Hi there,
Wasn't there a way with "bazooka" antenna to get a wider bandwidth of any
antenna? I will remember that you could use a parallel resonator to extend the
bandwidth on any antenna. An other way was to have a "return" parallel with
the radiator such as you see in a the folded dipole. They have wider bandwidth
than the "simple" dipole. I have seen a wideband navy GP antenna that had a
wire from the top to ground of the radiator that widened the bandwidth. That
should be a possible method for your 80 M vertical. The "wire extender" should
be thinner than the radiator.
What I remember (from my old and lousy) memory if you have different
diameter on the dipole and the "fold-over" a large diameter dipole with a thin
fo
ld-over the feeding impedance is closer to 75 ohms. If the diameters are equal
you have a feeding impedance closer to 300 ohms. Consequently, if the fold-over
part has a larger diameter than the "dipole" part the feed impedance will be
even higher that 300 ohms. (This was used as a trick to keep a 300 ohm
feeding impedance in TV yagi in the "old" days)
73 de N2JFS
Hans
____________________________________
From: w8zn@comcast.net
To: towertalk@contesting.com
Sent: 3/16/2009 3:18:28 P.M. Eastern Standard Time
Subj: [TowerTalk] Bandwidth of a 1/4wl 80m vertical
Hi all,
To those running 80m 4 squares, what kind of bandwidth do you typically see?
Is it about the same as a typical dipole or 1/4wl sloper? Does anyone know
if using a larger radiator (such as Rohn 25 vs 3"/4" irragation pipe) gives
broader bandwidth or is the diameter to wl ratio just too small to make any
diff?
thanks!!
Terry
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