[Elecraft] K3s - 80W on 160 - Resolved

[Nr4c]

PPs solder real well. Just keep the solder off the outer portion of the round part where the wire fits. 

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...nr4c. bill


> On Dec 20, 2016, at 5:34 PM, Gary Smith <Gary at ka1j.com> wrote:
> 
> 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
> 
> 
>>> On Fri,12/16/2016 9:27 PM, Gary Smith wrote:
>>> With the ATU in or out it gives 81W out on 160, SWR is 1.28
>>> 
>>> All other bands except 6M give around 98W, 6M gives 87W
>>> 
>>> Any ideas what might be causing the lower output on 160?
>> 
>> 81W is 0.9 dB less than 100W; 87W is 0.6 dB less than 100W.  On 6M,
>> it's probably a simple matter of efficiency -- power amps are slightly
>> less efficient on 6M than on the lower bands.
>> 
>> And there may be a power calibration issue. There's a procedure in the
>> manual for doing that.
>> 
>> Or even error in the power measurement itself. Few power meters are
>> specified for better than 5%. Bird wattmeters are specified as 5% of
>> full scale, and a condition of that is that the slug is in
>> calibration. If, for example, you're using a 250W slug, accuracy is
>> +/- 12.5W. I use an N8LP LP100A, which specifies 5% at any power level
>> from 1W, and quotes 3% typical. 5% is 0.22 dB.  3% is 0.13 dB.
>> 
>> Low DC voltage can also be an issue, either due to the power supply
>> itself or IR loss in the power cable (or even the connector(s). Use
>> the built-in metering function to check DC voltage with just the RX
>> running and keydown. Short, fat copper is your friend. :)
>> 
>> 73, Jim K9YC
>> 
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> 
> 
> 
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