The BOBTAIL is a 3 element upside down vertical.
It looks like a block letter E turned over on it's side
with the connecting wire on top.
It can also be implemented as a 2 element,
fed directly at the upper corner with 50 ohm coax,
pulling the coax away from the wires.
Tom N4KG
On Wed, 14 Nov 2001 Chris BONDE <ve7hcb@rac.ca> writes:
>
> Has anyoe tried an upside down vertical?
> Rmember reading about one for 40m awhile back. If corrct in my
> recall, it
> had the readial on the top and the vertical feed up there hanging
> down. From a tree.
>
> Chris opr VE7HCB
>
>
> At 12:41 PM 2001-11-13 -0600, n4kg@juno.com wrote:
>
> >The simplest (Low) antenna that will be useful for
> >working DX is a VERTICAL with a GOOD radial field,
> >which means 30 or more radials as long as you can make
> >them, up to 1/4 Wavelength.
> >
> >A wire can be dropped from a tree limb for the vertical element
> >or you could stack 3 pieces of 1-1/4 inch diameter fencing,
> >with insulated guys.
> >
> >See the ARRL Antenna Book or Handbook for illustrations.
> >
> >Another good antenna is a vertically polarized Delta Loop,
> >fed 1/4 WL down from the apex. (Corner feed will work but
> >has a tilted orientation). Total Length = 1005 / F (MHz).
> >If the bottom wire is close to the ground, you will need to
> >shorten this by about 3%. Feed impedance is around 100
> >ohms which can be matched using a 1/4 WL (electrical)
> >75 ohm line (RG59) which comes to 46.6 ft on 40M or
> >(23.3 ft on 20M) if you use solid dielectric coax
> >(velocity factor 0.66).
> >
> >With the high level of solar activity, 20M should also
> >be open most, if not all, of the night.
> >
> >The MFJ 1793 vertical covers 80, 40, and 20 Meters,
> >standing around 35 ft tall. It requires radials and
> >insulated guys. Price is around $160. It is a good
> >design, both electrically and mechanically.
> >
> >Tom N4KG
> >
> >
> >
> >
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________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today! For your FREE software, visit:
http://dl.www.juno.com/get/web/.
List Sponsored by AN Wireless: AN Wireless handles Rohn tower systems,
Trylon Titan towers, coax, hardline and more. Also check out our self
supporting towers up to 100 feet for under $1500!! http://www.anwireless.com
-----
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
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