Choke baluns again
 

A choke balun is what is inserted between the transmitter end of the
antenna feedline and the transmitte tuner. Or it can be inserted at
the antenna end of the line.

Questions : How effective is it? To what extent can the percentage
unbalance current on the feedline be expected to be reduced? Has
anybody ever measured it before and after insertion?
----
Reg.

Reg:

I can comment on my recent experiments with a half-wave vertical on
10-11 meters.

A current balun (or ferrite beads on the coax) greatly reduce feedline
radiation--seems to have an overall beneficial effects on the antennas
radiation pattern--and seems to "stabilize" the pruning/tuning of the
antenna (things begin behaving in a linear and logical way.)

Mind you, the above is only deduced/measured with a FSM, SWR bridge (of
the type which does NOT work for real measurement of swr but rather
transmitter loading) and observed/known signals from other stations and
the reports given back on my signal from these stations.

While this may be viewed as "crude" by some--it is real world in that
the effects as least "seem" real.

Or, the short form of all this is, "The Current Balun is my friend!"

John

"Reg Edwards" wrote in message
...
A choke balun is what is inserted between the transmitter end of the
antenna feedline and the transmitte tuner. Or it can be inserted at
the antenna end of the line.

Questions : How effective is it? To what extent can the percentage
unbalance current on the feedline be expected to be reduced? Has
anybody ever measured it before and after insertion?
----
Reg.

.... I should have pointed out, always, the balun has been inserted at
the antenna, and never at the transmitter end of the coax in my previous
post...

John

"John Smith" wrote in message
...
Reg:

I can comment on my recent experiments with a half-wave vertical on
10-11 meters.

A current balun (or ferrite beads on the coax) greatly reduce feedline
radiation--seems to have an overall beneficial effects on the antennas
radiation pattern--and seems to "stabilize" the pruning/tuning of the
antenna (things begin behaving in a linear and logical way.)

Mind you, the above is only deduced/measured with a FSM, SWR bridge
(of the type which does NOT work for real measurement of swr but
rather transmitter loading) and observed/known signals from other
stations and the reports given back on my signal from these stations.

While this may be viewed as "crude" by some--it is real world in that
the effects as least "seem" real.

Or, the short form of all this is, "The Current Balun is my friend!"

John

"Reg Edwards" wrote in message
...
A choke balun is what is inserted between the transmitter end of the
antenna feedline and the transmitte tuner. Or it can be inserted at
the antenna end of the line.

Questions : How effective is it? To what extent can the percentage
unbalance current on the feedline be expected to be reduced? Has
anybody ever measured it before and after insertion?
----
Reg.

.... yes, I am known to reply to my own posts--far too often...

From all the current baluns I have tried, and I have tried every type I
could find, this choke/balun design is my favorite and seems to have the
lowest insertion loss of all and seems to exhibit excellent qualities of
the type desired:
http://home.datacomm.ch/hb9abx/pactor-e-choke.htm

John

"John Smith" wrote in message
...
... I should have pointed out, always, the balun has been inserted at
the antenna, and never at the transmitter end of the coax in my
previous post...

John

"John Smith" wrote in message
...
Reg:

I can comment on my recent experiments with a half-wave vertical on
10-11 meters.

A current balun (or ferrite beads on the coax) greatly reduce
feedline radiation--seems to have an overall beneficial effects on
the antennas radiation pattern--and seems to "stabilize" the
pruning/tuning of the antenna (things begin behaving in a linear and
logical way.)

Mind you, the above is only deduced/measured with a FSM, SWR bridge
(of the type which does NOT work for real measurement of swr but
rather transmitter loading) and observed/known signals from other
stations and the reports given back on my signal from these stations.

While this may be viewed as "crude" by some--it is real world in that
the effects as least "seem" real.

Or, the short form of all this is, "The Current Balun is my friend!"

John

"Reg Edwards" wrote in message
...
A choke balun is what is inserted between the transmitter end of the
antenna feedline and the transmitte tuner. Or it can be inserted at
the antenna end of the line.

Questions : How effective is it? To what extent can the percentage
unbalance current on the feedline be expected to be reduced? Has
anybody ever measured it before and after insertion?
----
Reg.

The only thing I have against them (current baluns) is
They are heavy.
and cause the antenna to droop
lowering the height of the feedpoint.
Which is a good reason to put the balun near the radio and use balanced
feedline from there to the antenna
my 3.5 cents


"John Smith" wrote in message
...
... yes, I am known to reply to my own posts--far too often...

From all the current baluns I have tried, and I have tried every type I
could find, this choke/balun design is my favorite and seems to have the
lowest insertion loss of all and seems to exhibit excellent qualities of
the type desired:
http://home.datacomm.ch/hb9abx/pactor-e-choke.htm

John

"John Smith" wrote in message
...
... I should have pointed out, always, the balun has been inserted at
the antenna, and never at the transmitter end of the coax in my
previous post...

John

"John Smith" wrote in message
...
Reg:

I can comment on my recent experiments with a half-wave vertical on
10-11 meters.

A current balun (or ferrite beads on the coax) greatly reduce
feedline radiation--seems to have an overall beneficial effects on
the antennas radiation pattern--and seems to "stabilize" the
pruning/tuning of the antenna (things begin behaving in a linear and
logical way.)

Mind you, the above is only deduced/measured with a FSM, SWR bridge
(of the type which does NOT work for real measurement of swr but
rather transmitter loading) and observed/known signals from other
stations and the reports given back on my signal from these stations.

While this may be viewed as "crude" by some--it is real world in that
the effects as least "seem" real.

Or, the short form of all this is, "The Current Balun is my friend!"

John

"Reg Edwards" wrote in message
...
A choke balun is what is inserted between the transmitter end of the
antenna feedline and the transmitte tuner. Or it can be inserted at
the antenna end of the line.

Questions : How effective is it? To what extent can the percentage
unbalance current on the feedline be expected to be reduced? Has
anybody ever measured it before and after insertion?
----
Reg.

On Sun, 26 Jun 2005 14:19:30 -0400, "Hal Rosser"
wrote:

The only thing I have against them (current baluns) is
They are heavy.
and cause the antenna to droop
lowering the height of the feedpoint.
Which is a good reason to put the balun near the radio and use balanced
feedline from there to the antenna
my 3.5 cents


I just weighed 50 beads that are used in W2DU's balun and came up with
a whopping 4 ounces!

Yea, four ounces should cause one hell of a droop.G

73,
Danny, K6MHE

Dan:
"Droop?"

Hmm, I have heard about that, brits may refer to it as "brewers droop?"
Or, maybe I am confused here...

However, problem only seems to occur when there are pints involved...
grin

John

"Dan Richardson arrl net" k6mheatdot wrote in message
...
On Sun, 26 Jun 2005 14:19:30 -0400, "Hal Rosser"
wrote:

The only thing I have against them (current baluns) is
They are heavy.
and cause the antenna to droop
lowering the height of the feedpoint.
Which is a good reason to put the balun near the radio and use
balanced
feedline from there to the antenna
my 3.5 cents


I just weighed 50 beads that are used in W2DU's balun and came up with
a whopping 4 ounces!

Yea, four ounces should cause one hell of a droop.G

73,
Danny, K6MHE

Dan Richardson k6mheatarrl wrote:
Yea, four ounces should cause one hell of a droop.G

Droop is like dB loss - it should be minimized at all costs. :-)
--
73, Cecil http://www.qsl.net/w5dxp

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Reg Edwards wrote:
A choke balun is what is inserted between the transmitter end of the
antenna feedline and the transmitte tuner. Or it can be inserted at
the antenna end of the line.

Questions : How effective is it? To what extent can the percentage
unbalance current on the feedline be expected to be reduced? Has
anybody ever measured it before and after insertion?

Yep, and you'll find it right on the web. Go to
http://eznec.com/Amateur/Articles/Baluns.pdf and read the section titled
"Experiments" beginning on p. 3 of the PDF document. You might also find
some other interesting information in this article.

Warning, though. It was written by an American, so should be regarded
with great suspicion and skepticism.

Roy Lewallen, W7EL

Reg:

As usual, your posts inspire thought--and that is a GOOD thing.

At least with this type of balun:
http://home.datacomm.ch/hb9abx/pactor-e-choke.htm

I ask, "Why not?" The insertion loss is negligible. The downside of
its' use is virtually none. The upside is that in the future, as
objects may come into the field close enough to couple with the antenna,
or corrosion-weather-"stretch"-age-"or other factors begin to cause
slight imbalances-- the balun steps in and begins enforcing a "balance."

It just seems one would error on the side of caution and use such a
balun. I know of few better examples of a "win-win situation."

Indeed, the article Roy offered seems like one heck of an argument to
this end...

.... certainly someone not prepared to weigh the "fly chit" they have
picked out of the pepper should just chuck one in the line and rest
assured "it is a good thing."

Warmest regards,
John

"Reg Edwards" wrote in message
...
A choke balun is what is inserted between the transmitter end of the
antenna feedline and the transmitte tuner. Or it can be inserted at
the antenna end of the line.

Questions : How effective is it? To what extent can the percentage
unbalance current on the feedline be expected to be reduced? Has
anybody ever measured it before and after insertion?
----
Reg.