9:1 Balun

classic Classic list List threaded Threaded
27 messages Options
12
Reply | Threaded
Open this post in threaded view
|

9:1 Balun

Elecraft mailing list
What are the advantages/disadvantages of using a 9:1 balun v. using the switchable Elecraft balun at 1:1 or 4:1 or no balun at all when using a random wire portable?
Why 9:1?
Thanks 
73 Eric WD6DBM


Sent on my Samsung Galaxy S® 6.
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

Thomas Horsten
Depends on your random wire and what band(s) you want to use. For some
bands the 9:1 "balun" (not used as a true balun in this case, since both
the coax and the random wire are unbalanced by nature) will step the
feedpoint impedance down to something that's a better match for the 50 ohm
coax, limiting coax losses. It can also allow your ATU to tune up on
frequencies otherwise outside its range. Use the "balun" with a
counterpoise or earth.

In some cases the 4:1 or 1:1 balun may be a better choice, or even
connecting the wire directly to the coax center conductor (and counterpoise
to the shield). All depends on QRG and wire length. If the ATU can tune it
up, you're good to go, if not, change one or more parameters until it can
(wire length, balun ratio, counterpoise length and orientation).

For more information read Dale WB6BYU's answer here:
http://www.eham.net/ehamforum/smf/index.php?topic=33274.0;wap2

73, Thomas OZ5TN

On 31 January 2017 at 07:59, gliderboy1955 via Elecraft <
[hidden email]> wrote:

> What are the advantages/disadvantages of using a 9:1 balun v. using the
> switchable Elecraft balun at 1:1 or 4:1 or no balun at all when using a
> random wire portable?
> Why 9:1?
> Thanks
> 73 Eric WD6DBM
>
>
> Sent on my Samsung Galaxy S® 6.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

Joe Subich, W4TV-4

On 1/31/2017 3:43 AM, Thomas Horsten wrote:
> Depends on your random wire and what band(s) you want to use. For
> some bands the 9:1 "balun" (not used as a true balun in this case,
> since both the coax and the random wire are unbalanced by nature)
> will step the feedpoint impedance down to something that's a better
> match for the 50 ohm coax, limiting coax losses.

Unless one is using a matching device designed as a current balun,
the common 4:1 and 9:1 "baluns" are actually simple auto-transformers.

The best approach is an auto-transformer at the feedpoint (with a
counterpoise) followed by a true 1:1 current balun (common mode
choke).

The 9:1 "balun"/transformer may be more appropriate if the "wire"
approaches a half wave on the frequencies of interest.  However,
there is a definite interaction among antenna length, transformer
ratio, feedline impedance and feedline length.

73,

    ... Joe, W4TV


______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

NJ8M
In reply to this post by Elecraft mailing list
Be careful in the 9 to 1 vs 4 to 1 vs 1 to 1. The 9:1 is generally an UNUN.
When you run 100 watts or less most 1kw manufactured baluns or Ununs will
take a wide variety of SWR if you are only running 100 watts. Because this
thread is I believe about QRP the amount of power dissipated due to loss is
not a factor. When you jump to 500 watts, core heating, saturation and
breakdown are a risk.

For instance, the W2AU balun that is manufactured as a center feed point
for a dipole is only rated for the power at 1:1 SWR. In the printed
literature the power rating drops off considerable as one goes to 2:1. I
have personal experience with this particular balun when an 80/40 trap
dipole was constructed using that balun and the Unadalla KW40 traps.
Operating 40 was no problem as it was nearly 1:1 anywhere we operated [CW],
but on 80 CW the bandwidth was much narrower, as to be expected and nearing
the edges when we ran 500 watts into the antenna with the balun rated at
1kw, well, it's core heated up, SWR drastically changed, heating the core
windings so much that the solder to the SO239 connecting the core to the
coax melted off. We knew that the SWR was between 2.5-3:1 on the edges of
the 80 meter range. So be careful. Additionally, I have little faith in
stick Baluns or Ununs, I personally do not believe they are nearly as good
as a Toroid constructed balun.

Ununs seem to in my experience, tolerate wide ranges in SWR. I have used a
9:1 unun and their new 52:1 transformer for end fed antennas  manufactured
by Balundesigns.com with excellent results running 800 watts CW with little
or no heating of the core and consistent results in a multiband
environment. This was done using a 43, 53 and 87 foot end fed
vertical/random wire/ inverted L and Half Square configurations. I have not
modeled the pattern with NEC but I have compared it on Reverse Beacon
Network [RBN] and I am definitely getting out. Full well knowing that Non
resonant antennas are not as good as resonant ones, yes there is a
difference in RBN reporting which favors the resonant, but, not always.
This is because there is "funky lobe radiation"  that can give a high
report to just random one or two reporting stations and then the rest are
10-15 db less than the resonant over a wider area of report stations. This
supports the pattern is not predictable, or as predictable as a resonant
antenna installed correctly. Knowing we are addressing compromise
installation for multiband usage, this I believe is acceptable. If you have
goals of working or covering with gain and directivity, then there is no
replacement for well designed and well installed resonant antennas. This is
especially true in the competitive environment of contesting.

When an antenna that is not balanced is used, the RF will seek a way to
ground. Problems with feed line radiation, and RF in the shack are
problematic. Using a counterpoise or limited radial system is recommended
to provide the missing balance and a path to ground. This is generally not
a problem at QRP levels but because a few 100 miliwatts  of power coming
back to the shack does not cause much problems but, jump that up to 10 or
100 watts and problems will surely make your life a living hell trying to
keep the computer, keyboard, mouse cables connected and ATU from resetting
and starting tuning cycle again and again. Best solution is to run resonant
balanced antennas if one can, if one can't, invest in a few line isolators
for the coax before it hits the shack and then have a good stock of Mix 31
ferrite beads for each cable in the shack, eg, usb, keyer, mic, speaker,
keyboard, mouse...you get the idea.

In the end, when one runs QRP power, balun/unun saturation and performance
degradation, allows most anything to fly, jump the power to 100 watts,
watch out, then to 800 watts...reforming injection formed plastic is in
your future. Although, relative to this discussion,  making an unun or
balun with a T25 core and 32gauge wire will most likely produce the same
disasterous results with 10 watts. LOL.

Finally, Any antenna is better than No antenna.

Morgan NJ8M

On Tue, Jan 31, 2017 at 12:59 AM, gliderboy1955 via Elecraft <
[hidden email]> wrote:

> What are the advantages/disadvantages of using a 9:1 balun v. using the
> switchable Elecraft balun at 1:1 or 4:1 or no balun at all when using a
> random wire portable?
> Why 9:1?
> Thanks
> 73 Eric WD6DBM
>
>
> Sent on my Samsung Galaxy S® 6.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

David Bunte
In reply to this post by Joe Subich, W4TV-4
I have limited experience with a wire fed via a 9:1 "un-un", but that
experience was VERY good.

I borrowed a KX3 from a friend when I went to visit family in FL a few
years ago. I had a 9:1 "un-un", about 126' of wire, and 50 feet of RG8-X. I
got the feedpoint, up 30 feet into a tree, and the far end over limb of
another tree. That point was about 15 feet above ground. About 7 feed of
the wire hung straight down toward the ground. I used a 30 foot
counterpoise, that hung down from the "un-un", along with the coax.

I did not try 160 (this was in mid-summer), but the ATU in the KX3 achieved
a good enough match on 80 through 10 meters... and I made a few hundred
QSOs, including some nice long rag chews, and 68 countries in just shy of 3
weeks. A couple of locals are using the same design as their primary
antenna for 160 & 80 meters.

I got my "un-un" from Balun Designs, and they also have a chart on their
website with some suggested wire lengths.

Best of luck es 73 de

Dave - K9FN

On Tue, Jan 31, 2017 at 10:05 AM, Joe Subich, W4TV <[hidden email]> wrote:

>
> On 1/31/2017 3:43 AM, Thomas Horsten wrote:
>
>> Depends on your random wire and what band(s) you want to use. For
>> some bands the 9:1 "balun" (not used as a true balun in this case,
>> since both the coax and the random wire are unbalanced by nature)
>> will step the feedpoint impedance down to something that's a better
>> match for the 50 ohm coax, limiting coax losses.
>>
>
> Unless one is using a matching device designed as a current balun,
> the common 4:1 and 9:1 "baluns" are actually simple auto-transformers.
>
> The best approach is an auto-transformer at the feedpoint (with a
> counterpoise) followed by a true 1:1 current balun (common mode
> choke).
>
> The 9:1 "balun"/transformer may be more appropriate if the "wire"
> approaches a half wave on the frequencies of interest.  However,
> there is a definite interaction among antenna length, transformer
> ratio, feedline impedance and feedline length.
>
> 73,
>
>    ... Joe, W4TV
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun AND "random antennas"

Jim Brown-10
In reply to this post by NJ8M
All of this discussion becomes badly confusing by failing to describe
these circuit elements by their real name. The word "balun" is a bastard
-- it is widely used to describe nearly a dozen things that are VERY
different from each other.

W4TV got it right by adding the correct description, and this post
starts to get at it, but adds another bastard word, unun.

Two-windings that are coupled by a magnetic field are a TRANSFORMER.  If
the two windings have a terminal in common, they are an
AUTO-TRANSFORMER. A coil of coax is a common mode choke (and not a good
one). A section of transmission line wound around a ferrite core is a
COMMON MODE CHOKE, and if well designed (choice of ferrite material,
number of turns) can be a very good one.

Transformers and auto-transformers transform impedance by virtue of
their turns ratio. Arrays of common mode chokes can also be used to
match circuits of different impedances.

Last I looked, there was no description of the Elecraft "balun" telling
us what it is. Perhaps Eric or Wayne could add that to the catalog
listing for it.

Another point. SWR is NOT an indicator of how well an antenna works.
High SWR DOES increase loss in a feedline, but that matters only with
long feedlines and small diameter coax. That does NOT matter for typical
portable (or even mobile) operation, where feedlines are much too short
for loss to matter.

A high value of SWR as seen by a transmitter DOES limit that power that
the transmitter can put into the antenna. That's where the antenna tuner
comes in -- it transforms the impedance at the transmitter end of the
feedline (or the end of a wire plugged into the coax connector combined
with the counterpoise connected to the chassis) to the 50 ohm resistive
impedance that the transmitter wants to drive.

If we make RF current flow in a wire, it will radiate. How well it
radiates depends, of course, on its orientation. A wire laying on the
ground doesn't radiate very well. :)  A wire without a counterpoise will
use whatever it sees as a signal return. If that return happens to be
the earth, the earth, which is essentially a big resistor, will burn
much of the transmitter power. The "good" lengths of wire Wayne and
those spreadsheets list are simply lengths that are likely to present an
impedance within range of most antenna tuners for the bands that the
operator is likely to use.

73, Jim K9YC

On Tue,1/31/2017 7:31 AM, Morgan Bailey wrote:

> Be careful in the 9 to 1 vs 4 to 1 vs 1 to 1. The 9:1 is generally an UNUN.
> When you run 100 watts or less most 1kw manufactured baluns or Ununs will
> take a wide variety of SWR if you are only running 100 watts. Because this
> thread is I believe about QRP the amount of power dissipated due to loss is
> not a factor. When you jump to 500 watts, core heating, saturation and
> breakdown are a risk.
>
> For instance, the W2AU balun that is manufactured as a center feed point
> for a dipole is only rated for the power at 1:1 SWR. In the printed
> literature the power rating drops off considerable as one goes to 2:1. I
> have personal experience with this particular balun when an 80/40 trap
> dipole was constructed using that balun and the Unadalla KW40 traps.
> Operating 40 was no problem as it was nearly 1:1 anywhere we operated [CW],
> but on 80 CW the bandwidth was much narrower, as to be expected and nearing
> the edges when we ran 500 watts into the antenna with the balun rated at
> 1kw, well, it's core heated up, SWR drastically changed, heating the core
> windings so much that the solder to the SO239 connecting the core to the
> coax melted off. We knew that the SWR was between 2.5-3:1 on the edges of
> the 80 meter range. So be careful. Additionally, I have little faith in
> stick Baluns or Ununs, I personally do not believe they are nearly as good
> as a Toroid constructed balun.
>
> Ununs seem to in my experience, tolerate wide ranges in SWR. I have used a
> 9:1 unun and their new 52:1 transformer for end fed antennas  manufactured
> by Balundesigns.com with excellent results running 800 watts CW with little
> or no heating of the core and consistent results in a multiband
> environment. This was done using a 43, 53 and 87 foot end fed
> vertical/random wire/ inverted L and Half Square configurations. I have not
> modeled the pattern with NEC but I have compared it on Reverse Beacon
> Network [RBN] and I am definitely getting out. Full well knowing that Non
> resonant antennas are not as good as resonant ones, yes there is a
> difference in RBN reporting which favors the resonant, but, not always.
> This is because there is "funky lobe radiation"  that can give a high
> report to just random one or two reporting stations and then the rest are
> 10-15 db less than the resonant over a wider area of report stations. This
> supports the pattern is not predictable, or as predictable as a resonant
> antenna installed correctly. Knowing we are addressing compromise
> installation for multiband usage, this I believe is acceptable. If you have
> goals of working or covering with gain and directivity, then there is no
> replacement for well designed and well installed resonant antennas. This is
> especially true in the competitive environment of contesting.
>
> When an antenna that is not balanced is used, the RF will seek a way to
> ground. Problems with feed line radiation, and RF in the shack are
> problematic. Using a counterpoise or limited radial system is recommended
> to provide the missing balance and a path to ground. This is generally not
> a problem at QRP levels but because a few 100 miliwatts  of power coming
> back to the shack does not cause much problems but, jump that up to 10 or
> 100 watts and problems will surely make your life a living hell trying to
> keep the computer, keyboard, mouse cables connected and ATU from resetting
> and starting tuning cycle again and again. Best solution is to run resonant
> balanced antennas if one can, if one can't, invest in a few line isolators
> for the coax before it hits the shack and then have a good stock of Mix 31
> ferrite beads for each cable in the shack, eg, usb, keyer, mic, speaker,
> keyboard, mouse...you get the idea.
>
> In the end, when one runs QRP power, balun/unun saturation and performance
> degradation, allows most anything to fly, jump the power to 100 watts,
> watch out, then to 800 watts...reforming injection formed plastic is in
> your future. Although, relative to this discussion,  making an unun or
> balun with a T25 core and 32gauge wire will most likely produce the same
> disasterous results with 10 watts. LOL.
>
> Finally, Any antenna is better than No antenna.
>
> Morgan NJ8M
>
> On Tue, Jan 31, 2017 at 12:59 AM, gliderboy1955 via Elecraft <
> [hidden email]> wrote:
>
>> What are the advantages/disadvantages of using a 9:1 balun v. using the
>> switchable Elecraft balun at 1:1 or 4:1 or no balun at all when using a
>> random wire portable?
>> Why 9:1?
>> Thanks
>> 73 Eric WD6DBM
>>
>>
>> Sent on my Samsung Galaxy S® 6.
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]


______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

k6dgw
In reply to this post by Elecraft mailing list
 From the un-un/bal-un traffic, it seems there is some confusion and a
couple of "alternative facts" regarding this subject.  Fortunately, it
is much more straightforward that it might seem.

A bal-un is a transformer.  Technically, it has two windings on a
ferromagnetic core material which for RF is typically some flavor of
ferrite, usually in the form of a toroid.  Practically, the transformer
is often configured as an auto-transformer but it's still a
transformer.  In the classic case, a balanced load [e.g. center of a
half-wave wire] becomes unbalanced [coax, shield grounded] by the bal-un.

An un-un is exactly the same thing except both primary and secondary are
unbalanced [i.e. one side is grounded ... and often connected together].

Transformers [bal-un or un-un] transform one complex impedance into
another.  The transformation ratio is equal to the square of the turns
ratio between primary and secondary.  The little transformer that used
to go between the 300 ohm TV twin lead and the coax to the TV set had a
2:1 turns ratio, transforming 300 ohms to 75 ohms.  A 4:1 turns ratio
gives a 16:1 impedance transformation, 50 ohms becomes 750 ohms -- a 9:1
turns ratio gives an 81:1 impedance ratio and 50 ohms looks like 4
Kohms, roughly the practical impedance at the end of a half-wave wire.

So Eric, the terms "advantages" and "disadvantages" are somewhat
misleading.  The goal is to provide your transmitter with a load of
50+j0 ohms.  To work, the turns ratio of the bal-un must accomplish that
and that in turn depends on your frequency and length of your wire.  The
"advantage" of the Elecraft balun is that it is switchable so one device
can be used in multiple situations.

Note that the impedance at the feedpoint is complex.  It has both
resistive and reactive [inductive/capacitive] components.  Only at a
resonant frequency will the reactance be zero.  The bal-un/un-un
transforms both components by the square of the turns ratio.  It doesn't
eliminate the reactance.

So-called "current baluns" are really chokes that present a very high
impedance to the current that might be flowing on the outside surface of
the coax shield [common mode current].  They do not affect the equal and
opposite currents flowing on the center conductor and inside surface of
the shield.

A dipole is anything that has two "poles."  A length of wire has two
ends [poles].  It doesn't matter how long it is.  As Ron has pointed out
before, the classic ham usage of "dipole" is a half-wavelength wire fed
in the center, but technically, length is irrelevant.  A water molecule
is an electrical dipole built like a dumbell, one end is positive, the
other negative.  The field in the microwave makes them spin and their
friction heats up your coffee.

Hope this helps.

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 1/30/2017 10:59 PM, gliderboy1955 via Elecraft wrote:
> What are the advantages/disadvantages of using a 9:1 balun v. using the switchable Elecraft balun at 1:1 or 4:1 or no balun at all when using a random wire portable?
> Why 9:1?
> Thanks
> 73 Eric WD6DBM
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun AND "random antennas"

Joe Subich, W4TV-4
In reply to this post by Jim Brown-10

On 1/31/2017 1:50 PM, Jim Brown wrote:
> Last I looked, there was no description of the Elecraft "balun" telling
> us what it is. Perhaps Eric or Wayne could add that to the catalog
> listing for it.

The manual for the Elecraft BL2 shows exactly what it is:
     http://www.elecraft.com/manual/BL2_Balun_Rev_B.pdf

Takes exactly 30 seconds to look at the schematic to see that the BL2
is a Rutheroff balun - two common mode chokes with the input in
parallel and the output switchable between parallel (1:1) and series
(4:1).  Each pair of windings is roughly 100 Ohm line so the impedance
through the balun is a fairly good approximation of the desired value
in a 50 Ohm system.

73,

    ... Joe, W4TV
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

Joe Subich, W4TV-4
In reply to this post by k6dgw

On 1/31/2017 2:16 PM, Fred Jensen wrote:
 > A bal-un is a transformer.  Technically, it has two windings on a
 > ferromagnetic core material which for RF is typically some flavor of
 > ferrite, usually in the form of a toroid.

Most common baluns are *not transformers* as the energy does not pass
solely from input to output by magnetic coupling.  In fact, I would
hazard a guess that *none* of the devices advertised/sold as baluns
are transformers.  Yes, many of the inexpensive 4:1 "baluns" - the
voltage type (auto-transformer) baluns - may qualify due to the
magnetic coupling between windings but they are *not* baluns in that
they do not provide a balanced to unbalanced transformation (they are,
in your terms an "un-un").

> In the classic case, a balanced load [e.g. center of a half-wave
> wire] becomes unbalanced [coax, shield grounded] by the bal-un.

Again, NO!  The balanced load is not "unbalanced" by the balun.  A
properly designed balun *keeps the system balanced* by preventing
current from flowing on the "third wire" (the *outside* of the coax)
which would otherwise "unbalance" the system.

Due to skin effect, a properly terminated coaxial cable is a three
wire transmission line.  The center conductor and *inside* of the
shield form one circuit (which is "balanced" due to the laws of
physics) and the *outside* of the shield carries "unbalanced" (or
common mode) current due to any difference in potential between
the ends of the cable or induced currents from external fields.

73,

    ... Joe, W4TV


______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

Matt Zilmer-3
Excellent explanation, Joe.

Thanks,

matt W6NIA


On 1/31/2017 12:12 PM, Joe Subich, W4TV wrote:

>
> On 1/31/2017 2:16 PM, Fred Jensen wrote:
> > A bal-un is a transformer.  Technically, it has two windings on a
> > ferromagnetic core material which for RF is typically some flavor of
> > ferrite, usually in the form of a toroid.
>
> Most common baluns are *not transformers* as the energy does not pass
> solely from input to output by magnetic coupling.  In fact, I would
> hazard a guess that *none* of the devices advertised/sold as baluns
> are transformers.  Yes, many of the inexpensive 4:1 "baluns" - the
> voltage type (auto-transformer) baluns - may qualify due to the
> magnetic coupling between windings but they are *not* baluns in that
> they do not provide a balanced to unbalanced transformation (they are,
> in your terms an "un-un").
>
>> In the classic case, a balanced load [e.g. center of a half-wave
>> wire] becomes unbalanced [coax, shield grounded] by the bal-un.
>
> Again, NO!  The balanced load is not "unbalanced" by the balun.  A
> properly designed balun *keeps the system balanced* by preventing
> current from flowing on the "third wire" (the *outside* of the coax)
> which would otherwise "unbalance" the system.
>
> Due to skin effect, a properly terminated coaxial cable is a three
> wire transmission line.  The center conductor and *inside* of the
> shield form one circuit (which is "balanced" due to the laws of
> physics) and the *outside* of the shield carries "unbalanced" (or
> common mode) current due to any difference in potential between
> the ends of the cable or induced currents from external fields.
>
> 73,
>
>    ... Joe, W4TV
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

--
Always store beer in a dark place.  - R. Heinlein

Matt Zilmer, W6NIA
[Shiraz]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

Don Wilhelm
In reply to this post by k6dgw
What I have failed to see in this thread is that the *wire* in a proper
"balun" (more properly a common mode choke) is a transmission line,

That transmission line can be two conductors side by side, or it can be
two twisted wires, or it can be coax or any other type of transmission line.

Its job is to block RF Current from flowing on the outside of the coax
shield.  It is not a transformer, but a choking impedance.

73,
Don W3FPR

On 1/31/2017 2:16 PM, Fred Jensen wrote:
>
> A bal-un is a transformer.  Technically, it has two windings on a
> ferromagnetic core material which for RF is typically some flavor of
> ferrite, usually in the form of a toroid.
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

Bill K9YEQ
In reply to this post by NJ8M
Morgan,

I looked for the 52:1 transformer at Balundesigns.com.  No such animal found unless I am not looking in the right place.

73,
Bill
K9YEQ

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Morgan Bailey
Sent: Tuesday, January 31, 2017 9:31 AM
To: gliderboy1955 <[hidden email]>; [hidden email]
Subject: Re: [Elecraft] 9:1 Balun

Be careful in the 9 to 1 vs 4 to 1 vs 1 to 1. The 9:1 is generally an UNUN.
When you run 100 watts or less most 1kw manufactured baluns or Ununs will take a wide variety of SWR if you are only running 100 watts. Because this thread is I believe about QRP the amount of power dissipated due to loss is not a factor. When you jump to 500 watts, core heating, saturation and breakdown are a risk.

For instance, the W2AU balun that is manufactured as a center feed point for a dipole is only rated for the power at 1:1 SWR. In the printed literature the power rating drops off considerable as one goes to 2:1. I have personal experience with this particular balun when an 80/40 trap dipole was constructed using that balun and the Unadalla KW40 traps.
Operating 40 was no problem as it was nearly 1:1 anywhere we operated [CW], but on 80 CW the bandwidth was much narrower, as to be expected and nearing the edges when we ran 500 watts into the antenna with the balun rated at 1kw, well, it's core heated up, SWR drastically changed, heating the core windings so much that the solder to the SO239 connecting the core to the coax melted off. We knew that the SWR was between 2.5-3:1 on the edges of the 80 meter range. So be careful. Additionally, I have little faith in stick Baluns or Ununs, I personally do not believe they are nearly as good as a Toroid constructed balun.

Ununs seem to in my experience, tolerate wide ranges in SWR. I have used a
9:1 unun and their new 52:1 transformer for end fed antennas  manufactured by Balundesigns.com with excellent results running 800 watts CW with little or no heating of the core and consistent results in a multiband environment. This was done using a 43, 53 and 87 foot end fed vertical/random wire/ inverted L and Half Square configurations. I have not modeled the pattern with NEC but I have compared it on Reverse Beacon Network [RBN] and I am definitely getting out. Full well knowing that Non resonant antennas are not as good as resonant ones, yes there is a difference in RBN reporting which favors the resonant, but, not always.
This is because there is "funky lobe radiation"  that can give a high report to just random one or two reporting stations and then the rest are
10-15 db less than the resonant over a wider area of report stations. This supports the pattern is not predictable, or as predictable as a resonant antenna installed correctly. Knowing we are addressing compromise installation for multiband usage, this I believe is acceptable. If you have goals of working or covering with gain and directivity, then there is no replacement for well designed and well installed resonant antennas. This is especially true in the competitive environment of contesting.

When an antenna that is not balanced is used, the RF will seek a way to ground. Problems with feed line radiation, and RF in the shack are problematic. Using a counterpoise or limited radial system is recommended to provide the missing balance and a path to ground. This is generally not a problem at QRP levels but because a few 100 miliwatts  of power coming back to the shack does not cause much problems but, jump that up to 10 or
100 watts and problems will surely make your life a living hell trying to keep the computer, keyboard, mouse cables connected and ATU from resetting and starting tuning cycle again and again. Best solution is to run resonant balanced antennas if one can, if one can't, invest in a few line isolators for the coax before it hits the shack and then have a good stock of Mix 31 ferrite beads for each cable in the shack, eg, usb, keyer, mic, speaker, keyboard, mouse...you get the idea.

In the end, when one runs QRP power, balun/unun saturation and performance degradation, allows most anything to fly, jump the power to 100 watts, watch out, then to 800 watts...reforming injection formed plastic is in your future. Although, relative to this discussion,  making an unun or balun with a T25 core and 32gauge wire will most likely produce the same disasterous results with 10 watts. LOL.

Finally, Any antenna is better than No antenna.

Morgan NJ8M

On Tue, Jan 31, 2017 at 12:59 AM, gliderboy1955 via Elecraft < [hidden email]> wrote:

> What are the advantages/disadvantages of using a 9:1 balun v. using
> the switchable Elecraft balun at 1:1 or 4:1 or no balun at all when
> using a random wire portable?
> Why 9:1?
> Thanks
> 73 Eric WD6DBM
>
>
> Sent on my Samsung Galaxy S® 6.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net Please help support this email
> list: http://www.qsl.net/donate.html Message delivered to
> [hidden email]
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email]
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

k6dgw
In reply to this post by Joe Subich, W4TV-4
This list is a lot like being male and married ... no matter what you do
or say, you're going to be told you're wrong. [:-)

> Most common baluns are *not transformers* as the energy does not pass
> solely from input to output by magnetic coupling.  In fact, I would
> hazard a guess that *none* of the devices advertised/sold as baluns
> are transformers.  Yes, many of the inexpensive 4:1 "baluns" - the
> voltage type (auto-transformer) baluns - may qualify due to the
> magnetic coupling between windings but they are *not* baluns in that
> they do not provide a balanced to unbalanced transformation (they are,
> in your terms an "un-un").
We were at our previous QTH on 5 acres for 38 years and I had a lot of
time and space to experiment with antennas.  I had or had used 6
different baluns.  All were transformers.  I currently have one on my
HOA-Stealth wire.  It too is a transformer.  I also have an unused one
in the garage that is an autotransformer with the shield carried through
to one of the terminals on the "other" side.  It is an Un-Un, but it has
a 4:1 turns ratio [16:1 impedance transformation] as well.

While transformers are not the only way to build a bal-un or un-un,
that's 7 bal-uns and 1 un-un, all transformers.

One can build a balun from transmission line since a transmission line
will act as a transformer.  They're frequency dependent of course, and
typically used at VHF and up.

Incidentally, one of the transformer baluns with an SO-239 connector
carried a rating of "10 KW, 11 KV."  I don't think I'd want to stuff
10KW into that connector. [:-)  I still have it, I'll never use it
again, I'll give it away if anyone wants it.
>
>> In the classic case, a balanced load [e.g. center of a half-wave
>> wire] becomes unbalanced [coax, shield grounded] by the bal-un.
>
Again, NO!  The balanced load is not "unbalanced" by the balun.

Did not intend to say that, English can be seriously difficult when
describing something.  Let's see if I can re-word that to better convey
the meaning ...

"The balanced side of the balun is balanced, and it stays that way.  
That's half the point of all this drivel [the other half is impedance
transformation].  They sometimes use standoff's or such for the balanced
connection.  Once you go through the balun toward the transmitter, you
get an unbalanced connection for the unbalanced coax, usually an
SO-239.  The balun thus allows a balanced load [e.g. the center of a
wire] to remain balanced when fed with an unbalanced transmission line."
That should help.

> Due to skin effect, a properly terminated coaxial cable is a three
> wire transmission line.  The center conductor and *inside* of the
> shield form one circuit (which is "balanced" due to the laws of
> physics) and the *outside* of the shield carries "unbalanced" (or
> common mode) current due to any difference in potential between
> the ends of the cable or induced currents from external fields.

Yep, that fact has been discussed multiple times here.

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

kevinr@coho.net
We have all learned to say, "Yes Dear." and carry on.

     73,

         Kevin.  KD5ONS


On 1/31/2017 3:11 PM, Fred Jensen wrote:

> This list is a lot like being male and married ... no matter what you
> do or say, you're going to be told you're wrong. [:-)
>
>> Most common baluns are *not transformers* as the energy does not pass
>> solely from input to output by magnetic coupling.  In fact, I would
>> hazard a guess that *none* of the devices advertised/sold as baluns
>> are transformers.  Yes, many of the inexpensive 4:1 "baluns" - the
>> voltage type (auto-transformer) baluns - may qualify due to the
>> magnetic coupling between windings but they are *not* baluns in that
>> they do not provide a balanced to unbalanced transformation (they are,
>> in your terms an "un-un").
> We were at our previous QTH on 5 acres for 38 years and I had a lot of
> time and space to experiment with antennas.  I had or had used 6
> different baluns.  All were transformers.  I currently have one on my
> HOA-Stealth wire.  It too is a transformer.  I also have an unused one
> in the garage that is an autotransformer with the shield carried
> through to one of the terminals on the "other" side.  It is an Un-Un,
> but it has a 4:1 turns ratio [16:1 impedance transformation] as well.
>
> While transformers are not the only way to build a bal-un or un-un,
> that's 7 bal-uns and 1 un-un, all transformers.
>
> One can build a balun from transmission line since a transmission line
> will act as a transformer.  They're frequency dependent of course, and
> typically used at VHF and up.
>
> Incidentally, one of the transformer baluns with an SO-239 connector
> carried a rating of "10 KW, 11 KV."  I don't think I'd want to stuff
> 10KW into that connector. [:-)  I still have it, I'll never use it
> again, I'll give it away if anyone wants it.
>>
>>> In the classic case, a balanced load [e.g. center of a half-wave
>>> wire] becomes unbalanced [coax, shield grounded] by the bal-un.
>>
> Again, NO!  The balanced load is not "unbalanced" by the balun.
>
> Did not intend to say that, English can be seriously difficult when
> describing something.  Let's see if I can re-word that to better
> convey the meaning ...
>
> "The balanced side of the balun is balanced, and it stays that way.  
> That's half the point of all this drivel [the other half is impedance
> transformation].  They sometimes use standoff's or such for the
> balanced connection.  Once you go through the balun toward the
> transmitter, you get an unbalanced connection for the unbalanced coax,
> usually an SO-239.  The balun thus allows a balanced load [e.g. the
> center of a wire] to remain balanced when fed with an unbalanced
> transmission line." That should help.
>
>> Due to skin effect, a properly terminated coaxial cable is a three
>> wire transmission line.  The center conductor and *inside* of the
>> shield form one circuit (which is "balanced" due to the laws of
>> physics) and the *outside* of the shield carries "unbalanced" (or
>> common mode) current due to any difference in potential between
>> the ends of the cable or induced currents from external fields.
>
> Yep, that fact has been discussed multiple times here.
>
> 73,
>
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

Thomas Horsten
There's quite a lot of interesting theory in the thread, but I think for
practical purposes my original answer still covers it, under the premise
we're talking QRP with a short feedline of RG58 (a few yards).

Small autotransformer baluns like the LDG 4:1 I use (I haven't tried the
Elecraft one but I assume it's similar), are just really practical because
they have screw terminals for the LW and the counterpoise. It's pretty easy
to build your own if you really want to, but what happens inside that box
is not likely to have a huge effect on the QSO's you manage. For portable
ops, rearranging the long wire/counterpoise a bit is likely to improve your
signal more than switching from a 4:1 balun to a 9:1, or none at all.

73, Thomas OZ5TN (aka M0TRN, AF7BE)

On 1 February 2017 at 01:02, [hidden email] <[hidden email]> wrote:

> We have all learned to say, "Yes Dear." and carry on.
>
>     73,
>
>         Kevin.  KD5ONS
>
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

Lynn W. Taylor, WB6UUT
In reply to this post by Elecraft mailing list
According to the KX3 documentation, the KXAT3 will handle a 10:1 VSWR
and "match" it.

If I did the math right (always a question) your load must be between
about 5 ohms and 500 ohms, so if your antenna is about 400 ohms (not
resistance, but impedance) then you're okay.

If you have a 600 ohm antenna, the tuner won't be able to give the
finals in the transmitter a perfect 50 ohms.

Use a 4:1 Balun, and your 600 ohm load would be transformed (a balun is
a transformer) 150 ohms and the tuner would handle it just fine.

Use a 9:1 Balun and your 600 ohm load would be transformed to about 66 ohms.

That doesn't say the antenna would radiate it, but the transmitter could
make power and the tuner/transmission line would deliver it to the radiator.

73 -- Lynn

On 1/30/2017 10:59 PM, gliderboy1955 via Elecraft wrote:
> What are the advantages/disadvantages of using a 9:1 balun v. using the switchable Elecraft balun at 1:1 or 4:1 or no balun at all when using a random wire portable?
> Why 9:1?
> Thanks
> 73 Eric WD6DBM
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

K9MA
On 1/31/2017 19:03, Lynn W. Taylor, WB6UUT wrote:
> If I did the math right (always a question) your load must be between
> about 5 ohms and 500 ohms, so if your antenna is about 400 ohms (not
> resistance, but impedance) then you're okay.
Not necessarily.  That 400 Ohms could be almost pure reactance, like
1+j399.999, an almost infinite SWR.  That's why ATU specs call out the
SWR range.  Even then, that might be for mostly resistive loads, as it's
really hard to specify the whole range of impedances an ATU can match.

73,

Scott  K9MA

--
Scott  K9MA

[hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

Lynn W. Taylor, WB6UUT
That's the problem with oversimplifying an explanation.

I read the original as "is it best practice to always use a 9:1 balun"
and the answer of course is, "if you don't need a 9:1 impedance
transformation, then you don't need a 9:1 balun."

73 -- Lynn

On 1/31/2017 5:17 PM, K9MA wrote:

> On 1/31/2017 19:03, Lynn W. Taylor, WB6UUT wrote:
>> If I did the math right (always a question) your load must be between
>> about 5 ohms and 500 ohms, so if your antenna is about 400 ohms (not
>> resistance, but impedance) then you're okay.
> Not necessarily.  That 400 Ohms could be almost pure reactance, like
> 1+j399.999, an almost infinite SWR.  That's why ATU specs call out the
> SWR range.  Even then, that might be for mostly resistive loads, as
> it's really hard to specify the whole range of impedances an ATU can
> match.
>
> 73,
>
> Scott  K9MA
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

Kevin - K4VD
In reply to this post by Lynn W. Taylor, WB6UUT
On Tue, Jan 31, 2017 at 8:03 PM, Lynn W. Taylor, WB6UUT <
[hidden email]> wrote:

>
> That doesn't say the antenna would radiate it, but the transmitter could
> make power and the tuner/transmission line would deliver it to the radiat


​Why wouldn't the antenna radiate it? Seems to me if you can deliver power
then what's not being radiated as heat would be radiated as RF. I have
weird ideas about how all this works.

One thing I think would be great to have, especially built in as part of an
antenna tuner, is a switchable BALUN. When someone needs to throw up random
antennas it would be handy to be able to just switch in the appropriate
ratio. Can a BALUN be tapped maybe? It seems it would extend the range of
internally antenna tuners also. I should know this stuff. But I don't.

73,
Kev K4VD
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
Reply | Threaded
Open this post in threaded view
|

Re: 9:1 Balun

Thomas Horsten
Many manual ATU's consist of a variable capacitor and a tapped inductor.
It's a matching network but also works as an "on-the-fly" switchable balun.
The difference is the location. The ATU typically sits at the rig end where
a balun sits at the antenna feedpoint (and so may present the coax with a
better matching impedance, plus acts as a choke reducing common mode
current). You can have a remote-controlled automatic ATU at the feed point
in which case you'll always have a perfect match for your coax. Great for a
stealth multiband in the attic, but it's an expensive and clunky solution
for portable operations.

73 Thomas OZ5TN (aka M0TRN, AF7BE)

On 1 February 2017 at 02:35, Kevin - K4VD <[hidden email]> wrote:

> One thing I think would be great to have, especially built in as part of an
> antenna tuner, is a switchable BALUN. When someone needs to throw up random
> antennas it would be handy to be able to just switch in the appropriate
> ratio. Can a BALUN be tapped maybe? It seems it would extend the range of
> internally antenna tuners also. I should know this stuff. But I don't.
>
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
12