[Elecraft] Dusting off the old K3 & Considering a KAT3A

[Bill Frantz]

Sorry Jim. You are indeed correct about the feedline SWR. While 
there are other SWRs within the radio, they aren't of much interest.

However, these radios do report a SWR in the UI, and that is 
what I was referring to. Since a naive user might look at that 
figure and say, "The SWR is 2. The antenna must be good.", it is 
important to know that the tuners can produce a low figure on 
that meter with nothing connected to the antenna connector.

73 Bill AE6JV

On 8/30/17 at 11:25 PM, jim at audiosystemsgroup.com (Jim Brown) wrote:

>Please don't perpetuate that myth, Bill.  Tuners do NOT reduce 
>the SWR unless they're at the antenna end of a transmission 
>line. The SWR exists on the transmission line, and it is 
>determined ENTIRELY by the match between the transmission line 
>and the load.
>
>What tuners at the rig do is get the rig to put power into the 
>tuner (and hopefully, onto the transmission line).  If the SWR 
>is high without the tuner, it is equally high WITH the tuner. 
>Depending on the cable, the frequency, and the SWR, much of the 
>power that the rig puts into the tuner gets to the transmission 
>line, but is turned into heat by the SWR in the line and 
>doesn't get to the antenna.
>
>A better way to talk and think about this is to say that the 
>tuner can match a wide variety of loads to the transmitter 
>sufficiently well that the rig can pump the maximum power from 
>its output terminals, whether it's feeding a short wet string 
>or a nice long wire we've launched into a tree. And if there's 
>no transmission line, SWR has no meaning!  So SWR is the wrong 
>way to talk and think about it.
>
>73, Jim K9YC
>
>On 8/30/2017 10:15 PM, Bill Frantz wrote:
>>My experience with the tuners in both the K3 and KX3 are that 
>>they will reach an acceptable SWR with anything. I always 
>>check the antenna when they take a long time to reach a match. 
>>(I.e. lots of clicking.) Most of the time I find I am trying 
>>to match an open antenna connection.
>
>
>______________________________________________________________
>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
>Message delivered to frantz at pwpconsult.com
>
-----------------------------------------------------------------------
Bill Frantz        | Since the IBM Selectric, keyboards have gotten
408-356-8506       | steadily worse. Now we have touchscreen keyboards.
www.pwpconsult.com | Can we make something even worse?