Actually 300 ohms is special. It is the impedance of a folded dipole with equal diameter elements, the end result of bending a single piece of tubing into a U. And the impedance is not affected by the spacing between the elements (according to the handbook theory).
Burt VE2BMQ John Sehring wrote: > > > Yes, it does depend on the antenna, to wit, diameter of the elements & > spacing between the elements. Can be made lower or higher than 300 > ohms. There's nothing "sacred" about 300 ohm Z. It was a match for 300 > ohm TV twinlead in the older daze. > > --John > > --- On *Thu, 8/27/09, Chuck Kelsey /<[email protected]>/* wrote: > > > From: Chuck Kelsey <[email protected]> > Subject: Re: [Repeater-Builder] 2 meter folded dipoles for multi bay > design information needed > To: [email protected] > Date: Thursday, August 27, 2009, 6:51 AM > > > > Depends on the antenna. > > A folded dipole, out in the open, with no matching, is a > bit less than 300-ohms. > > > Chuck > WB2EDV > > > > start: 0000-00-00 end: 0000-00-00 > >
