[Elecraft] KXPA100 Kit Review

[Jim Sheldon]

This is mainly for those who are contemplating getting the KXPA100 to go 
along with a KX3 (with or without the PX3).

Picked my KXPA100 kit up at the UPS customer center this morning about 
9:15.  Got it home about 10:00, unpacked and inventoried by 10:30 and 
completely assembled by 11:15.  So far this is the simplest kit I've 
ever built and really worth doing to save money.  The only tools it took 
were a #1 Phillips screwdriver and a pair of needle nose pliers.

What took the longest was figuring out how to hook it up to the KX3/PX3 
combination.  Nothing in the KXPA100 assembly or Operating manuals that 
I found.  Had to go to the PX3 manual to find the information.  It might 
be a good idea for the manual writer/editor to include at least a 
reference to the PX3 manual for this configuration.  If you don't have a 
PX3, instructions for hooking everything together in the KXPA100 book is 
pretty clear.  I heartily recommend the optional cable kit and it really 
simplifies things and you don't have to spend a lot of time making 
something up to making it play nice.

Once I had everything connected and the KXPA power output display 
calibration done, I hooked it to my Alpha Delta DX-LB 160/80/40 meter 
dipole to check the tuner's capability.  It found a match on all bands 
160-6 meters and no worse than a 1.2:1 SWR so it's certainly as good as 
the tuner in the K3.

I have one of those MFJ 4230MV compact 30 amp switching power supplies 
and got everything cabled so it powers the KX3, a stereo audio speaker 
bar, PX3, KXAT100 and when needed a small clip-on LED logging light.  By 
the way, this supply is very quiet RF wise and I can't find any noise 
from it on any ham band powering either the KX3 or K3 from it (I have 
the 45 amp MFJ 4245MV supply on the K3/P3 main operating desk and it's 
quiet too).

I'm not currently planning on operating it mobile, but we're going to be 
visiting relatives in Texas, Louisiana and Florida next month so will 
have a collapsible vertical and the KX3 setup with me.  It will be nice 
to have the 100 watt amp along to help overcome poor band conditions 
when the KX3's normal output isn't quite enough to maintain a QSO.

I really like the way the firmware is set up in the KX3 and KXPA100 so 
that operation is as close to seamless as it can be.  The auto bypass of 
the internal KX3 tuner when the amp is on is really nice and the auto-on 
of the amp when the KX3 is turned on is SUPER nice!

The next project will be setting up as compact a carrying case as 
possible to safely transport the KX3, PX3, KXPA100 and all the 
accessories.

Jim - W0EB