http://elecraft.85.s1.nabble.com/KPA-1500-tuner-questions-tp7649648p7649661.html
Just a general comment on the KPA1500: My experience with it shows that the SWR has to be below 1.2:1 at the amplifier output (ATU input) to run reliably at full power. If the SWR is higher than that, the amp will often fault due to excessive current or drive power before reaching 1500 W. (And may splatter on SSB.) Elecraft recently updated the ATU firmware to consistently find a better match, and it really helps.
> On Mar 11, 2019, at 8:49 PM, Peter Dougherty <
[hidden email]> wrote:
>
> I have a couple of questions about the KPA1500's internal tuner.
>
> For the most part, I leave the tuner inline. Except for two sub-bands (SSB
> on both 40 and 80m) I am well below 2:1, and maybe 2.5:1 at the top end of
> 160m. The KPA does a good job throughout.
>
> The problems/questions arise when I need to transition between the KPA's
> internal tuner on the bottom ends of both 40 and 80, and the external
> Palstar HF-Auto tuner, which I need to wrangle very high SWRs on the phone
> portions of those bands. Obviously I don't want both automatic tuners inline
> at the same time. The situation is most acute on 40.
>
> The HF-Auto (external automatic tuner) is bypassed everywhere except the
> range of 3650 to 4000, and 7100 to 7300. I would like to automatically have
> the KPA1500's tuner go into bypass at the above ranges, just as the Palstar
> auto-tuner bypasses outside of those ranges. Is this somehow possible, or
> must I manually switch the tuner in and out when I cross the appropriate
> thresholds?
>
> Second question, and I think this relates to the whole "bins" thing, which I
> don't understand, relates to having different tuning solutions on the same
> band segment. This could be handy for me on 80m. Unlike on 40, for 80 I have
> an inverted vee, and it's easy for me to drop the ends and change the length
> of the antenna, so that instead of being resonant at 3550 I could make it
> 3700. I did this for the ARRL-SSB contest and it worked pretty well. Is it
> possible to have two different sets of memorized tuning solutions in the
> KPA-1500, in the event I have the vee set for CW (normal) or SSB (for phone
> contests only)?
>
>
> ---------------------------------------------
> 73 and Good DX
> Peter, W2IRT
>
>
>
> President, North Jersey DX Association
>
> DXCC Card Checker
> Letter O Manager, ARRL Incoming 2nd District QSL bureau
>
>
>
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