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.

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?

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.

"DrDeath" wrote in message
...
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 and it does a great job of keeping feedline currents down, no
more RF in the shack. Iwas having problems regardless of grounding. Here's
some pics. If you want inside detail I have pics of that too.

http://i6.photobucket.com/albums/y23...f/HPIM1678.jpg

http://i6.photobucket.com/albums/y23...f/HPIM1676.jpg

http://i6.photobucket.com/albums/y23...f/HPIM1666.jpg


Chad

On Tue, 10 Jan 2006 09:08:03 -0600, "Chad Wahls" wrote:


"DrDeath" wrote in message
...
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 and it does a great job of keeping feedline currents down, no
more RF in the shack. Iwas having problems regardless of grounding. Here's
some pics. If you want inside detail I have pics of that too.

http://i6.photobucket.com/albums/y23...f/HPIM1678.jpg

http://i6.photobucket.com/albums/y23...f/HPIM1676.jpg

http://i6.photobucket.com/albums/y23...f/HPIM1666.jpg



Great pics. What kind of symptoms were you experiencing?

Vinnie S.

"Vinnie S." wrote in message
...
On Tue, 10 Jan 2006 09:08:03 -0600, "Chad Wahls" wrote:


"DrDeath" wrote in message
...
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 and it does a great job of keeping feedline currents down, no
more RF in the shack. Iwas having problems regardless of grounding.
Here's
some pics. If you want inside detail I have pics of that too.

http://i6.photobucket.com/albums/y23...f/HPIM1678.jpg

http://i6.photobucket.com/albums/y23...f/HPIM1676.jpg

http://i6.photobucket.com/albums/y23...f/HPIM1666.jpg



Great pics. What kind of symptoms were you experiencing?

Vinnie S.

My radio room is also an electronics repair area. The test equipment would
act erratic at best during transmit, meters would peg, you could see carrier
or SSB voice on the scope, etc. The power supply intended for the radio
would go into current limit even though there was a lot more on tap
(acopian). Before grounding extensively I got a couple RF nips, not cool.
I was also having problems with the shop stereo (mainly the unbalanced link
between the Phase Linear amp and Onkyo preamp) and speakers in the house
attached to cheapo soundcards. I'm not running mondo power either.

I modified the balun design a tad to accommodate the weird Illinois weather
and facilitate removal if it did not work as expected. All the stuff was
made from scrap I had laying around.

ALL RF problems associated with feedline radiation went away, the test gear
sees nothing. The power supply works well when needed (I run battery/solar
power) and there is no nipping at all. This even works when lifting grounds
as a test.

The problem with the audio equipment is still there, I'm sure it is do to
the antenna being lower than optimal and ****ty soundcard grounds. All
things to be fixed in time. Incidentally the audio computer with pro gear
attached has no problems with interference and is closer to the radiator in
height and proximity. Good grounding has paid off there, there is no noise
problems and there is an assload of power there on that system, both SS and
tube.

So a long story short: It did not solve all my problems but made a very
noticeable improvement around sensitive equipment. I have noticed NO
sacrifice in transmit or receive strength. If you can build one for free or
next to nothing I think it's a good idea to try.

Chad