Let me answer each question below

"Buck" wrote in message
...
On Thu, 9 Jun 2005 16:30:18 -0400, "Fred W4JLE"
wrote:

Given an antenna that has 50 Ohms +J0, feed it with 50 ohm line and the
swr
for the system is 1:1, substitute a 1/2 wave of 450 ohm line and the
antenna
and the rig are both at 50 ohms. The SWR on the feedline is 450/50 or
9:1.

Exactly correct, actually you can replace it with 1/2 electrical wave length
of anything including lampcord. That being said you should not use lamp cord
before someone has a cow.



Ok, just to reiterate so I know I understand (and you can see if I
don't), If I feed a 20 meter dipole cut for my favorite frequency, I
can feed the radio with exactly 1/2 wave of 450 ohm feedline and it
will match the radio? Of course, coax will make a better match (with
less loss?)

No coax won't make a better match, a match is a match. The loss is lower on
the ladder line. The use of ladder line for a dipole designed for and used
on a single band probably doesent make a lot of sense. If you want to run an
80 meter dipole on all bands it is a must (sans a tuner). Look at it this
way 450 Ohms divided by 50 Ohms = 9 an 18:1 SWR at 450 ohms is only 2:1 at
50 ohms.

Now, if I understand, the principle of the 130 foot dipole matching
the rig is based on the length of 450 ohm twin-lead. The twin lead is
always 1/2 WL long.

NO SEE MY OTHER REPLY

The coax and rig are 50 ohms, but according to
the smith chart, the impedance of the various frequencies range from
20 to 100 ohms. This would make me wonder why I don't get the same
impedances at my rig, or at least at my feed point of 50 ohm coax.


Thanks


--
73 for now
Buck
N4PGW