[Elecraft] K3s - 80W on 160 - Resolved

[John Kaufmann]

I use a 6-foot run of 10 gauge cable between my power supply (the Astron
RS-35M) and my K3S.  With my Fluke DVM, I measured the voltage difference
between the power supply output terminals and the Power Pole terminals
inside the radio.  The difference is only .03 or .04 volts under maximum
current draw when transmitting at full power.  In other words, the voltage
drop across the entire length of the 10 gauge cable is negligible.  There is
no benefit to using a large gauge wire unless you are using a really long
(>> 6 feet) cable.

 

73, John W1FV

 

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Date: Tue, 20 Dec 2016 17:34:59 -0500

From: "Gary Smith" <Gary at ka1j.com>

To: jim at audiosystemsgroup.com

Cc: Elecraft at mailman.qth.net

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

Message-ID: <5859B213.5783.6C3A360 at Gary.ka1j.com>

Content-Type: text/plain; charset=US-ASCII

 

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