[Elecraft] KXPA Power Output

[Tom Field]

Thanks for the replies.
I have gone through the procedure again.
I used the calibration procedure outlined on the Elecraft Website.


Some observations. With no load I have 14.63 volts coming into the KXPA
100.
With the radio and amplifier on and resting, the current is approx 0.3 Amps

Steps
Set the radio in the 160 meter band
Set P Cal
Closed the menu
Set Pwr to CAL 75
Confirmed the KXPA 100 Is in bypass
Pressed Tune( I assume this is the button that says transmit)
Current rose to .9 Amps
If I took the pressure off the button, the current stayed up until I
pressed it again
The display showed 2 numbers  On top 1.1  Below 5.0
Pressed the button again
Normal Display returned
Moved on to 80 meter band
Same behaviour and findings
Moved to 60 meter band
Same
40 meters, 30 meters, 20 meters same with approximately same current
17 meters, Current went up to 1.21 Amps
15 meters 1.24 Amps
12 meters 1.45 Amps
10 meters 1.45 Amps
6 meters
Display showed 3 instead of 5 and 1.68 amps

Opened the menue and turned the PA to on

Set the PA back to auto

set power at 75 Watts
Using the KXPA Utility
                            Input Power                  Forward Power
160 m                         0.8                                48
80 m                           1.0                                50
60 m                           1.2                                52
40 m                           1.2                                51.4
30 m                           1.1                                56.8
20 m                           1.6                                59.2
17 m                           1.6                                82
15 m                           1.2                                51
12 m                           1.0                                49.5
10 m                           1.2                                50.3
6 m                             2.0                                60.6

The only band that came close was 17 meters. I wonder if there is something
about the calibration process. Accd to the notes from the Elecraft website
"Press TUNE. The KX3 will transmit for a short while then stop. During this
transmission, the KX3 and KXPA100 will determine what drive level is needed
to get to 75 watts"

I found if I pushed and held TUNE, it started transmitting and did not stop
transmitting until I let off and pushed it again.

Advice, suggestions welcome.

Tom
KN6DR


On Sat, Apr 16, 2016 at 5:29 PM, Tom Field <docwatt at gmail.com> wrote:

> I'm having difficulty getting more than about 70 to 80 watts out of the
> KXPA 100. I have it connected to a KX3 with the Elecraft cable and have
> gone through the calibration procedure as outlined in the owners manual and
> in Fred Cady's excellent book.
>
> For Example if I go through the calibration procedure on 40 meters,
> It appears to show a drive level of 5 watts to achieve 75 watt output.
> If I transmit into a dummy load, with the power setting at 100 watts,
> I have a drive power of about 2.6 watts and an output power of about 70
> watts as shown in the KXPA Utility.
>
> Am I missing something?
>
> Tom
> KN6DR
>