Anyway
the difference in loss between #18 wire and RG-400 due to IR drop in the
length of wire in a balun is too small to worry about.

John Passaneau, W3JXP
Penn State University

=========================

Just like I said !

But a 1:1 choke balun has an indeterminate transformation ratio.

A 1:1 choke balun made out of coax "chokes" off current flowing on the
outside of shield, it has no effect on what is happing inside the coax
between the inside of the shield and the center conductor. If you made a
choke balun wound on a toroid or with beads with 2 foot of 75 ohm coax and
used it on an antenna with a Z of 50 ohms at 28Mhz. That 2 foot of 75 ohm
coax would transform the 50 ohms to 59.4+j21.3 ohms at the output end of
your balun. If this is a problem it's up to the user to decide but I
wouldn't like it. The same effect would happen if the balun was made with a
parallel conductor line be it "zip cord" or enameled wire. If the Z of the
line in the choke balun doesn't match the Z of the feed line it will cause
an impedance transformation that will with vary with frequency. Of course if
one is only using the balun at 7Mhz or lower it will not be as noticeable as
it is at 28MHz.

--
John Passaneau, W3JXP
Penn State University


"Reg Edwards" wrote in message
...

Anyway
the difference in loss between #18 wire and RG-400 due to IR drop in the
length of wire in a balun is too small to worry about.

John Passaneau, W3JXP
Penn State University

=========================

Just like I said !

But a 1:1 choke balun has an indeterminate transformation ratio.

When connecting a 50-ohm circuit to a 600-ohm line via a choke balun it
makes no difference what the impedance of the short length of line forming
the choke might be.

For practical purposes the severe mismatch is due entirely to the difference
between 50 and 600 ohms.

One must avoid suffering from delusions of accuracy.
---
Reg

That's true but sometime we use current baluns in 50 ohm systems and one
should be aware of what happens to the Z when the line in the balun is some
random impedance.
I've done some tests on various types of baluns looking at balanced to
unbalanced conversion verses frequency and losses and I like 3 to 4"
diameter toroids with a mu of 100 to 200 wound with Teflon coax. Most of my
antennas are close to 50 ohm and I don't need any unwanted impedance
transformations.


--
John Passaneau W3JXP
State College Pa

This mail is a natural product. The slight variations in spelling and
grammar enhance its individual character and beauty and in no way are to
be considered flaws or defects.


"Reg Edwards" wrote in message
...
When connecting a 50-ohm circuit to a 600-ohm line via a choke balun it
makes no difference what the impedance of the short length of line
forming
the choke might be.

For practical purposes the severe mismatch is due entirely to the
difference
between 50 and 600 ohms.

One must avoid suffering from delusions of accuracy.
---
Reg