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Re: KPA-1500 issues

Posted by K9MA on Nov 27, 2018; 11:31pm
URL: http://elecraft.85.s1.nabble.com/KPA-1500-issues-tp7646571p7646587.html

The ATU in the K3, which should work exactly like the one in the
KPA1500, seems to consistently find a very good match, at least on the
lower bands where the L/C resolution is very good. Why the KPA1500 often
fails to find such a good match is a mystery to me. The only difference
should be the power handling capacity of the components. This would
affect strays, but I wouldn't expect them to be significant on 20 meters
and below.

73,
Scott K9MA



On 11/27/2018 14:02, Bill Johnson wrote:

> If one thinks about it, no auto tuner can be expected to get an exact match unless it is adjusted manually (that would be a PITA).  And if done manually, that doesn't mean that the match is perfect.  It just appears that way.  Consider what goes on with feedline, connections and the antenna itself.  Grounding, RF and impedance issues, etc., all can contribute to inconsistent behavior.  The Elecraft tuning is among the best for price for in rig performance IMO.  I prefer remote auto tuning myself which requires a different operation method.
>
> Now if Elecraft could design a remotely controlled, wireless preferred, tuner, I would buy one yesterday!
>
> 72 & 73,
> Bill
> K9YEQ
> FT'er for K2, KX1, KX3, KXPA100,  KAT500, W2, etc.
>
> -----Original Message-----
> From: [hidden email] <[hidden email]> On Behalf Of Paul Baldock
> Sent: Tuesday, November 27, 2018 1:39 PM
>
> There is definitely room for improvements in the tuning algorithm. Because of this I have tuned all my segments manually. I find if the SWR is not adjusted to be close to 1:1 in all segments of a band then the drive requirements vary across that band, which would be very annoying.
>
> In addition the tuner may not always be in the segment you think it is. This is due to the 8KHz resolution of the internal counter, that wins over you sending it a more accurate frequency, and also the hysteresis algorithm that can require a 2 segment frequency change before the tuner changes. Gary from Elecraft says "if you are off by one bin segment then it should not matter too much"
>
> I also note that when into a perfect 50 Ohms, and the tuner bypassed, on 6 meters, my KPA1500 says the SWR is 1.4:1. On 10 meters it reads 1.2:1.
> Rene from Elecraft says "this is the best they can do".
>
> Other than the issues above I am very happy with the KPA1500.
>
> - Paul
>
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--
Scott  K9MA

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