[Elecraft] K1-4 Low power output only on 15 meters.

[Mike Morrow]

Jim / W1FMR wrote:

> The 26.050 crystal was replaced with the kit supplied 29.000 MHz
> crystal for 15m and the K1 realigned on all bands.
>
> All seemed to go well with the receive and transmit alignment
> with the power level set to 2 watts per the manual.
>
> However now the power will not go above 2 watts on 15m..

Jim, were you *ever* able to maximize 15m power during transmitter
alignment (KFL1-4 manual page 19) *above* 2 watts?  During alignment
the power must be peaked, likely several times, well above 2 watts.

The alignment procedure has you select the desired power level during
alignment to 2 watts to set the maximum power that will exist *only at
the start* of the capacitor adjustments for that band. After a couple
of seconds of being in TUNE, ALC is no longer altered by the MPU as
power output changes.  The power level should go well above 2 watts
as you peak the capacitor settings, possibly to the point where other
physical effects are limiting the output power.  That would make it
difficult to accurately peak the filter board adjustments.  In that
event the manual has you exit TUNE, then re-enter TUNE.  That resets
the ALC to lower the max power to 2 watts.  A couple of seconds later
the ALC will remain constant, even as the power again rises well above
2 watts as you resume peaking the filter board capacitors.  Repeat as
necessary.

I'm pretty sure that you are well aware of all that.  But it almost
sounds like the peaking adjustment for 15m was halted the first
time the 2 watts level was reached.  If that happened, you will need
to go back and re-perform the transmitter alignment on KFL1-4 manual
page 19 for 15m, followed by 20m.  It would likely be worthwhile to
do that anyway, since it's such an easy process.

> The K1 display reads 5.0 when being set with buttons but
> the K1 power output display reads only around 2.1 or so
> watts.

For which the simplest explanation is that the capacitors for 15m
never got peaked to produce any higher power level.  The ALC wants
to set 15m power to 5 watts, but the (mis)alignment is not permitting
levels above 2.1 watts to be reached.

That's my best guess.

73,
Mike / KK5F