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Re: Not sure my KX1 ATU is working correctly

Posted by James1787 on Jan 02, 2012; 8:22pm
URL: http://elecraft.85.s1.nabble.com/Not-sure-my-KX1-ATU-is-working-correctly-tp7144358p7144745.html

Hi Don,
I followed your instructions and did the following:
I removed my ATU from the KX1 and put the jumper in place.
With my shack tuner, using my Icom I tuned it for a perfectly?flat SWR on 20 meters.
I moved the coax from my Icom to my KX1.
I peaked the 20a and 20b trimmers
I moved the coax back to my icom and tuned the shack tuner for 40 meters
I moved the coax back to my KX1 and peaked the 40 trimmer
I removed the jumper in the KX1 and re-installed the ATU and set it to CAL.
I connected the KX1 to my dummy load (Bird ERI-003F 150 watt 50 ohm dummy load)
I changed bands on the KX1 to 20m
I proceeded to adjust trimmer capacitor C9.
I was able to get the voltage to .000 (it had a range from about 2.9 volts and bottomed out at .000).
The power meter was only showing about 2.8 watts and the SWR showed 1.0
I connected my icom back up and re-tuned the antenna for 20m
I moved the coax from my icom back to my kx1.
With the KX1 still in cal, I pressed tune. Now the power was showing about 1.9 watts and 9.9 (infinite) SWR.
I moved the from the KX1 to my icom and tuned the antenna for 40m.
I changed bands on the KX1 to 40m
I moved the antenna from my icom back to the kx1 and made sure it was stil on CAL. I pressed tune and it was showing 2.9 watts out and 1.0 swr.
?
These are the results. I'm not sure if I was supposed to see it dip to .000 volts or not.
It definitely appears the issue is something with 20m. I wish I had a wattmeter for QRP to see what the power/swr was doing without the ATU on 20m.
Also, I have a 13.8 volt supply connected, 3 watts sounds a bit low?
?
73,
James KB2FCV
?




-----Original Message-----
From: Don Wilhelm <[hidden email]>
To: james1787 <[hidden email]>
Cc: elecraft <[hidden email]>
Sent: Mon, Jan 2, 2012 1:30 pm
Subject: Re: [Elecraft] Not sure my KX1 ATU is working correctly




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, [hidden email] 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,
 >
 

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