Chris -
I built up the KPA-100 / KAT-100 combo earlier this year. I second
Don's comments, and have a few more:
Build and test the KAT-100 first. Get the KAT-100-2 version which has
the larger enclosure.
If you are installing the KAT-100 and the KPA-100 in a separate
enclosure, and will always have them assembled this way, then there are
a few things that can be omitted when building the KPA-100.
Specifically, the internal RF cable that goes from the KPA-100 board to
the K2 main board. This function will be provided by the BNC-BNC cable
mentioned below.
The multi-colored control cable will reach between the proper connectors
in the amp and tuner without modification. Same for all other
interconnects.
I also skipped the steps involving mounting of the speaker on the
KPA-100. Since I was going to leave the K2 pretty much "stock", I chose
to leave the K2 speaker in place. As in the RF cable (above), this
means that the cables and connectors intended to bring speaker audio to
the KPA-100 mounted speaker are unnecessary, and may be omitted. You
end up with a "spare" speaker this way, which may be useful for some
other project. Same for installing the magnetic shield on the speaker.
I covered the hole (in the KPA-100 heatsink) that would have existed
because of the not-used speaker with some scrap plastic, painted flat
black. Glued it in place with RTV cement (bathroom sealer).
Do take Don's advice and get the KIO2 module.
Remember that the antenna switch and power level indicators on the
KAT-100 will not operate properly unless the high-power 12-volt source
for the KPA-100 / KAT-100-2 is on before the K2 is powered up. I think
you can do them simultaneously, but have not tried this.
I decided, after reading about the use of transistor thermal pads and
the need for re-tightening the mounting screws periodically, that I
would try the use of semiconductor thermal grease instead. This is a
white compound commonly sold as "heat sink compound", and is available
from Mouser electronics, among other vendors. I think it is a mix of
silicon grease and zinc-oxide. It might even be available from Radio
Shack. Hopefully, this compound, while somewhat messy to apply, will
make re-tightening the screws unnecessary. If you decide to use it,
remember a little goes a long way, and be sure the counting surface of
the transistor is evenly and completely covered with a _thin_ layer.
Any excess will squeeze out of the way when the mounting screws are
properly torqued. I have used this stuff for years and years, and never
had a failure attributable to lack of thermal contact between the active
device and whatever heat-sink was being used.
Good luck with your upgrade!
- Jim, KL7CC
Don Wilhelm wrote:
Chris,
Installing the KPA100 and KAT100 together in an EC2 enclosure is
really easy. Order the KAT100-2 and you will have all the components
needed to connect the KPA100 into the KAT100 board. You will need a
cable to connect from the KIO2 to the KPA100 (or the KAT100) DE9 AUX
I/O connections - the materials needed are provided with the KAT100
kit. In addition, you will need a short piece of coax with BNCs to
connect from the K2 antenna output to the KAT100 AUX RF input.
Another short piece of coax with PL259s is needed to connect from the
KPA100 RF output to the KAT100 ANT IN. If you already have the KAT2
installed in your K2, it can stay - when the K2 determines the KPA100
is connected it bypasses the KAT2 and provides RF on the KAT2 ANT1
connector.
_______________________________________________
Elecraft mailing list
Post to: [email protected]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
