Impedance transformation question
 

Hi,

If EZNEC reports a source impedance for a balanced antenna, such as
a loop, of R+-jX ohms, and I am trying to match the antenna to the
line: I am using a Smith Chart program that is unbalanced i.e.
everything is respect to ground. Question is, what impedance do I
enter into the program such that I will get the correct matching
solution for the balanced antenna? I have used this program numerous
times and it works well for verticals, mobiles, and other unbalanced
antennas. Thanks.

Gary N4AST

Impedance transformation question
 

wrote in message
oups.com...
Hi,

If EZNEC reports a source impedance for a balanced antenna, such as
a loop, of R+-jX ohms, and I am trying to match the antenna to the
line: I am using a Smith Chart program that is unbalanced i.e.
everything is respect to ground. Question is, what impedance do I
enter into the program such that I will get the correct matching
solution for the balanced antenna? I have used this program numerous
times and it works well for verticals, mobiles, and other unbalanced
antennas. Thanks.

Gary N4AST


Hi Gary

Is it practical for you to use a Smith Chart rather than a "Smith Chart
program"? A Smith Chart doesnt concern itself with ground. It is mearly
a plot of all possible R+/-jX with real R.

Jerry

Impedance transformation question
 

Impedance transformation question
 

On Apr 27, 3:24 pm, wrote:
Hi,

If EZNEC reports a source impedance for a balanced antenna, such as
a loop, of R+-jX ohms, and I am trying to match the antenna to the
line: I am using a Smith Chart program that is unbalanced i.e.
everything is respect to ground. Question is, what impedance do I
enter into the program such that I will get the correct matching
solution for the balanced antenna? I have used this program numerous
times and it works well for verticals, mobiles, and other unbalanced
antennas. Thanks.

Gary N4AST


The impedances will still be the same. If you want to keep things
balanced, though, split any series elements into two equal parts. For
example, if your program says to use 20pF in series, use 2 40pF caps,
one on each side, to keep things balanced. With an inductance, use
two inductors that are half as large as the single one. The idea is
the two caps in series or the two inductors in series make the
specified net capacitance or inductance. With shunt elements, there's
no need to do that, just don't ground either side---the shunt elements
go across the balanced network from one side to the other.

Cheers,
Tom

Impedance transformation question
 

On Apr 27, 5:54�pm, K7ITM wrote:
On Apr 27, 3:24 pm, wrote:

Hi,

* If EZNEC reports a source impedance for a balanced antenna, such as
a loop, of R+-jX ohms, and I am trying to match the antenna to the
line: *I am using a Smith Chart program that is unbalanced i.e.
everything is respect to ground. *Question is, what impedance do I
enter into the program such that I will get the correct matching
solution for the balanced antenna? *I have used this program numerous
times and it works well for verticals, mobiles, and other unbalanced
antennas. *Thanks.

Gary N4AST

The impedances will still be the same. *If you want to keep things
balanced, though, split any series elements into two equal parts. *For
example, if your program says to use 20pF in series, use 2 40pF caps,
one on each side, to keep things balanced. *With an inductance, use
two inductors that are half as large as the single one. *The idea is
the two caps in series or the two inductors in series make the
specified net capacitance or inductance. *With shunt elements, there's
no need to do that, just don't ground either side---the shunt elements
go across the balanced network from one side to the other.

Cheers,
Tom

Hi Tom, Thanks, I just wanted to confirm what appeared to be
happening.

Gary N4AST