[Elecraft] Report on KPA-1500 #171 driving with a K3S

[Ed Gray W0SD]

Preliminary comments subject to learning more and operator error so FWIW.

First a few of the good things I will comment on which are just of few 
of the many good things.

KPA-1500 drives really easily.  I don't come close to needing 50 watts 
even on 10M and 6M to get 1500 watts out.  I have confirmed this is true 
using a LP-100A watt meter in addition the KPA-1500 LCD reading and LED 
reading.

Fan noise seems plenty low enough.  Of course only on SSB is it going to 
be picked up by the Microphone.  The  highest fan setting will obviously 
be on RTTY.  Using it on SSB I get good reports, ie low back ground 
noise and I see very little power out on the watt meters when not 
talking.  The true test will be in serious contest efforts but it seems 
to be fine to me.  The RF deck fan moves a lot of air in position 1 or 2

The power cord is nice and long for the 240 vac so between it and the DC 
voltage cable being reasonably long it gave me a lot of flexibility.

Instant on, instant power, no tuning, instant band changing just like 
the KPA-500. It will really be nice for higher power when needed plus I 
can use it from AZ in the winter time.

Nice having the PA temperature showing on the LCD.  When I seen 0A on 
the LCD I wondered if it was an error code.  I could not find it in the 
manual although later I did.  Once I put some power out ti was obviously 
amps!

BTW the PF1 macro I had set up in the K3S to turn the KPA500 on and of 
remotely works with the KPA-1500.  It will be pretty amazing to  operate 
the KPA-1500 at high power remotely when needed.

Basically as advertised, well worth the money IMHO.  With the devices in 
it and if the protective circuity works it should last a long, long time.

Some Concerns

SWR LED indicator flaky.(Been reported and I am sure will be fixed with 
firmware)

On SSB key up  there is sometimes power out without talking  In fact 
sometimes 200-300 watts on the LED.  Way..... less on the LP-100A watt 
meter so like the SWR LED something seems messed up. However once I say 
something it is much better so I don't think is is the microphone 
picking things up. By much better maybe 1 or 2 watts.   I don't use 
ALC.    More to be learned here but this is what I  believe I see here 
on some on the air checks.

Have what appears to be RF getting into the LCD meter on 12M on CW but 
very little on SSB.  No problem with this on any other bands.  If I turn 
the power down to about 800 watts out on CW it goes away. Things are 
missing and scrambled on the LCD read out. SWR/Reflected power is low on 
12M.  About 1.3 to 1.  It works OK looking at the Utility program so it 
just seems to be RF messing up the LCD meter.

ATU is great for stations with one antenna per band or less or even for 
more than one antenna such as for DXing.  It does not do the job for 
contesting with multiple antenna's per band if they have some SWR.  It 
is not a problem if the SWR is low then you can just use BYP   Wayne 
says this will eventually be addressed via firmware.  Until that happens 
I need to do some antenna work outside so I have low SWR for contesting 
with multiple antenna's per band.  This is always better anyway.  The 
ATU will retune on the "FLY" but to me does not seem useable for contest 
switching of antenna's, way to slow,  if there are significant SWR 
differences.   For me It will depend on the firmware fixes and how they 
are implemented.  My solution will be to do some antenna work this 
summer..  I could get by with tube type amplifiers but with SS not so much!

Ed W0SD