Co-ax

[Glen Zook]

The largest difference is that RG58/U is 50 ohms and
RG59/U is 72 ohms impedance.  RG59/U will also take
slightly more power primarily due to its slightly
larger size.

RG59/U was used for years as TV feedline with a 4:1
balun from the "normal" 300 ohm impedance of the
"normal" TV antenna.

For amateur use, RG59/U actually matches things like
dipoles above 1/2 wavelength above ground better than
50 ohm coax (the impedance of such an antenna centers
around 75 ohms) and it is used as 1/4 wave (or odd
multiple lengths of 1/4 wave) matching lines when
stacking beams (very handy at VHF).  Basically a 50
ohm antenna feed impedance is transformed to 100 ohms.
 When two 100 ohm feeds are fed in parallel (like
connecting to a "T" connector), this again puts the
impedance at 50 ohms.

Even most of the newer amateur equipement with the
"fixed" 50 ohm output will work fine with the 72 ohm
coax.  Of course the old boat anchor stuff that can
match a "wet noodle" doesn't even think about the
difference between 50 and 72 ohms.

Glen, K9STH


--- Martin Tippin <w0akg at AEROSURF.NET> wrote:

Can some one tell me the diff. between 58U and 59U?


=====
Glen, K9STH

Web sites

http://home.attbi.com/~k9sth
http://home.attbi.com/~zcomco

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