[CQ-Contest] Elecraft KPA 1500 vs.OM 2000A

K9MA k9ma at sdellington.us
Thu Mar 5 12:22:45 EST 2020


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 at 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 at 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 at audiosystemsgroup.com>
> To: cq-contest <cq-contest at 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
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