KPA 100 Power requirements

[Stephen W. Kercel]

I am considering the purchase of a K2 kit with the 100 watt amplifier. I
have several questions about power requirements:

Is the Astron RS-35 series adequate to power the 100 watt version of the
transceiver? (I'm sure it supplies enough current. I was wondering if the
ripple and regulation are adequate.)

I would like to put a circuit breaker between the power supply and the
transceiver. Does anyone have any recommendations as to current rating and
operating speed? Preferably, is there a specific manufacturer and model
that is considered best suited to the task? Is a circuit breaker actually
necessary, or am I simply succumbing to the temptation to gild the lily? I
am considering a Potter and Brumfield W31-X2M1G-25, but I wonder if it
might be too slow.

I am also thinking to install an EMI filter between the power supply and
the transceiver. The one I have in mind is the Spectrum Control 54-848-005,
rated at 50 amps and with an insertion loss of 30 dB at 3 MHz. (The down
side is that the filter costs a bit over $100.) Is this a good idea, or am
I attempting to solve a problem that does not arise in the K-2/KPA100.

What kind of power connector do I need to make up the high power DC
connection to the K-2?

Thanks and 73,

Steve Kercel
AA4AK






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[Brian Mury-3]

On Sun, 2005-02-01 at 18:44 -0500, Stephen W. Kercel wrote:
> Is the Astron RS-35 series adequate to power the 100 watt version of the
> transceiver? (I'm sure it supplies enough current. I was wondering if the
> ripple and regulation are adequate.)

It is more than adequate. Ripple and regulation are fine. The Astron
linear supplies are very good. I'm using an RS-20A with my K2/100, BTW.

> Is a circuit breaker actually
> necessary, or am I simply succumbing to the temptation to gild the lily?

The KPA100 comes with a fuse holder and fuse that you install in the
power line during construction. This should provide all the protection
you need. I suppose you could use a circuit breaker instead, but I don't
see any real advantage.

> I am also thinking to install an EMI filter between the power supply and
> the transceiver. Is this a good idea, or am
> I attempting to solve a problem that does not arise in the K-2/KPA100.

I wouldn't worry about it unless you suffer from noise that is getting
in via the power cable.

> What kind of power connector do I need to make up the high power DC
> connection to the K-2?

The KPA100 has a PowerPole connector on the back. The kit includes a
power cable, a PowerPole connector to put on it, and the fuse holder and
fuse I already mentioned. All you need to add is whatever you need to
connect to your power supply. With the Astron, either just stick the
bare wire ends under the nuts, or (better) use ring terminals.

--
73, Brian
VE7NGR

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[Ron D'Eau Claire-2]

Steve AA4AK asked:

Is the Astron RS-35 series adequate to power the 100 watt version of the
transceiver? (I'm sure it supplies enough current. I was wondering if the
ripple and regulation are adequate.)

-----------------------

As you suspected, it's way overkill! I use an Astron 20 to power the K2/100
and some other gear in the shack at the same time. You will normally draw
closer to 15 or 16 amps, total, at 100 watts out. It varies with the band.
Ripple and regulator are fine. The K2/100 has a 20 amp quick-blow fuse in
the power line.

With the fuse, I'd question the need for a circuit breaker or other
protection. I certainly don't use any.

Elecraft supplies the cable and connectors and in-line fuse with the KPA100
module. It uses Anderson Power-Pole connectors - 30 amp size for plenty of
reserve capacity.

Ron AC7AC



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[Stuart Rohre]

Steve, the Astron has the ratings to handle the K2 plus 100 watts.   It also
has voltage regulator that should limit the current, so added breaker is
optional.  It should be slightly larger than the current draw of the K2 plus
the amplifier, if used.

If you do not use the breaker, be sure to fuse the K2 near the supply,
although the K2 has a current limiting circuit of its own.  That is standard
safety practice in case the insulation rubs thru along the wires to the rig.
72,
Stuart
K5KVH


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[Hisashi T Fujinaka]

I have an Astron 35 and the foldback circuitry is pretty nice. I had the
two power leads that go from the KPA100 to the K2 pinched between the
shield and the side of the case, making a nice dead short. My Astron
just folded back the voltage and no fuses were wasted.

I wouldn't suggest this as a test for anyone else. :)

On Mon, 3 Jan 2005, Stuart Rohre wrote:

> Steve, the Astron has the ratings to handle the K2 plus 100 watts.   It also
> has voltage regulator that should limit the current, so added breaker is
> optional.  It should be slightly larger than the current draw of the K2 plus
> the amplifier, if used.

--
Hisashi T Fujinaka - [hidden email]
BSEE(6/86) + BSChem(3/95) + BAEnglish(8/95) + MSCS(8/03) + $2.50 = latte
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