I received my KPA-1500 yesterday (#244) and did some linearity tests today
14.2MHz, Dummy Load, ATU Bypassed. Using KPA-1500
internal Power Meter. Continuous carrier.
10W drive, Gain = 15.6dB 180W
15W drive, Gain = 15.8dB
20W drive, Gain = 15.9dB
25W drive, Gain = 16.0dB 1.0KW
30W drive, Gain = 15.9dB
35W drive, Gain = 15.7dB
40W drive, Gain = 15.6dB
43W drive, Gain = 15.4dB 1.5KW
45W drive, Gain = 15.4dB 1.57KW
Based on this it look like about .6dB compression
at 1.5KW. I think that's pretty good for an SS Amp.
I also measured the gain on all the bands at
1.5KW out. Drive varied from 31W on 80M to 47W on
15M. or 16.8dB to 15.0dB. That amount of variation is rather disappointing.
I also noted that the internal power meter is
pretty inaccurate at low levels. For Example at
50W on 20M it reads 43W. Its pretty close above
300W and right on at 1.5KW where its calibrated.
I would be interested to see any data that others have collected.
- Paul KW7Y
At 02:26 PM 6/14/2018, K9MA wrote:
The gain compression I measured, between 1000
and 1500 W on 40 meters, was 1.4 dB. I used the
K3 and KPA1500 power meters. Factory calibration of the KPA1500.
Scott K9MA
----------
Scott Ellington
--- via iPad
> On Jun 14, 2018, at 2:51 PM, Paul Baldock <p...@paulbaldock.com> wrote:
>
> What you report of compression near the
maximum power is certainly true of the
amplifiers like the SPE-1.5K that use a single
device, but I would have thought this would not
be true of the KPA1500 that uses 2 devices.
This is the reason I returned my SPE and
ordered the KPA. Hopefully the compression is less than 1dB.
>
> Has anybody else measured it?
>
> - Paul - KW7Y
>
>
>
> At 02:21 PM 6/9/2018, you wrote:
>> I recently ran a two-tone test and measured
CW power gain. (SN1078)Ã It doesn't look
good.Ã The two-tone waveform shows distinct
"flat-topping", and the power gain drops 25
percent from 1000 to 1500 Watts.Ã My old
3-500Z amplifier is much better.Ã Has anyone
measured IMD or linearity, or seen any test
results? While I'm primarily a CW operator, I'd
be very reluctant to use the amplifier on SSB.
73, Scott K9MA -- Scott K9MA
k...@sdellington.us
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