[Elecraft] KPA-1500 ATU not working well

[John Oppenheimer]

Here is a picture and some plot images:

http://www.kn5l.net/Elecraft/CP1/

Not super accurate 60 and 100 Ohm loads, but provides an insight of the
coupler operation.

John KN5L

On 06/22/2018 04:15 PM, Wes Stewart wrote:
> I don't quite understand your methodology but there is one, apparently little 
> known caveat with the use of the "Elecraft" coupler topology.    AFAIK, this was 
> first used by John Grebenkemper, KI6WX, in his Tandem Match, described in QST, 
> January 1987.
> 
> Paul Kiciak, N2PK, mentions in his paper, "An HF In-Line Return Loss And Power 
> Meter", that this coupler suffers from poor input match at lower frequencies.  
> So the SWR meter has high SWR!
> 
> If the CP1 wasn't so expensive, I'd buy one just to measure it.