I had access to a KPA1500 for one day during ARRL DX CW 2018. I found that
1500 watts into 1.5 SWR always produced a hard fault. SWR had to be 1.4 or
less on every tuner segment. The tuner had to be carefully trained in the
middle of each 20 KHz segment, that is: 010, 030, 050...right up to the
upper band edge. For some segments, I had to use the double-tap method to
get SWR low enough. In that method you tap ATU TUNE a second time, within
three seconds after tuning is completed, then it tries to find a better
match. Maybe things have gotten better in the last two years.
Dave Hachadorian, K6LL
Yuma, AZ
-----Original Message-----
From: K9MA
Sent: Thursday, March 5, 2020 10:22 AM
To: Dan
Cc: k9yc@arrl.net ; Alan M. Eshleman ; cq-contest
Subject: Re: [CQ-Contest] Elecraft KPA 1500 vs.OM 2000A
Perhaps there’s something wrong with my KPA1500. (Yes, I did RTFM.) At any
SWR above 1.5:1, according to the meter on the amp, it will usually fault
due to either high current or excessive drive power (saturation). The
“trained” ATU doesn’t always keep the SWR low enough, despite antennas which
are quite flat. I haven’t tried it, but I’m sure it would never approach
1500 W into a 3:1 SWR.
There’s nothing wrong with the supply voltage.
I’d like to know why my experience differs from others’. I’m away from home
now, but I’ll further investigate when I get back.
73,
Scott K9MA
----------
Scott Ellington
--- via iPad
On Mar 5, 2020, at 10:54 AM, Dan <w8car@buckeye-express.com> wrote:
I agree with Jim's comment. My KPA 1500 does not fold back until I reach
close to 3 to 1. I rarely use the tuner and my CC 2L 40 will cover the
whole band without using a tuner. I would imagine that certain
combinations of impedance and reactance might have an effect on the fold
back. The other elephant in the room is SWR being read on meters is not
always what it seems. My Daiwa, KPA 1500 and K3 (running bare foot so not
into amp input) can all have different SWR readings on the same frequency.
Dan W8CAR
-----Original Message----- From: Alan M. Eshleman
Sent: Wednesday, March 4, 2020 12:48 PM
To: k9yc@arrl.net
Cc: cq-contest
Subject: Re: [CQ-Contest] Elecraft KPA 1500 vs.OM 2000A
that's been my experience with my KPA1500...
----- Original Message -----
From: Jim Brown <k9yc@audiosystemsgroup.com>
To: cq-contest <cq-contest@contesting.com>
Sent: Tue, 03 Mar 2020 17:57:05 -0800 (PST)
Subject: Re: [CQ-Contest] Elecraft KPA 1500 vs.OM 2000A
On 3/3/2020 10:13 AM, Edward Sawyer wrote:
super SWR sensitive doesn’t sound like good characteristics for an amp.
I have NOT experienced SWR sensitivity with reasonable antennas that the
KPA1500's built-in tuner can't handle. I suspect someone having this
problem has not RTFM, which describes how to train the tuner for each
antenna for each band, or has not taken the time to do it.
The KPA1500 can memorize settings for three different antennas for each
band for each of the two antenna ports.
And I DO get pretty close to 1.5kW on 6M.
73, Jim K9YC
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
|