On Dec 29, 8:05*am, RHF wrote:
On Dec 29, 5:42*am, Dave wrote:
Telamon wrote:
In article ,
*Dave wrote:
John Smith wrote:
However, in side-by-side comparisons on 10-6-2m antennas I have built,
comparing a 5/8 against the 1/2 (construction methods/materials and
matching components identical) ... the actual difference, in the real
world, must be less than the width of a meter needle in the readings ...
or, put simply, I no longer deal with the extra length required of the
5/8 ... your mileage may vary ...
The advantage of a physical height (antenna length) *between 180 and 215
degrees (see previous post regarding the magic number being around 195
degrees) is improved take-off angle and reduced skywave-groundwave
interaction, not dramatic nearfield voltage increases.
Regarding Mr. Smith's comments above my experience and others is the
opposite. 5/8 is a much better performing antenna than a 1/2 wave for
local VHF and UHF communications. Well worth the effort to build a 5/8
wave antenna over a 1/2 wave. The 5/8 had some kind of series load coil
part way up the whip where the 1/2 wave match/compensation was done at
the base so the whip was solid. Sorry I can't more specific then that as
those experiments were many years ago.
Mr. Smith is still lost in space.
- 5/8 wavelength antennas do not require a ground plane, do they?
Dave here is a Picture of a . . .
5/8 WL Ground Plane Antennahttp://home.att.net/~wizardoz/cbmw/Images/antenna2.gifhttp://users.belgacom.net/hamradio/schemas/50mc58golf.gifhttp://users.belgacom.net/hamradio/schemas/on6muvhf58verticalantenna.htm
*.
CBers use 5/8 WL Ground Plane Antennas very often.http://cgi.ebay.com/_W0QQitemZ260334577278
* Elevated Vertical Element
* Load Matching Device
* Ground Plane Radialshttp://www.pacificaerials.co.nz/antInfo/antennaTypes.htm#3
*.
FWIW the 5/8 WL* does go 'mobile' as a Vertical "CB"
Antenna but it uses the Car's body as the Ground Plane.http://www.firestik.com/Catalog/FS2-FS5.htm
* They do require Tuning {Matching} for Transmithttp://www.firestik.com/Tech_Docs/TUNABLE.htmhttp://www.firestik.com/Catalog/FS2-FS5.htm
*.
Some where I remember a 5/8 WL Vertical Element
on top of a 5/8 WL Vertical Mast {Grounded} as being
a very good Antenna : Mono-Pole ? Collinear ?
http://www.signalengineering.com/ultimate/verts.jpg
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:Ground Level
~ RHF