I am trying to build a balun. I chose the one on this web site as I like the
design
http://www.hamuniverse.com/balun.html
It states that, and I quote
"The number of turns is not critical because the inductance depends more on
the length of the wire (coax) than on the number of turns, which will vary
depending on the diameter of the plastic pipe that is used."
But it does not give the formula. It just says 18 to 21 feet.
I plan to use 4 inch pvc and I want to cover as much of the upper 11 meters
as I can. Am I better off at 18 or 21 feet?

On Mon, 9 Jan 2006 20:53:56 -0600, "DrDeath"
wrote:

I am trying to build a balun. I chose the one on this web site as I like the
design
http://www.hamuniverse.com/balun.html
It states that, and I quote
"The number of turns is not critical because the inductance depends more on
the length of the wire (coax) than on the number of turns, which will vary
depending on the diameter of the plastic pipe that is used."
But it does not give the formula. It just says 18 to 21 feet.
I plan to use 4 inch pvc and I want to cover as much of the upper 11 meters
as I can. Am I better off at 18 or 21 feet?


I built one like the one on the right. I used my Hustler 5BTV manual, and it
said to use a 10 turn 6 inch form. That was a bitch to find a 6 in form. SO I
found the website above, and used the left as a model. The 4" PVC does not quite
give you 6 inches in form. But as the website states, if you butt to couplers
together, that will give you a 6 inch form. The couplers are 5 inches at the
outside edges. By the time the cable is wrapped around it, it's about 6 inches.
I figured that was as close as I could get. As the website mentioned, I used the
4" PVC pipe as a joint to butt the couplers together, to make them hold better.
So, I don't know if I used 18-21 feet, but I think I am pretty damn close.

Vinnie S.

"Vinnie S." wrote in message
...
On Mon, 9 Jan 2006 20:53:56 -0600, "DrDeath"

wrote:

I am trying to build a balun. I chose the one on this web site as I like
the
design
http://www.hamuniverse.com/balun.html
It states that, and I quote
"The number of turns is not critical because the inductance depends more
on
the length of the wire (coax) than on the number of turns, which will vary
depending on the diameter of the plastic pipe that is used."
But it does not give the formula. It just says 18 to 21 feet.
I plan to use 4 inch pvc and I want to cover as much of the upper 11
meters
as I can. Am I better off at 18 or 21 feet?


I built one like the one on the right. I used my Hustler 5BTV manual, and
it
said to use a 10 turn 6 inch form. That was a bitch to find a 6 in form.
SO I
found the website above, and used the left as a model. The 4" PVC does not
quite
give you 6 inches in form. But as the website states, if you butt to
couplers
together, that will give you a 6 inch form. The couplers are 5 inches at
the
outside edges. By the time the cable is wrapped around it, it's about 6
inches.
I figured that was as close as I could get. As the website mentioned, I
used the
4" PVC pipe as a joint to butt the couplers together, to make them hold
better.
So, I don't know if I used 18-21 feet, but I think I am pretty damn close.

Vinnie S.

I can get 6" pvc. Start with 21 and work my way down till we get the desired
effect.

The amount of inductance is determined by the number of coils
and how closely spaced together they are. There is not going
to be much difference in three feet. Maybe wrapping the coil
with aluminum foil would help to increase the coupling on
the coil to increase the inductance.

Inductors are the exact electrical opposite of capacitors.

Capacitors block DC and pass AC. They have decreasing reactance
to higher frequencies. Current leads the voltage by 90 degrees.

Inductors block AC and pass DC. They have increasing reactance
to higher frequencies. Current lags the voltage by 90 degrees.

The inductance in the coil only affects the outside of the shield,
the exact place you don't want current flowing. It won't affect
the signals inside the coax.

"Scott in Baltimore" wrote in message
...
The amount of inductance is determined by the number of coils
and how closely spaced together they are. There is not going
to be much difference in three feet. Maybe wrapping the coil
with aluminum foil would help to increase the coupling on
the coil to increase the inductance.

Inductors are the exact electrical opposite of capacitors.

Capacitors block DC and pass AC. They have decreasing reactance
to higher frequencies. Current leads the voltage by 90 degrees.

Inductors block AC and pass DC. They have increasing reactance
to higher frequencies. Current lags the voltage by 90 degrees.

The inductance in the coil only affects the outside of the shield,
the exact place you don't want current flowing. It won't affect
the signals inside the coax.

This recipe states that the amount of coils is unimportant and to wrap them
as close as possible without over lapping. This balun relies on the length
which has a 3 foot margin.

On Tue, 10 Jan 2006 01:31:51 -0500, Scott in Baltimore
wrote:

+The amount of inductance is determined by the number of coils
+and how closely spaced together they are. There is not going
+to be much difference in three feet. Maybe wrapping the coil
+with aluminum foil would help to increase the coupling on
+the coil to increase the inductance.
+

If you want to increase the inductance wrapping aluminum foil on the
outside is not going to produce adequate results. Instead, place
ferrite material within the form so that it sits inside the windings.
If you want to decrease the inductance use aluminum inside the
windings.

This is how tunable inductors work.

+The inductance in the coil only affects the outside of the shield,
+the exact place you don't want current flowing. It won't affect
+the signals inside the coax.
****

Coiling coax up to form a choke balun places an impedance inline with
the outer conductor of the coax. It is this impedance that limits or
"blocks" unwanted current from flowing down the outer shield of the
coax. Coiled baluns should be located as close to the feed as
possible.

james

"james" wrote in message
...
Coiling coax up to form a choke balun places an impedance inline with
the outer conductor of the coax. It is this impedance that limits or
"blocks" unwanted current from flowing down the outer shield of the
coax. Coiled baluns should be located as close to the feed as
possible.

james

When you say as close to the feed as possible. Do you mean the radio or the
dipole? I'm assuming the dipole.

On Mon, 9 Jan 2006 22:40:51 -0600, "DrDeath"
wrote:

I built one like the one on the right. I used my Hustler 5BTV manual, and
it
said to use a 10 turn 6 inch form. That was a bitch to find a 6 in form.
SO I
found the website above, and used the left as a model. The 4" PVC does not
quite
give you 6 inches in form. But as the website states, if you butt to
couplers
together, that will give you a 6 inch form. The couplers are 5 inches at
the
outside edges. By the time the cable is wrapped around it, it's about 6
inches.
I figured that was as close as I could get. As the website mentioned, I
used the
4" PVC pipe as a joint to butt the couplers together, to make them hold
better.
So, I don't know if I used 18-21 feet, but I think I am pretty damn close.

Vinnie S.

I can get 6" pvc. Start with 21 and work my way down till we get the desired
effect.


I have seen 6 inch PVC. It might be too big.

Vinnie S.

Hello DrDeath:

Why do you want a Balun, and on what type installation are you going to
use it????

Jay in the Mojave


DrDeath wrote:
I am trying to build a balun. I chose the one on this web site as I like the
design
http://www.hamuniverse.com/balun.html
It states that, and I quote
"The number of turns is not critical because the inductance depends more on
the length of the wire (coax) than on the number of turns, which will vary
depending on the diameter of the plastic pipe that is used."
But it does not give the formula. It just says 18 to 21 feet.
I plan to use 4 inch pvc and I want to cover as much of the upper 11 meters
as I can. Am I better off at 18 or 21 feet?

"Jay in the Mojave" wrote in message
...
Hello DrDeath:

Why do you want a Balun, and on what type installation are you going to
use it????

Jay in the Mojave


DrDeath wrote:
I am trying to build a balun. I chose the one on this web site as I like
the design
http://www.hamuniverse.com/balun.html
It states that, and I quote
"The number of turns is not critical because the inductance depends more
on the length of the wire (coax) than on the number of turns, which will
vary depending on the diameter of the plastic pipe that is used."
But it does not give the formula. It just says 18 to 21 feet.
I plan to use 4 inch pvc and I want to cover as much of the upper 11
meters as I can. Am I better off at 18 or 21 feet?

I'm just messing around with a home made dipole. I want the balun to cut
down on the TVI.