[Central-Electronics] 600L coupler replacement

[kihwal at yahoo.com]

I did not duplicate the original coupler design. I replaced them with PI-network. It is hard to lower the Q sufficiently on 10m to obtain a bandwidth of more than  about 700kc due to 813's internal and stray capacitance. Adding more stages will help, but there is no space for that.
It will be nice if the CE couplers can be modeled with a modern tool and analyzed/designed/duplicated with modern materials.
73Kihwal, K9SUL
 

    On Tuesday, January 24, 2017 10:14 PM, Jim Candela <jcandela at prodigy.net> wrote:
 

 Lee,
    What you have done is show that mortal men can understand and build a coupler! Very nice work OM.Now i need to collect your info, and study.
Thank YouJimWd5JKO
 

    On Tuesday, January 24, 2017 12:34 PM, Kihwal Lee via Central-Electronics <central-electronics at mailman.qth.net> wrote:
 

  blockquote, div.yahoo_quoted { margin-left: 0 !important; border-left:1px #715FFA solid !important; padding-left:1ex !important; background-color:white !important; }  My 600L had a  bad ouput coupler on 10m and 15m. Each one has been replaced with a pi matching network. In the process of designing the networks, the working ones were analyzed. They are designed to match 3900 ohms to 50 ohms and that's exactly what Joe Batchelor's coupler patent uses as an example. 
Details at http://k9sul.fayoly.net/projects/ce600l/ 
One thing that still doesn't work is the load mismatch relay, which I replaced with a modern 110VDC 10kohm coil relay. It gets engaged at first when the plate supply is turned on. But if the plate supply is turned off and turned back on, the relay doesn't engage. Pushing the reset button or sensitivity adjustment doesn't help. 
This is a beaten up unit with extra holes here and there, so I do not care too much about preserving the original circuit and the look. 
73,Kihwal, K9SUL

Sent from Yahoo Mail for iPhone
  
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