m.  The original disk ceramic padding capacitors need to 
be replaced with RF-current-rated capacitors that are intended for 
tuned circuit applications.  note -- common 500pF and 1000pF doorknob 
caps are not intended for tuned circuit applications.  When all is 
well, you should see c. 750w-pep on 160m.

> The tuned input seems to
> have little effect on input SWR. although the input SWR is around 1.2 
> to
> 1.5. according to my MFJ analyzer.

At what power level was the SWR measurement taken?
>
> 20m seems to have a high input swr, with low output, around 500w, and 
> the
> tuned input has little to no effect  on SWR.
>
> 10m has not been installed. The schematic gives no values for C/L/C 
> for the
> tuned input pi network. The relay is not a problem, so it would seem 
> to be
> an easy task. Just add the components for the pi network, and add the 
> tap to
> the output pi network. Although the output tap may take a little trial 
> and
> error.
>
> All of the other bands seem to work fine with little or no touching up 
> of
> the tuned input.
>
>
> Thank you,
> Keith Spainhour, KT4XW
>
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>
Richard L. Measures, AG6K, 805.386.3734.  www.somis.org