Low Power on 160

[I7SWX]

Hi Phil,

I believe you have the 10W K3.

While testing the replacement of 1st mixer on main RX with a 2T H-Mode Mixer on a K3, following the TX calibration routine, all positive from 1.8 to 50MHz, on the 100W PA, (5W and 50W routine) while testing each band on a dummy load at full power, we discovered that on 80m we could not go more than 65W, while all the other bands were at least 100W RF out.

Maybe you have the same problem as us. We believe there could be a wrong component in the Low Pass Filter, maybe a coil or a capacitor or both.

The K3 RF Board Appendix B circuit diagram does not report components value for the Low Pass Filters. We have requested Elecraft support for components data so we can check if there maybe a wrong component(s) assembled. The K3 owner, IZ8DBJ, never used 80 and 160m bands so he could not discover that when purchased. This is K3 S/N 01757.

If there is a wrong component assembled the repair will be very easy.

73

Gian
I7SWX




Message: 8
Date: Tue, 06 Dec 2011 09:43:36 -0500
From: Phil Theis <[hidden email]>
Subject: [Elecraft] Low Power on 160
To: "[hidden email]" <[hidden email]>
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

All bands produce full power except 160 meters.
K3 (352) into a Bird dummy load
When I tap TUNE the power is 7 watts.
When I increase the power knob the reading indicates increase in power,
but no actual power increase, then after a second the reading returns to
7 watts.
I hope there is something simple that I am missing.
Thanks for help.
73,
Phil K3TUF
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