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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