[RTTY] AL-80B Or KPA500 for RTTY Contesting

[john at kk9a.com]

Actually the Elecraft KPA500 will work fine into a 2:1 SWR, especially at
the 400 watt level that the W4HM prefers.  The KAT500 is a very nice
matching automatic antenna tuner that works very well with the amp and it
also provides four autoswitching antenna outputs. The Elecraft KPA500 is
completely different than the Ameritron AL-80B. One is a well designed
automatic solid state amplifier with amazing support and one is a MFJ made
manual tune tube amplifier. I certainly would not limit myself to just these
two choices.

John KK9A


To:	rtty at contesting.com
Subject:	Re: [RTTY] AL-80B Or KPA500 for RTTY Contesting
From:	"Joe Subich, W4TV" <lists at subich.com>
Date:	Thu, 4 Aug 2016 16:30:05 -0400

>
On 8/4/2016 4:02 PM, joeduerbusch wrote:
> What do you get over the AL80B for the extra money?  Solid state no
> tune-up, auto band switch and very fast QSK break-in.

But no tuner.  Unless you have very well tuned (low SWR) antennas for
every band (and all parts of the bands in which you operate) you will
need a manual tuner (losing the advantage to "no tune-up") or a high
power auto-tuner (more $$$) to make best use of the KPA500.

Don't get me wrong ... I'm an Elecraft fan but I don't know of any
solid state amplifier that will run correctly (and safely) into a
significantly (SWR >~ 1.5:1) mismatched load.  If the impedance is
low the devices will saturate (maximum current), if the impedance
is high the devices will clip (require higher voltage).  In either
case IMD and heat dissipation rise significantly.

73,

  ... Joe, W4TV