baluns n chokes n stuff
 

hi

Over the years, I've found it interesting and disturbing even
confusing, that there seems to be so much confusion regarding the
above.

Nothing gets a post responce, like the above topic and boy those
threads quickly grow to large numbers

I always read them trying to learn as well as books on the topics,
i don't pretend to have any formal engineering /scientific
knowledge just enjoy reading what i can

but i ponder why there seems to be so many opposing /contradicting
views on same subjects and topics and i am not referring to just
those here on the news groups

if i get x people in a room ask about baluns or chokes 1/2 say one
thing the other 1/2 say something else

dunno it's strange in all that confusion obviously we all pick
what we interpert and believe to be best but i hate when that happens

baluns n chokes n stuff
 

ml wrote:
dunno it's strange in all that confusion obviously we all pick
what we interpert and believe to be best but i hate when that happens

Baluns are not unique. Religions, politics, investment advice,
brands of vehicles, flavors of ice cream, sexual attraction,
life styles, ... - "We all pick what we interpret and believe
to be the best" in virtually every aspect of our lives.

My personal preference is a 1:1 current-choke-balun with
thousands of ohms of choking impedance, either resistive
and/or reactive.
--
73, Cecil http://www.w5dxp.com

baluns n chokes n stuff
 

"ml" wrote in message
...
hi

Over the years, I've found it interesting and disturbing even
confusing, that there seems to be so much confusion regarding the
above.

Nothing gets a post responce, like the above topic and boy those
threads quickly grow to large numbers

I always read them trying to learn as well as books on the topics,
i don't pretend to have any formal engineering /scientific
knowledge just enjoy reading what i can

but i ponder why there seems to be so many opposing /contradicting
views on same subjects and topics and i am not referring to just
those here on the news groups

if i get x people in a room ask about baluns or chokes 1/2 say one
thing the other 1/2 say something else

dunno it's strange in all that confusion obviously we all pick
what we interpert and believe to be best but i hate when that happens

yeah, i just hate it when that happens... it all stems from many old myths
and misconceptions about what baluns do, or don't do... and confusing them
with coax cable chokes.

One important note... coax IS a balanced transmission line, its just that
the current that balances the one on the center conductor is confined
(normally) to the inside of the shield.

i look at it this way:

a 'true' balun is a transformer that converts from balanced to unbalanced
lines, it may or may not also transform impedances. this is the type of
thing you would put in between a coax and an open wire feeder, or what is
included in many tuners that are fed with coax and have balanced outputs.
in the degenerate case, which is actually now the most common use, the
balanced line is shortened to nothing and the balun is at the feedpoint of
the dipole or yagi driven element.

the coax choke is often confused with a balun because it is also used at a
balanced antenna feedpoint, but the actual physics of it is much different.
if you just connect a dipole to a piece of coax with no choke you really
have a 3 legged 'dipole'. current going out the center conductor wants to
return on the INSIDE of the coax shield... however there are 2 paths for
this current to take. it can come from the other side of the dipole, the
intended path, or it can come from the OUTSIDE of the shield up to the
feedpoint then back to the INSIDE of the shield... this is the one that
causes trouble. Not only is it usually vertically polarized instead of
horizontal like the intended current which distorts the pattern. But it is
also not just confined to the coax near the antenna, it can also exist on
the outside of the shield all the way back to the shack. Now, a choke on
the outside of the shield, either by winding coils of coax or adding ferrite
beads creates a high impedance bump between the shield below the choke and
the inside of the shield at the feed point. This high impedance reflects
any current on the outside of the shield back down, out of phase, thus
effectively canceling it out. This means the only route back for the
current to the inside of the coax shield is from the intended side of the
radiator... thus it forces a balance in the currents, but through a slightly
different mechanism than a 'true' balun transformer. Personally i prefer
the coil method because all it costs is a bit of coax. The ferrites that
are often used can have some unintended effects. first, they are lossy, and
some people assume this is their intended mode of operation and use even
lossier ones than they should. this results in heating at high power and
loss of transmitted power in the choke. also at high power if the cores are
not big enough they can saturate which causes harmonics and even more heat
plus a loss of effectiveness. The more correct way to look at it is as a
single turn choke, the ferrite core should present as high an impedance as
possible with as little loss as possible at the frequency its being used at.
This reduces losses and the associated bad effects. also note that the coax
choke can not transform impedances, the feedpoint must be matched to the
coax.

baluns n chokes n stuff
 

but i ponder why there seems to be so many opposing /contradicting
views on same subjects and topics and i am not referring to just
those here on the news groups

if i get x people in a room ask about baluns or chokes 1/2 say one
thing the other 1/2 say something else

dunno it's strange in all that confusion obviously we all pick
what we interpert and believe to be best but i hate when that happens

It's real easy to get caught up the definitions. A transformer transforms
impedance, voltage or current and often isolates but not necessarily. A
choke uses the magnetic field created by the AC current through it to oppose
that current. The wiki points out there are balanced and unbalanced
signals. Webster says balanced and unbalanced lines. Someone posted that
coax is in fact a balanced line. OK that can be oddly true, but it can be
unbalanced by how you connect it. So it can be part application, part
configuration, part common word usage that might not be purely accurate, and
where you are focusing your attention.

Still, it can be many prefer to be an expert and argue and make statements
rather than ask the questions. I must confess after a project, I often let
details slip by me unlike day to day operations that I can't get out of my
head 30 years later. I can still align Micor and Motrac radios in my sleep
step by step.

The whole discussion could have all been on a roundtable net but then we
wouldn't have the luxury of nit-picking and cussing each other out.

baluns n chokes n stuff
 

Dave wrote:
This means the only route back for the
current to the inside of the coax shield is from the intended side of the
radiator... thus it forces a balance in the currents, but through a slightly
different mechanism than a 'true' balun transformer.

Sevick suggested that the word transformer *NOT* be used
with baluns. He said, in "Building and Using Baluns and
Ununs":

"By far, most misconceptions regarding baluns are due
to the many radio amateurs who perceive these devices
as conventional transformers that transmit the energy
from input to output by flux linkages and not as
transmission line transformers, which transmit energy
by an efficient transmission line mode."

"If the writers had accepted the correct model for
these devices (given to us by Guanella and Ruthroff),
which shows that *THEY ARE REALLY CHOKES* (lumped
elements) and configurations of transmission lines
(distributed elements), ..." emphasis mine.

"In fact, the perception that the transmission line
transformer is actually a conventional transformer
is so prevalent, that a new name for this class of
devices should be considered -
*broad band transmission line matching networks*.
This name (without the word transformer) would help
in dispelling inaccurate perceptions and in
standardizing the schematic diagrams."
--
73, Cecil http://www.w5dxp.com

baluns n chokes n stuff
 

JB wrote:
I can still align Micor and Motrac radios in my sleep
step by step.

Using megacycles and condensers, no doubt. :-)
--
73, Cecil http://www.w5dxp.com

baluns n chokes n stuff
 

On Fri, 05 Sep 2008 08:56:34 -0400, ml wrote:

but i ponder why there seems to be so many opposing /contradicting
views on same subjects and topics and i am not referring to just
those here on the news groups

Hi Myles,

Most of this "controversy" extends from the lack of experience. Quite
a natural condition for some amateurs. This will change if they are
interested - interest also being a common condition for amateurs.

Those with a technical bent (rather than simply being interested in
operating) will sit at the bench and figure out this topic of baluns n
chokes n stuff. Then it won't be the controversial mystery it seems
to be for those who don't.

73's
Richard Clark, KB7QHC

baluns n chokes n stuff
 

ml wrote:
hi

Over the years, I've found it interesting and disturbing even
confusing, that there seems to be so much confusion regarding the
above.

Nothing gets a post responce, like the above topic and boy those
threads quickly grow to large numbers

I always read them trying to learn as well as books on the topics,
i don't pretend to have any formal engineering /scientific
knowledge just enjoy reading what i can

but i ponder why there seems to be so many opposing /contradicting
views on same subjects and topics and i am not referring to just
those here on the news groups


Several reasons..
1) the terminology isn't necessarily consistent in its definition

2) the things get used in a complex system with lots of interactions, so
it's hard to separate out the effects of the function of component A
from those of components B,C,D, and E.

3) there's a host of empirical evidence out there that seems to
contradict the theoretical behavior of A (mostly because the empirical
evidence also includes the behaviors of B, C, D, and E, which aren't
always controlled for or understood). So you wind up with "A does X" in
system 1, and "A does Y" in system 2.

baluns n chokes n stuff
 

"Cecil Moore" wrote in message
...
JB wrote:
I can still align Micor and Motrac radios in my sleep
step by step.

Using megacycles and condensers, no doubt. :-)
--
73, Cecil http://www.w5dxp.com

Those were in the Pre-Progs.

baluns n chokes n stuff
 

In article ,
Cecil Moore wrote:

ml wrote:
dunno it's strange in all that confusion obviously we all pick
what we interpert and believe to be best but i hate when that happens

Baluns are not unique. Religions, politics, investment advice,
brands of vehicles, flavors of ice cream, sexual attraction,
life styles, ... - "We all pick what we interpret and believe
to be the best" in virtually every aspect of our lives.

My personal preference is a 1:1 current-choke-balun with
thousands of ohms of choking impedance, either resistive
and/or reactive.

wanted to say thanks much to all those that responded really
appreciate the thoughts

i guess for me, the 'easy ' way out (when in doubt) is after i do
something to take measurements, if i dont see what i should i
presume i did it wrong,

never hurts to double check with testing or to buy test gear and
tools

thanks again all

baluns n chokes n stuff
 

On 5 sep, 14:56, ml wrote:
hi

Over the years, I've found it interesting and disturbing even
confusing, that there seems to be so much confusion regarding the
above.

Nothing gets a post responce, like the above topic and boy those
threads quickly grow to large numbers

I always read them trying to learn as well as books on the topics,
i don't pretend to have any formal engineering /scientific
knowledge just enjoy reading what i can

but i ponder why there seems to be so many opposing /contradicting
views on same subjects and topics and i am not referring to just
those here on the news groups

if i get x people in a room ask about baluns or chokes 1/2 say one
thing the other 1/2 say something else

dunno it's strange in all that confusion obviously we all pick
what we interpert and believe to be best but i hate when that happens

Hello ML,

Is it really opposing /contradicting or just different?

Most baluns (in antenna systems) are used to make sure that the
current in the antenna structure is far higher then the common mode
current in the feedline.
Common mode current = Icenter + Iscreen.

To say in other words: function of balun is to make sure that the feed
line does not take part in the radiation process.

Some issues that may affect the type and actual design of the balun:

1. "far higher" (how good it mist be) is not a hard figure and depends
on the application. Requirements for a field day will be different
then for an EMC measuring antenna in an anechoic chamber.

2. The behavior of the balun depends on the impedance levels (both
common mode and differential mode) on both balanced and unbalanced
side. A balun for a full wave dipole "receives" more voltage stress
than a dipole for a HW dipole (at same power level).

3. A balun can be narrow band and wide band (ferrite core baluns
[wide] versus resonating transmission line [narrow]).

4. Some baluns have the function to generate two opposite voltages
with respect to another point (even when the load is not fully
balanced [for example in electronic circuits]).

5. Financial issues may play a role (especially in mass volume
products). A balun on PCB is far cheaper than a coaxial one with
ferrite cores.

6. How much insertion / mismatch loss is allowed, what about power
handling?

Just by mentioning 6 points, you can imagine that a certain balun does
perform well in application A, but not in application B. A wrong type
of balun for a certain application may even make the situation worse
(while that balun is OK for another application).

Like Cecil, when 1:1 impedance is OK up to VHF, I prefer the current
choke balun (the one with the ferrite cores). If possible with low Q
factor for the common mode inductance.

For the upper UHF and SHF, performance of ferrite ceases and other
types (like shorted quarter wave sections or tapered lines) can be
used.

As there are many varieties, two poeple may say different things, but
they are both right.

Best regards,

Wim
PA3DJS
www.tetech.nl
the address is OK but don't forget to remove abc

baluns n chokes n stuff
 

On Sun, 7 Sep 2008 06:54:49 -0700 (PDT), Wimpie
wrote:

Most baluns (in antenna systems) are used to make sure that the
current in the antenna structure is far higher then the common mode
current in the feedline.
Common mode current = Icenter + Iscreen.

Hi Wim,

I presume "screen" is the coax shield. If there is any Common Mode
current, it is going to reside on the outside of the shield in a
different degree than inside the shield where it will be combined with
Differential Mode current.

In fact it would be simpler to measure it there too.

To say in other words: function of balun is to make sure that the feed
line does not take part in the radiation process.

Only if the BalUn is designed with choking properties, otherwise it
will make no difference at all in feed line radiation. To quickly
summarize from popular labels, you have Current BalUns and Voltage
Baluns. Such labels differentiate those that choke and those that do
not, but they are often misapplied and represent no real guarantee.
The informed buyer should always examine the construction details.

Some issues that may affect the type and actual design of the balun:

1. "far higher" (how good it mist be) is not a hard figure and depends
on the application. Requirements for a field day will be different
then for an EMC measuring antenna in an anechoic chamber.

This is an unusual issue. There is no correlation to need and
frequency. There is no correlation to application and frequency.
Motivation may even dictate you ignore chokes and BalUns altogether
during field day for simplicity's sake. If you demand performance,
then all the rules of choking and BalUn application apply at all
frequencies.

2. The behavior of the balun depends on the impedance levels (both
common mode and differential mode) on both balanced and unbalanced
side. A balun for a full wave dipole "receives" more voltage stress
than a dipole for a HW dipole (at same power level).

The point of a BalUn is to transform from the source Z to the load Z.
If the load Z happens to be high, you select a BalUn with its ratio
designed appropriately. Hence the variety of ratios as no single
design is appropriate at all frequencies for a single antenna. Voltage
(or current) stress is part of the design criteria, not a limitation
to its application.

5. Financial issues may play a role (especially in mass volume
products). A balun on PCB is far cheaper than a coaxial one with
ferrite cores.

This point, and two before it (not quoted here) seem to speak to small
signal, board level applications. They have no application with
antennas. For instance, no one is going to find any application for a
BalUn on a PCB (for which I see no distinction) unless the antenna is
also on the PCB.

6. How much insertion / mismatch loss is allowed, what about power
handling?

BalUns that are appropriately selected to the load have a far greater
chance of performing without issue than many other matching solutions.
Consider the insertion loss of a typical, external tuner compared to
that of a BalUn that satisfies the same mismatch. I suspect you will
probably lose far more power in the tuner, or at best achieve parity
with the BalUn. This is not to say that a BalUn solves all problems
and is the universal solution, however.

I prefer the current
choke balun (the one with the ferrite cores). If possible with low Q
factor for the common mode inductance.

In fact, the 1:1 Choke BalUn has very little inductance to offer, and
some formulations of ferrite may even present a minor capacitive
reactance. The major characteristic of ferrite is Resistance, and it
is the resistance that offers the isolation (choking) from input to
output.

73's
Richard Clark, KB7QHC

baluns n chokes n stuff
 

Hello Richard,

Please find comment under your text.

On 7 sep, 18:29, Richard Clark wrote:
On Sun, 7 Sep 2008 06:54:49 -0700 (PDT), Wimpie
wrote:

Most baluns (in antenna systems) are used to make sure that the
current in the antenna structure is far higher then the common mode
current in the feedline.
Common mode current = Icenter + Iscreen.

Hi Wim,

I presume "screen" is the coax shield.

Correct.

If there is any Common Mode
current, it is going to reside on the outside of the shield in a
different degree than inside the shield where it will be combined with
Differential Mode current.

In fact it would be simpler to measure it there too.

For cable with solid screen, Iscreen = I_inner + I_outer.
To go in more detail (I thought) was not relevant for the original
question.
For radiation, and distance between currents WL, only common mode
current counts (and you can measure that with a current probe).


To say in other words: function of balun is to make sure that the feed
line does not take part in the radiation process.

Only if the BalUn is designed with choking properties, otherwise it
will make no difference at all in feed line radiation. To quickly
summarize from popular labels, you have Current BalUns and Voltage
Baluns. Such labels differentiate those that choke and those that do
not, but they are often misapplied and represent no real guarantee.
The informed buyer should always examine the construction details.

A fully balanced load can be connected to an unbalanced feed line with
a voltage balun (for example center tapped transformer), a choking
type balun is not necessary for this. So I do not agree on your
point.


Some issues that may affect the type and actual design of the balun:

1. "far higher" (how good it mist be) is not a hard figure and depends
on the application. Requirements for a field day will be different
then for an EMC measuring antenna in an anechoic chamber.

This is an unusual issue. There is no correlation to need and
frequency. There is no correlation to application and frequency.
Motivation may even dictate you ignore chokes and BalUns altogether
during field day for simplicity's sake. If you demand performance,
then all the rules of choking and BalUn application apply at all
frequencies.

Did I mention frequency under point 1? I ment to say that requirements
for the balun (how good it must be) depends on your application. For a
field day you may ignore the balun function at all (you may burn your
fingers), but for an Antenna Range, you need a good one with high
common mode attenuation (when you use a balanced reference antenna).


2. The behavior of the balun depends on the impedance levels (both
common mode and differential mode) on both balanced and unbalanced
side. A balun for a full wave dipole "receives" more voltage stress
than a dipole for a HW dipole (at same power level).

The point of a BalUn is to transform from the source Z to the load Z.
If the load Z happens to be high, you select a BalUn with its ratio
designed appropriately. Hence the variety of ratios as no single
design is appropriate at all frequencies for a single antenna. Voltage
(or current) stress is part of the design criteria, not a limitation
to its application.

Impedance transformation is a "byproduct", main function is to couple
balanced circuit to unbalanced circuit without feed line radiation.
The stress applied to the balun depends on the impedance level. I
mentioned this to show that even with dipoles (and same power) you can
have different designs (or size). Yes, a choke type balun that can
handle max. 1kW into a HW dipole, will probably run hot (or flashes
over) when used on a thin FW dipole with same input power.


5. Financial issues may play a role (especially in mass volume
products). A balun on PCB is far cheaper than a coaxial one with
ferrite cores.

This point, and two before it (not quoted here) seem to speak to small
signal, board level applications. They have no application with
antennas. For instance, no one is going to find any application for a
BalUn on a PCB (for which I see no distinction) unless the antenna is
also on the PCB.

I designed some PCB baluns for feeding PCB antennas and wire antennas
connected to the (tiny) PCB, because of ease of production (no other
handwork required). They perform not as good as a coaxial type, but
good enough for the application.


6. How much insertion / mismatch loss is allowed, what about power
handling?

BalUns that are appropriately selected to the load have a far greater
chance of performing without issue than many other matching solutions.
Consider the insertion loss of a typical, external tuner compared to
that of a BalUn that satisfies the same mismatch. I suspect you will
probably lose far more power in the tuner, or at best achieve parity
with the BalUn. This is not to say that a BalUn solves all problems
and is the universal solution, however.

I prefer the current
choke balun (the one with the ferrite cores). If possible with low Q
factor for the common mode inductance.

In fact, the 1:1 Choke BalUn has very little inductance to offer, and
some formulations of ferrite may even present a minor capacitive
reactance. The major characteristic of ferrite is Resistance, and it
is the resistance that offers the isolation (choking) from input to
output.

This depends on the type of ferrite, frequency and final geometry of
the balun. Although not preferred (possible change on parasitic
resonance with capacitive common mode impedance), an inductive common
mode choking action can provide good isolation (as long as reactance
is high enough with respect to the impedance at the balanced side).
For JOTA I use a choke type balun that is inductive (with low Q
factor) for 80m, while it is almost resistive for 40m.

73's
Richard Clark, KB7QHC

Richard, I only wanted to make clear that there are many solutions for
the same problem and that one solution cannot fit all problems. It was
not my purpose to be complete.

Best regards,

Wim
PA3DJS
www.tetech.nl
without abc, the address is correct.

baluns n chokes n stuff
 

ml wrote:
[balun stuff]

Seen this page:

http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=7840

author, page owner, claims it was first designed by the collins co. A
few more turns and you could use it on the AM Broadcast band of your
general coverage receiver ...

Regards,
JS

baluns n chokes n stuff How not to choke when doing thedeed by John Smith
 

John Smith wrote:
On Sep 13, 2:12 pm, John Smith wrote:
ml wrote:

Like it or not, your going to hear about my sex life with the wife and I and the neighbors dog!

I do not choke, I have too many years of experience deepthroating to choke. I taught my wife all there is to know about deepthroating and not choking.


I can deep throat with the best of them
I can handle anyones meat, bring it on
I do it all, and what I can;t my wife will take care of...

Regards,
JS


The above is a post from a particularly sick/mentally-ill individual,
information on his IP follows:

dialup-4.255.240.79.Dial1.Atlanta1.Level3.net

Whois information on 4.255.240.79:

OrgName: Level 3 Communications, Inc.
OrgID: LVLT
Address: 1025 Eldorado Blvd.
City: Broomfield
StateProv: CO
PostalCode: 80021
Country: US

NetRange: 4.0.0.0 - 4.255.255.255
CIDR: 4.0.0.0/8
NetName: LVLT-ORG-4-8
NetHandle: NET-4-0-0-0-1
Parent:
NetType: Direct Allocation
NameServer: NS1.LEVEL3.NET
NameServer: NS2.LEVEL3.NET
Comment:
RegDate:
Updated: 2004-06-04

OrgAbuseHandle: APL8-ARIN
OrgAbuseName: Abuse POC LVLT
OrgAbusePhone: +1-877-453-8353
OrgAbuseEmail:

OrgTechHandle: ARINC4-ARIN
OrgTechName: ARIN Contact
OrgTechPhone: +1-800-436-8489
OrgTechEmail:

OrgTechHandle: TPL1-ARIN
OrgTechName: Tech POC LVLT
OrgTechPhone: +1-877-453-8353
OrgTechEmail:

# ARIN WHOIS database, last updated 2008-09-13 19:10
# Enter ? for additional hints on searching ARIN's WHOIS database.

There is an email for reporting abuse in the above data. An email to
them, with the date, time and nature of the abusive text (indeed, a
quote of his text should make the point clear) should certainly gain the
attention of the ISP. As, I don't think they would like their system
involved in such insane behaviors of psychotic individual ...

Just in case you tire of this fool and think the administrators of his
ISP may feel likewise ...

Regards,
JS

baluns n chokes n stuff How not to choke when doing the deedby John Smith
 

On Sep 14, 11:25*am, John Smith wrote:
John Smith wrote:
On Sep 13, 2:12 pm, John Smith wrote:
ml wrote:

Like it or not, your going to hear about my sex life with the wife and I and the neighbors dog!

I do not choke, I have too many years of experience deepthroating to choke. I taught my wife all there is to know about deepthroating and not choking.

I can deep throat with the best of them
I can handle anyones meat, bring it on
I do it all, and what I can;t my wife will take care of...

Regards,
JS

The above is a post from a particularly sick/mentally-ill individual,
information on his IP follows:

dialup-4.255.240.79.Dial1.Atlanta1.Level3.net

Whois information on 4.255.240.79:

OrgName: * *Level 3 Communications, Inc.
OrgID: * * *LVLT
Address: * *1025 Eldorado Blvd.
City: * * * Broomfield
StateProv: *CO
PostalCode: 80021
Country: * *US

NetRange: * 4.0.0.0 - 4.255.255.255
CIDR: * * * 4.0.0.0/8
NetName: * *LVLT-ORG-4-8
NetHandle: *NET-4-0-0-0-1
Parent:
NetType: * *Direct Allocation
NameServer: NS1.LEVEL3.NET
NameServer: NS2.LEVEL3.NET
Comment:
RegDate:
Updated: * *2004-06-04

OrgAbuseHandle: APL8-ARIN
OrgAbuseName: * Abuse POC LVLT
OrgAbusePhone: *+1-877-453-8353
OrgAbuseEmail:

OrgTechHandle: ARINC4-ARIN
OrgTechName: * ARIN Contact
OrgTechPhone: *+1-800-436-8489
OrgTechEmail:

OrgTechHandle: TPL1-ARIN
OrgTechName: * Tech POC LVLT
OrgTechPhone: *+1-877-453-8353
OrgTechEmail:

# ARIN WHOIS database, last updated 2008-09-13 19:10
# Enter ? for additional hints on searching ARIN's WHOIS database.

There is an email for reporting abuse in the above data. *An email to
them, with the date, time and nature of the abusive text (indeed, a
quote of his text should make the point clear) should certainly gain the
attention of the ISP. *As, I don't think they would like their system
involved in such insane behaviors of psychotic individual ...

Just in case you tire of this fool and think the administrators of his
ISP may feel likewise ...

Regards,
JS- Hide quoted text -

- Show quoted text -

baaaaaaaaaaaaaaaahahhhhhhhhhaaaaaaaaaaaaaaa you twit!