Paul, The circulating current in the secondary winding of the transformers limit the power handling capability. If you want to know more about this type of directional coupler, refer to John Grebenkemper's (KI6WX) Tandem Match article which has been featured in many issues of the ARRL Handbook as well as the Antenna Book.
73, Don W3FPR > -----Original Message----- > > Now another: What is the limiting factor in the power rating of > the coupler? > With either the 20db (max 25W), or the 30db (max 250W) the power delivered > to the secondary is 0.25W. The terminating resistors are rated at 3W. Are > there high circulating currents in the core that limit the power level, or > is there some other mechanism that I am overlooking? Is the power > rating of > a torroid something that can be calculated in the design, or must it be > derived empirically? > > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
