KX1 Low power output

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KX1 Low power output

ae5ka
With 13.0 volts at the input jack (from a bench supply), and 12.7 volts on
the circuit board's + bus, I am only reading 1.4 watts maximum power output
into a 50 ohm dummy load. I haven't found a problem using the
troubleshooting guide, voltages at Q1, Q4, Q5, and Q6 are where they are
supposed to be. T1 and L3 look OK to me - but if I'm a sub-par winder can
that lead to lower output?

I have the resistors for the higher power output mod, but I'm trying to rule
out build problems first.

Any additional ideas?

Thanks,
Chip
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Low power output

ae5ka
With 13.0 volts at the input jack (from a bench supply), and 12.7 volts on the circuit board's + bus, I am only reading 1.4 watts maximum power output into a 50 ohm dummy load. I haven't found a problem using the troubleshooting guide, voltages at Q1, Q4, Q5, and Q6 are where they are supposed to be. T1 and L3 look OK to me - but if I'm a sub-par winder can that lead to lower output?

I have the resistors for the higher power output mod, but I'm trying to rule out build problems first.

Any additional ideas?

Thanks,
Chip
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Re: Low power output

Don Wilhelm-4
  Chip,

What tools do you have available for measuring RF voltage?  RF Probe,
oscilloscope with 10X probe?, or none.
How certain are you that your reference wattmeter is correct?  Many can
be in error by as much as 20% of the full scale reading.  On a 20 watt
scale, that is 4 watts - not very good when measuring QRP levels.

I am not saying you do not have a problem, but if I am to help, I need
to know the details about how you are doing the measurements.

Do you have the KXB3080 installed?

Please let me know your tools for measuring RF voltage and I can guide
you further.  If you have none, are you willing to build an RF probe?

73,
Don W3FPR


On 12/26/2010 6:47 PM, ae5ka wrote:

> With 13.0 volts at the input jack (from a bench supply), and 12.7 volts on
> the circuit board's + bus, I am only reading 1.4 watts maximum power output
> into a 50 ohm dummy load. I haven't found a problem using the
> troubleshooting guide, voltages at Q1, Q4, Q5, and Q6 are where they are
> supposed to be. T1 and L3 look OK to me - but if I'm a sub-par winder can
> that lead to lower output?
>
> I have the resistors for the higher power output mod, but I'm trying to rule
> out build problems first.
>
> Any additional ideas?
>
> Thanks,
> Chip
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Please help support this email list: http://www.qsl.net/donate.html