[Elecraft] (KX1) - Question of Power Modification Timing

[Don Wilhelm]

Stan,

The information in the Power Mod instructions is correct.  SOME KX1s 
have lower power output than others due to component tolerances.  Ni 
some cases, this becomes more of a problem with the KXB3080 
installation.  I would not arbitrarily install those resistors.

Install the KXB3080 option and then test all bands using a 13.8 volt 
power source.  If you can achieve 3.5 watts on all bands, that is all 
the design point offers.  If one or two bands are lower, first try 
adjusting the spacing of the green turns on L1 and L2 to see if you can 
even out the power.

If you cannot achieve 3.5 watts on any band, then install the power mod.

I must add that the heatsinking of the KX1 and the rating of the zener 
diode in the PA stage are not designed for more than 5 watts.  If you 
are getting more than 5 watts on any band, turn R1 to a lower level to 
limit the power to 5 watts.

If you will always be operating on a voltage less than 13.8 volts 
(battery operation), you may want to install the power mod anyway.
The actual power output will depend on the power supply voltage.

73,
Don W3FPR

On 12/18/2016 6:12 PM, stan levandowski wrote:
> I'm building my second fully optioned KX1.  I built one a few years ago
> with no problem and it was great. I sold it when I bought a KX3.   I
> missed it so much I just bought myself another one.
>
> But I could use some advice because something doesn't make sense to me.
>
>
> I opened the 30/80 meter parts package and found a "Power Output
> Modification Kit" for the KX1.  It consists of two resistors:
> replacements for R11 and R30.
>
>
> I have not yet installed the "original R11 and R30" so can I just
> install these power mod resistors NOW to avoid future de-soldering?
>
>
> This sounds like a dumb question, I know, but it seems that if this has
> been a known problem for the KX1 since April 2006 (Revision B), why
> weren't the kit resistors upgraded a long time ago, or made an addendum
> to the KX1.
>
>
> Why were they in the 30/80 module kit?  What's the connection? Do the
> upgrade resistors only apply to the 30/80 mod?
>
>
> If I had not ordered the 30/80 mod, I would not have known about this
> power mod.
>
>
> 73, Stan WB2LQF
>
>
>
>
>
>
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