One of the reason you make an INV-L a bit longer is to address the capacitance you need to tune out the inductive reactance. Capacitance and capacitive reactance is an inverse relationship. See attached graph.
73 Mark K3MSB On Sun, Nov 18, 2018 at 10:59 AM F Z_Bruce <[email protected]> wrote: > > > > > -------- Original Message -------- > Subject: Re: Topband: Impedance of inv l? > Date: Sun, 18 Nov 2018 10:55:47 -0500 > From: F Z_Bruce <[email protected]> > To: [email protected], Topband <[email protected]> > > > > That sounds about right. As you put a good ground system under it, that > value will come down, and the efficiency will come up. > > Many add extra antenna wire that pushes the current up the wire, this also > raises the impedance, hopefully to near 50 ohms with the right length. > A capacitor (variable, then fixed) in series at the feed point can cancel > the added inductive reactance. > 73 > Bruce-k1fz > https://www.qsl.net/k1fz/beverage_antenna.html > > > On Sun, 18 Nov 2018 10:41:36 -0500, WW3S wrote: > > What should the Z be for a 1/4 wave inv l, with the radials attached to a > radial plate? Mine seems to be 60 ohms or so.... > > Sent from my iPad > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
