KPA500 Question

I think requiring a different drive level is normal for most amplifiers.
The K3S is the only transceiver that I have owned where the output can be
set differently for each band, which is wonderful. My KPA-500 is pretty
tolerant of SWR 2:1 or less however that may depend on the load type.  What
is your 20m antenna?

John KK9A

From: Joe Hutchens AJ8MH
 
This is a question I've been wanting to ask...

I've had a KPA500 for 4 years and I've noticed that 20 meters requires
more drive.  Most bands require 30 watts or less, but 20 requires 35-37
for 500 watts out.  In the phone portion of 20, an SWR of 1.4:1 WILL
cause a fault.  It's just real sensitive to the load on 20.  I have to
use a tuner and make sure I'm close to 1.1:1.  Works fine into a dummy
load, but high drive is still required.

I've lived with it, because I don't operate SSB very often on any band,
but lately I've been chasing NPOTA stations and find myself using 20 SSB.

I assembled the amp, and it's been like this from day one.  Anyone else
see this on 20.  Just interested.

Joe (AJ8MH)

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[AJ8MH-Radio.Joe.Hutchens]

My antenna is a TA-33-M-WARC.  It's flat around 14.150, but goes up fast
as you head toward .350.

I have an FT-950 and FTDX-3000, and both need increased drive to get me
to 500 watts.  More concerned about the fault at 1.4:1. Although the two
could be related.  Anyway, the auto tuner handles it.  Looks like .28 uH
and 62 pf switched in.  I need to check the load with my analyzer.

73,
Joe ( AJ8MH-Radio )

On 12/18/2016 10:27 AM, [hidden email] wrote:
> I think requiring a different drive level is normal for most amplifiers.
> The K3S is the only transceiver that I have owned where the output can be
> set differently for each band, which is wonderful. My KPA-500 is pretty
> tolerant of SWR 2:1 or less however that may depend on the load type.  What
> is your 20m antenna?
>
> John KK9A
>
>

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