On the drawing it does not show any 125 ohm cable, but I think what you are saying is that from the feedpoint of the folded dipole, inside the tubing there is a 1/4 wavelength piece of 125 ohm cable (about 13.5 inches at 2m) that is joined to 50 ohm cable. What we see exiting the tube (opposite the feedpoint) is the 50 ohm stuff. If this is correct it fully explains a drawing on the previous page showing a cross section of a single element folder dipole. \
lh On 5/18/10, N1BUG <p...@n1bug.com> wrote: > > > > Thanks. That makes sense and should work out quite well for a > harness external to the mast. Of course the quarter wave of 125 ohm > coax will still be required inside each dipole, but the use of all > 50 ohm coax beyond that point simplifies construction. > > Apparently Sinclair had different ways of doing it, perhaps > depending on the exact model. Or maybe they changed the harness > design at some point. > > Paul N1BUG > > Larry Horlick wrote: > > > > > > I have a drawing from Sinclair that shows 4 stacked folded dipoles (it > > does not indicate an > > antenna model) using all 50 ohm cable. So using the 210C4 harness > > picture from the link > > below as a template, this is how it's done: > > > > Feedlines from dipole A, B, C, and D are any length, but identical. A > > and B go to a tee, > > C and D go to another tee. The feedlines from the output (if I am > > allowed to use that rather > > crude term!) of these tees are any odd 1/4 wavelength (but do not have > > to be the same) and go > > to a 3rd tee. The output of this tee is 50 ohms. I suspect that the > > harness does not affect the > > pattern, but rather it is the dipole to mast spacing. > > > > lh > >
