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




______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

[K9MA]

On 5/19/2018 20:03, Ed Gray W0SD wrote:

> 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!

This was my concern, as well, when first considering buying a solid
state amp.  (KPA-1500 is on the way.)  I want a control input on the amp
I can connect to the switch that selects antennas so the ATU will switch
between at least two sets of settings for each band.  As that didn't
seem to be forthcoming, I built a tri-band tuner box, with 6 L networks
and relays.  That gets both my tribanders down to close to 1:1 on all
bands, at least in the CW segments.  It would still be nice if the ATU
in the amp could follow the antenna selection.

BTW, I use a little toggle switch to select the tribander.  I can switch
it several times while a station is calling to determine which antenna
is better.  There's absolutely no way one could do that with a mouse. 
Maybe hot keys would work, but I like the idea that the station can
function independently of the computer, even though I use one for contests.

73,

Scott K9MA

--
Scott  K9MA

[hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]