In article .com,
"RHF" wrote:

ARNE,
.
"Ununs" = 'UN' to 'UN'
{ Unbalanced-to-Unbalanced Matching Transformer }
http://groups.yahoo.com/group/Shortw...a/message/4900
.
UN #1 = Unbalanced Longwire (Random Wire) Antenna and Ground.
.
UN #2 = Unbalanced Coax Cable Feed-in-Line
.
Links/URLS To Read :
http://tinyurl.com/exk6u
http://tinyurl.com/by4g6
http://www.bytemark.com/products/bkgndbal.htm
http://www.bytemark.com/products/tlttheory.htm
http://standards.ieee.org/reading/ieee/ept/trans.pdf
.
.
Understanding, Building and Using Baluns and Ununs
[ Theory and Practical Designs for the Experimenter ]
- by Jerry Sevick [W2FMI]
http://www.universal-radio.com/catalog/books/0558.html
.
Dr. Sevick is the authority on transmission line transformer theory.
This book provides a unique opportunity to learn about
the application of baluns and ununs for dipoles, yagis,
log periodics, beverages, antenna tuners and countless
other examples. - New Edition © 2003 CQ Publishing - Pages 136

Snip

This is a different approach to impedance matching one, which I became
aware of only a couple of years ago. These types of UNUNS and BALUNS are
non DC isolating choke types instead of the more familiar voltage type
of transformer. The main advantages are very broad band response and
high efficiency. Generally this approach is the one to use except for
very long wire antennas like a beverage where you would want that
isolation. You may not want to consider this type of transformer on a
voltage sensitive antenna of any type because it will not offer any kind
of static protection. This type would be the safest to use with a loop
type antenna as an example where the antenna is DC grounded.

--
Telamon
Ventura, California