A BALUN is not a transformer. If impedance matching is required, from the
feedpoint toward the coax feed:
1) Attached at the feedpoint of the wire: The transformer to match
impedances, then
2) In series between the transformed impedance side of the transformer and
the BALUN.
The sole purpose of a BALUN is to bilaterally modify the circuit (not a
part of the antenna) from differential mode to common mode (the coax cable).
Note that even with a good counterpoise (other than the coax outer surface
of the shield) the EFW is NOT a balanced source/load. It's unbalance
varies as a function of frequency.
Enough
Dave - W?LEV
On Mon, Feb 26, 2024 at 10:22?PM Ray W8LYJ via groups.io <rcbenedict1545=
[email protected]> wrote:
If an antenna is fed at the end it¡¯s an end fed regardless of length.
There are 1/4 wave end fed AM broadcast and 1/2 wave end fed AM broadcast
antennas.
The BALUN is not part of the antenna it¡¯s just a fixed antenna tuner with
maybe a common mode choke
If the wire is a half wave then the feed point impedance will be high,
2000 ohms or more. The BALUN turns ratio depends on the antenna feed
point impedance.
Ideally the feed point impedance would be measured and the appropriate
BALUN constructed.
--
*Dave - W?LEV*
--
Dave - W?LEV
