Jim, you are right, it is not a balun, it is a common mode choke, you can see it this picture from an Vertical I had ( http://paginas.fe.up.pt/~ee04056/CT1ILT/pics/tvertical/version1/thumbs/15.JPG )
maybe we can try a QSO tonight? Filipe CT1ILT Citando Jim Brown <[email protected]>: > On 1/26/2012 1:48 PM, [email protected] wrote: >> I measured the impedance at the base and it is Z = 23 + 9j with VSWR >> of 2 to 1. > > If that is a good measurement, i wouldn't bother with a matching network. > >> The VSWR after 50m of coaxial cable and a home made 1:1 balun (made >> with coax) is 1.7 to 1. > > What do you mean by "balun?" Did you wind turns of the coax around a > ferrite core? That is NOT a balun, it is a common mode choke. Some > people who don't know better call it a "current balun." A common mode > choke like this does NOT affect the VSWR or the loss in the coax (except > for the small additional length of coax it takes to wind the choke). > > Based on your VSWR measurement and your impedance measurement, I'd say > you're in pretty good shape, at least from the perspective of matching > to the TX. Good luck in the contest. > > 73, Jim K9YC (California, Near SF) > > _______________________________________________ > UR RST IS ... ... ..9 QSB QSB - hw? BK > _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
