[Elecraft] KX3 2M External amp -- go linear!

[Edward R Cole]

Joel and all:

The 80w amplifier I build is the Klitzing amp described, below.

I purchase the unpopulated pc board from Jim and order all other 
components.  I install them in  Hammond enclosure with same heat sink 
Jim recommends, plus a 120mm square fan controlled by a 
thermistor-based ckt.  I also add a bar meter which indicates 
relative output.  I also use the ALC kit from Jim to sample RF power 
for the meter.

It runs with 8amp quiescent current at near class-A operation so very 
linear in output.  No preamp is included but the TR relay allows 
bypass in OFF so you do not need to disconnect the amp if not 
needed.  I agree with Joel that there are better preamps than 
typically embedded in most ham VHF amps.

I handle PayPal sales for the popular WA2ODO preamps (6m-13cm).

73, Ed - KL7UW


snipped-----------------
I convinced Jim to design and build an amplifier that would make my K3
competitive with the typical 100 W HF-VHF transceivers. With my great
receiver and 10 W transmitter, I was hearing people and they weren't hearing
me. By staying at the 100 W level, I could use the same power supply that my
K3 used for HF. I have been using the amplifier for years and been very
happy with it. It is very linear up to 80 W PEP out on SSB, but happy to do
CW and FM at 100 W. See the article at:

May 2013 -- QST (p. 30)
Build a Linear 2 Meter 80 W All Mode Amplifier


Jim offers PC boards, unpopulated, as well as largely complete, for
reasonable prices via his web page at w6pql.com. This amplifier is the size
of a brick, probably costs less and is a much better product, in my view. I
recommend it without reservation.

Regards, Joel Hallas, W1ZR
Westport, CT


73, Ed - KL7UW
http://www.kl7uw.com
     "Kits made by KL7UW"
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