[Elecraft] Not sure my KX1 ATU is working correctly

Don Wilhelm w3fpr at embarqmail.com
Mon Jan 2 13:30:37 EST 2012


James,

I am not sure from your prblem description whether you have a KX1 
receiver problem or a KXAT1 problem or some sort of setup problem with 
your shack tuner.

First thing to do is to peak the KX1 receiver front end, and you remove 
the tuner (put the jumper in) and connect it to a signal generator or to 
an antenna that presents close to a 50 ohm load.

Do the following things in order:
You have a shack tuner, so I suggest you set it for a 1:1 SWR - you can 
do that with another transmitter or with an antenna analyzer - set it up 
first for 20 meters.

Once you have a 50 ohm signal source connected to the KX1 input, peak 
the 20A and 20B trimmers for the maximum output from the KX1.   Re-tune 
your shack tuner to 40 meters, then connect the KX1 and peak the 40 
meter trimmer - it must be done in that band order, reversing it will 
only lead to frustration.

After having done that, you can remove the jumper and install the KXAT1 
and set ATU to CAL
First connect a good 50 ohm dummy load and balance (null) the wattmeter 
with the trimmer capacitor.  If you can obtain a good low millivolts 
reading, that is good - above .010 volts is bad, below .003 volts may be 
the best you can do.

With the KXAT1 still in CAL, again tune your shack tuner to 50 ohms on 
20 - now you can compare the KX1 receive with you other receiver.  Then 
set the ATU menu to "tun" and it should tune to less than 1.2 and you 
should still be able to hear signals at the same level as before

Switch your shack tuner to 40 meters and do the same as you did on 20.

After doing that, if you still have a problem, ask again.

On 1/2/2012 12:34 PM, james1787 at aol.com wrote:
> Hi Folks,
> I just finished putting together my KX1 with the ATU. I am having a problem with it on 20m when using it through my shack tuner (viking matchbox to a dipole up 60-70 ft). As the manual states, I place the tuner into CAL to bypass the tuner. The problem is that it seems kind of quiet. I listen to a loud S-9 signal on my IC-746pro and it is much quieter on the KX1. For kick's I placed it in the tuner-on setting and hit tune. It tuned for a seconds and now it's louder. I tapped the key and it went back to being quiet.
> ?
> I didn't seem to notice this on 40m last night and made a few QSO's.
> ?
> Just wondering where I might check to see that everything is ok. I wonder if C9 on the ATU is set correctly? With my DMM I was able to get the voltage down to almost zero.
> ?
> Thanks&  73,
>


More information about the Elecraft mailing list