K3s - 80W on 160 - Resolved

At my station I use a large 70 amp Astron power supply which sits on the
floor.  Several month ago, while trouble shooting another issue, I
discovered that the voltage drop in my 8' cables was significant. So
rather than crank up the voltage I switched to 8ga and now at full
transmit wattage the K3S sees 13.5v. The tough part was squeezing 8ga wire
into a PowerPole connector that is made for 10ga max. For a shorter lead,
like I use when I travel to the Caribbean, 10ga has a minimal voltage
drop.

John KK9A

From: Gary Smith ka1j

Hi Jim & the others who replied,

This is a follow-up for someone in the
future who looks for the same solution.

Yeah, the small amount of difference in
the wattage is insignificant but
considering all the radios I've owned, the
low end of the bands were always the
highest output. 10M was usually the lowest
output & with the K3/K3s, 6M was always as
good as the other bands watt wise and 160
was full output. This not being the case,
I was concerned.

I had done the calibration and raised the
output to 87W but that was it. As was
suggested, I raised the voltage from the
PS to give me 13.8V on transmit which
required 14.6V resting. I'm using the
cable Elecraft supplies and I'm suspecting
it could be just a tad lower gauge/thicker
copper to reduce the resistance but on
160M, I am now getting a 115W reading on
the P3 and 113W on the LP-100A.

So the increased voltage was the
difference in my case. A thicker wire
would certainly require less voltage than
14.6 and that's what I am going to look
into. With the power Pole connector, I'll
have to look a little deeper into what
will work best. I have no crimping tool
for Power Pole so that makes it more of a
challenge.

Anyway, thanks Jim & all who suggested the
higher voltage, it was the answer in this
instance.

73,

Gary
KA1J

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[Charlie T, K3ICH]

A possible solution is to use the heaviest wire you want from the power
supply to a few inches away from the radio with a very short pair of 12 ga.
wires from the APP to the heavy wire.
 Shrink tubing can make an ugly connection look passable.  It's BEHIND the
radio anyway!

73, Charlie k3ICH


Subject: [Elecraft] K3s - 80W on 160 - Resolved

At my station I use a large 70 amp Astron power supply which sits on the
floor.  Several month ago, while trouble shooting another issue, I
discovered that the voltage drop in my 8' cables was significant. So rather
than crank up the voltage I switched to 8ga and now at full transmit wattage
the K3S sees 13.5v. The tough part was squeezing 8ga wire into a PowerPole
connector that is made for 10ga max. For a shorter lead, like I use when I
travel to the Caribbean, 10ga has a minimal voltage drop.

John KK9A



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[Guy Olinger K2AV]

One does not need to jam too-large cable into the power pole connector. Do
the power pole normally with the #10 zip cord. Then two or three inches
away from the power pole, splice in two more parallel runs of the #10 zip
cord. Solder and tape these splices.

This will divide your voltage drop by three. 14.6 at PS can be 14.3 at K3,
better for TX IMD.

The IR loss is spread along the entire wire. A few inches of single #10 to
service the connector will not make any difference.

Another approach is to fasten down a length of #4 - 3 plus ground "Romex"
cable. You can get this stuff cut to exact length at the big box store. At
either end terminate with soldered splices to a few inches of #10 zip cord.
Black and green to black, red and white to red. That will allow you to put
PS anywhere you want. You do need a pretty permanent placement of equipment
for this.

73, Guy.

On Wednesday, December 21, 2016, [hidden email] <[hidden email]> wrote:

> At my station I use a large 70 amp Astron power supply which sits on the
> floor.  Several month ago, while trouble shooting another issue, I
> discovered that the voltage drop in my 8' cables was significant. So
> rather than crank up the voltage I switched to 8ga and now at full
> transmit wattage the K3S sees 13.5v. The tough part was squeezing 8ga wire
> into a PowerPole connector that is made for 10ga max. For a shorter lead,
> like I use when I travel to the Caribbean, 10ga has a minimal voltage
> drop.
>
> John KK9A
>
> From: Gary Smith ka1j
>
> Hi Jim & the others who replied,
>
> This is a follow-up for someone in the
> future who looks for the same solution.
>
> Yeah, the small amount of difference in
> the wattage is insignificant but
> considering all the radios I've owned, the
> low end of the bands were always the
> highest output. 10M was usually the lowest
> output & with the K3/K3s, 6M was always as
> good as the other bands watt wise and 160
> was full output. This not being the case,
> I was concerned.
>
> I had done the calibration and raised the
> output to 87W but that was it. As was
> suggested, I raised the voltage from the
> PS to give me 13.8V on transmit which
> required 14.6V resting. I'm using the
> cable Elecraft supplies and I'm suspecting
> it could be just a tad lower gauge/thicker
> copper to reduce the resistance but on
> 160M, I am now getting a 115W reading on
> the P3 and 113W on the LP-100A.
>
> So the increased voltage was the
> difference in my case. A thicker wire
> would certainly require less voltage than
> 14.6 and that's what I am going to look
> into. With the power Pole connector, I'll
> have to look a little deeper into what
> will work best. I have no crimping tool
> for Power Pole so that makes it more of a
> challenge.
>
> Anyway, thanks Jim & all who suggested the
> higher voltage, it was the answer in this
> instance.
>
> 73,
>
> Gary
> KA1J
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email] <javascript:;>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email] <javascript:;>
>

--
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