On Sun, 02 Jan 2005 14:19:17 GMT, "pegge"
wrote:
I´m planning to build a new multi-band antenna, and found something
entirely new to me , an antenna like a w3dzz but with ´stubs´instead of
traps.
http://www.g3ycc.karoo.net/lattin.htm

Hi Pegge,

This is one of those designs that has elements of authenticity, but
poor implementation. In other words, it does not work in the way it
is described (and is notorious for not working at all).

The elements of authenticity are with stubs as you have noted. Open
and closed stubs do replace lumped circuits of inductors and
capacitors to function as traps and loads. The poor implementation is
that you do not construct stubs to replace those traps or loads in the
ways commonly described (and the added stringer wires only compound
the poor logic).

Every implementation I've observed consists of building the stub
without feeding it across its mouth, but along its body. This makes
the other half of the stub (the total structure now no longer a stub)
simply a parasitic wire with no particular merit.

Proper stubs on VHF/UHF antennas that can support them, give the
proper orientation of being at 90° to the radiating structure (unlike
the Lattin). Sometimes the stub is compressed by folding or rolling
its length around the antenna, but the mouth is always in series with
the radiating element. In other words (use fixed font to view one
half of a dipole, source on the left as § ):
§------------------ -------------------
| |
| |
| |
--
But not:
§-----------------------------------------
|
---------

To build the Lattin style with mouth fed stubs (and probably not
functioning as traps), would require three wire constructions:
§---------------------------
|
---------
|
-----------------------
Which is now verging on the concept of a Franklin Antenna which you
should research in place of Lattin styles. However, I would point out
that the Franklin is a single band gain antenna. I only mention it to
study as it gives a better theoretical description (and works because
of it).

73's
Richard Clark, KB7QHC