[Elecraft] K3 KAT3 Antenna Tuner Tutorial

[Wayne Burdick]

Hi Don,

The manual is a bit sparse in this area -- I'll improve it next time.

> The user manual says that there are up to 30 ATU settings stored for  
> each antenna on each band by the antenna tuner.

Yes. 10 kHz per segment on 160 m, 20 kHz per segment on 80-12 m, 100  
kHz on 10 m, and 200 kHz on 6 m.

> There is no further discussion as to when a setting is saved or how  
> a setting is chosen from those saved.

When you hit ATU TUNE, the ATU checks the SWR and goes through the  
matching process if necessary. If so, new LC settings is saved for the  
present band segment.

> Is the frequency tracked as the VFO changes and a new setting put  
> into the antenna tuner when the VFO has been changed enough? Does a  
> setting get changed if the VFO has changed
> enough and the K3 instructed to transmit?

LC network changes do not occur in receive mode, as we found that very  
distracting. Instead they occur on band change or antenna change, or  
(if necessary) when you transmit.

If you have moved the VFO from one segment to another since the last  
transmission, and the best available LC settings have also changed,  
the ATU will automatically load the new settings when you transmit.  
The "ATU" icon flashes briefly to let you know this has occurred.

"Best available" is determined by comparing the present VFO location  
to segments for which LC data has been stored. Let's say you've tuned  
up the ATU only at 7000 and 7250 kHz on 40 m. If you move the VFO to  
7180 and transmit, the ATU will load the settings from the 7250 kHz  
bin, since that's the closest one.

>
> My antenna tuner seems to me to retune too often. Again my  
> expectations may
> not match how the tuner works.

This depends on the Q of the antenna. If Q is high (i.e. the antenna  
is narrow-banded), the ATU will retune more often. You could if you  
wish go through each band and tune up at the intervals mentioned  
above. On 160 m you'd start somewhere between 1800 and 1810 kHz, etc.  
But this is definitely not necessary.

Up to 30 LC settings are stored for both antennas on all bands.

All settings are saved in EEPROM so you don't have to retune if you  
power the radio off.

73,
Wayne
N6KR

>
> Some topics for said tutorial would include: (1) frequency spacing for
> tuning settings on each band, (2) does the tuner remember settings  
> for an
> antenna from one time when the radio was on to the next time the  
> radio was
> on, (3) does the tuner remember previous tuned setting from a  
> previous visit
> to a band, (4) how far the SWR must be off for the tuner to retune,  
> (5) how
> does the tuner indicate a failure to tune, (6) does it make sense to  
> tune
> ahead so to speak where you may want to have the antenna tuned up  
> ahead of
> an event?
>
> Don, N0YE
> -- 
> View this message in context: http://n2.nabble.com/K3-KAT3-Antenna-Tuner-Tutorial-tp3868991p3868991.html
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