[Elecraft] 1:16 unun

Thu Dec 18 14:05:01 2003

A SPICE simulation is good for investigating the effects of not having =
the correct T-line impedance. In this case you need 200 ohm line this =
can be built with parallel wires spaced with Kapton or similar tape. =
Twisted pair is about 100 ohms. If you tell me the length of wire in the =
16:1 balun I can run a sim of a current mode balun. Now this is a UNUN, =
is it not? If built from four T-lines, and using three cores, you will =
need j2400 ohms across the top core to reduce the unun current-to-ground =
to 1/4 of the antenna current. This will require 110 uH for 3.5 MHz.=20

   Dave=20

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Charles Greene
Sent: Thursday, December 18, 2003 4:43 AM
To: Michael Fitzgerald; [email protected]
Subject: Re: [Elecraft] Broadband Antenna

Hi,

  A 16:1 balun is easy. Just use 4 wires.  (ratio =3D N^2)  It's where =
you=20
try to get in between where it gets hard.