[Elecraft] KPA-1500 ATU operation

[K9MA]

I understand that the ATU uses 10 kHz segments on 80, which was at some 
point changed from 20 kHz. That means the center points are 3505, 3515, 
etc. There is some hysteresis when tuning, but I'm not sure that 
consistently explains where it switches. It also won't switch until you 
stop tuning for 1/2 second, or so.

Another factor is that the ATU only measure frequency to, I think, 8 
kHz. The net result may be that sometimes it's not in the frequency 
segment you think it should be in. Unless you have a very narrow band 
antenna, it shouldn't make much difference.

73,
Scott K9MA



On 12/10/2019 17:03, charles at k5ua.com wrote:
> After saving my KPA-1500 ATU impedance matching parameters on 80M at 
> 20 Kc intervals (3.510, 3.530, 3.550, 3.570, etc, etc), I expected 
> that the KPA-1500 ATU would automatically switch to the next set of 
> L/C values at the midpoint of the 20 Kc segments (like 3.520, 3.540, 
> 3.560, etc, etc), but I find that it switches randomly, sometimes just 
> 2 Kc away from the main tuning frequencies.  Does anyone have 
> information on how the ATU is supposed to work when it is polling the 
> xcvr for frequency?
>
> Thanks, K5UA
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-- 
Scott  K9MA

k9ma at sdellington.us