[Elecraft] KX3 atu anomalies - or it is me.

[Don Wilhelm]

Lucia,

The Elecraft tuner (I don't care if it is a KAT2, KAT1, KXT1 o KXAT3)  
cannot change the the SWR of the antenna itself.  The ATU will tune the 
antenna to an acceptable SWR so the PA  transistor in the transceiver 
are happy.  If you measure the SWR between the Tuner and the antenna, 
you will not see any change.  The internal tuner does change the 
impedance that is seen by the PA transistors, and that is the goal of 
antenna tuners.

73,
Don W3FPR

On 9/18/2012 10:36 PM, luca de marinis wrote:
> Hi Don, I read the 1.4 SWR on my MFJ 259b then tuned with the KX3 atu to 1.0
>
> On transmitting the swr graph showed peaks near to 2 and if I press the XMIT (tune) the reading is about 1.4 same as without ATU.
>
> Luca
>
>
>
>
> On Sep 18, 2012, at 7:12 PM, Don Wilhelm <w3fpr at embarqmail.com> wrote:
>
>> Lucia,
>>
>> You say that you had an SWR of 1.4, then used the ATU which lowered the
>> SWR to 1.0
>> OK, That was on the KX3 display.
>>
>> Please tell us where you were reading the continued 1.4 SWR.  The KX3
>> display does not show the SWR during transmit - only during a TUNE.
>> The SWR shown externally to the KX2 ATU will not change, so if you are
>> using an external device, you will not see any  change in the SWR reading.
>>
>> The KX3 ATU will reduce the SWR between the KX3 output PA and the input
>> to the KXATU3 to the value shown during on the KX3 display during a
>> TUNE, but the SWR between the KXATU3 and the antenna (as measured by an
>> external device) will not change.
>>
>> 73,
>> Don W3FPR
>>
>> On 9/18/2012 8:14 PM, luca de marinis wrote:
>>> Hi,
>>>
>>> I completed my KX3 #1715 few days ago and today I went to the park and using a Buddipole I tried to make some contacts. Buddipole swr was 1.4 on 20m so I used the ATU. It worked fine lowered the swr to 1.0 but then I transmitted I still could read a 1.4 swr. I moved up and down the band and tuned again and every time the ATU started from 9.9 and did the all cycle. Sometime couldn't go lower than 1.4. Sometimes after tuning the power was reduced to 2W
>>>
>>> Am I missing something. I did a search on the reflector but didn't show anything.
>>>
>>> Thank you in advance for your help
>>>
>>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>