K3: 6 meters and power output fluctuation

[K2QI]

Hello Elecrafters,

The recent SSB output power bug in FW 4.17 had me checking my K3 in all
bands.  Fortunately, the fix was quick to come with Lyle's modified beta
v4.18.  Sometimes I wonder if the boys at Aptos ever sleep.  Anyway, after
loading the revised firmware and performing a TX calibration, I went ahead
and checked output again on all bands.  The K3 was connected to an MFJ-250
Versaload that was previously checked with an analyzer.  The anomaly appears
to only affect 6 meters (52.0 MHz). In this instance, SWR is flat at 1.0:1.
By pressing the TUNE button, I start at 5 watts and proceed up to 100 watts
by turning the front panel power knob.  After reaching the 100 watt mark,
the power output reading on the K3 drops from 100 to 86 or 87 - usually
within a second or two of reaching the 100 watt level.  I can sit here and
replicate this all day.  What's interesting to note however is that the
power output on the external meter doesn't seem to drop in conjunction with
what's displayed on the K3's LCD.  I cannot verify for sure however as my
digital SWR meter is kaput.  I'm relying on an older analog meter for this
test.

Can anyone replicate this condition with their K3 on 6 meters?  It seems
like a bug in the K3's output power reading rather than a physical fold-back
on power.  It also doesn't matter if the ATU is active or bypassed.

--
73 de James K2QI
President UNARC/4U1UN
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[K2QI]

Please disregard; just had a look at the manual and max output on 6 meters
is 70-85W depending on frequency.  I assume then that the radio is
automatically dropping down to a safe output power rather than cooking at
100W.  Guess I should have checked the manual first!  My bad!

73,
James K2QI
On Fri, Nov 5, 2010 at 9:01 PM, James Sarte <[hidden email]> wrote:

> Hello Elecrafters,
>
> The recent SSB output power bug in FW 4.17 had me checking my K3 in all
> bands.  Fortunately, the fix was quick to come with Lyle's modified beta
> v4.18.  Sometimes I wonder if the boys at Aptos ever sleep.  Anyway, after
> loading the revised firmware and performing a TX calibration, I went ahead
> and checked output again on all bands.  The K3 was connected to an MFJ-250
> Versaload that was previously checked with an analyzer.  The anomaly appears
> to only affect 6 meters (52.0 MHz). In this instance, SWR is flat at 1.0:1.
> By pressing the TUNE button, I start at 5 watts and proceed up to 100 watts
> by turning the front panel power knob.  After reaching the 100 watt mark,
> the power output reading on the K3 drops from 100 to 86 or 87 - usually
> within a second or two of reaching the 100 watt level.  I can sit here and
> replicate this all day.  What's interesting to note however is that the
> power output on the external meter doesn't seem to drop in conjunction with
> what's displayed on the K3's LCD.  I cannot verify for sure however as my
> digital SWR meter is kaput.  I'm relying on an older analog meter for this
> test.
>
> Can anyone replicate this condition with their K3 on 6 meters?  It seems
> like a bug in the K3's output power reading rather than a physical fold-back
> on power.  It also doesn't matter if the ATU is active or bypassed.
>
> --
> 73 de James K2QI
> President UNARC/4U1UN
>
>

--
73 de James K2QI
President UNARC/4U1UN
______________________________________________________________
Elecraft mailing list
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html