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Old July 24th 05, 07:32 PM
greg knapp 5
 
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Default Balanced vs. Unbalanced Tuner

I have decided to erect an 80 meter dipole at 70 feet fed with 450 or 600
ohm open wire, for use on ALL HF bands between 80 and 10 meters. Power
output will be 1000W CW and 1200W PEP.
(1) Which is the better setup and why: a Ten Tec 238B unbalanced tuner with
a DX Engineering 1:1 balun on antenna side of tuner OR a Palstar BT1500BAL
balanced tuner?
(2) Also, if I later decide to erect an inverted L for 160/80, can I use a
balanced tuner with a DX Engineering 1:1 balun put on antenna side of tuner,
but reversed in direction (converting unbalanced to balanced), or need I get
a different tuner?
(3) In a perfect world, I'd buy both tuners (one for balanced and one for
unbalanced), but I can't afford it. Also, if I go with the unbalanced tuner,
will the balun waste a ton of RF in heat and loss?
(4) I made a similar post on the Ten Tec List, and received lots of advice
on point designs, but not the COMPARISON data I was looking for that will
help me make the final decision to go with a balanced tuner vs an unbalanced
(with balun) tuner.
(5) I have plenty of room, would it make any difference if I put a 160 meter
dipole instead?
Thanks & 73,
Greg, N6GK


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Old July 24th 05, 07:39 PM
Fred W4JLE
 
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Default

I use similar antennas, the ladder line is tied directly to coax with
ferrite beads over the coax to act as a choke balun.

When I used a tuner, I simply used the unbalanced input.

If your intention is to take the ladder line all the way to the tuner, go
with a balanced tuner.

"greg knapp 5" wrote in message
...
I have decided to erect an 80 meter dipole at 70 feet fed with 450 or 600
ohm open wire, for use on ALL HF bands between 80 and 10 meters. Power
output will be 1000W CW and 1200W PEP.
(1) Which is the better setup and why: a Ten Tec 238B unbalanced tuner

with
a DX Engineering 1:1 balun on antenna side of tuner OR a Palstar BT1500BAL
balanced tuner?
(2) Also, if I later decide to erect an inverted L for 160/80, can I use a
balanced tuner with a DX Engineering 1:1 balun put on antenna side of

tuner,
but reversed in direction (converting unbalanced to balanced), or need I

get
a different tuner?
(3) In a perfect world, I'd buy both tuners (one for balanced and one for
unbalanced), but I can't afford it. Also, if I go with the unbalanced

tuner,
will the balun waste a ton of RF in heat and loss?
(4) I made a similar post on the Ten Tec List, and received lots of advice
on point designs, but not the COMPARISON data I was looking for that will
help me make the final decision to go with a balanced tuner vs an

unbalanced
(with balun) tuner.
(5) I have plenty of room, would it make any difference if I put a 160

meter
dipole instead?
Thanks & 73,
Greg, N6GK




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Old July 24th 05, 07:48 PM
Dave
 
Posts: n/a
Default

how does the balanced tuner get from the unbalanced output of the amplifier
and the balanced feedline? is there not a balun in there somewhere anyway?

"greg knapp 5" wrote in message
...
I have decided to erect an 80 meter dipole at 70 feet fed with 450 or 600
ohm open wire, for use on ALL HF bands between 80 and 10 meters. Power
output will be 1000W CW and 1200W PEP.
(1) Which is the better setup and why: a Ten Tec 238B unbalanced tuner
with a DX Engineering 1:1 balun on antenna side of tuner OR a Palstar
BT1500BAL balanced tuner?
(2) Also, if I later decide to erect an inverted L for 160/80, can I use a
balanced tuner with a DX Engineering 1:1 balun put on antenna side of
tuner, but reversed in direction (converting unbalanced to balanced), or
need I get a different tuner?
(3) In a perfect world, I'd buy both tuners (one for balanced and one for
unbalanced), but I can't afford it. Also, if I go with the unbalanced
tuner, will the balun waste a ton of RF in heat and loss?
(4) I made a similar post on the Ten Tec List, and received lots of advice
on point designs, but not the COMPARISON data I was looking for that will
help me make the final decision to go with a balanced tuner vs an
unbalanced (with balun) tuner.
(5) I have plenty of room, would it make any difference if I put a 160
meter dipole instead?
Thanks & 73,
Greg, N6GK



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Old July 24th 05, 08:22 PM
Dave Platt
 
Posts: n/a
Default

In article ,
Dave wrote:

how does the balanced tuner get from the unbalanced output of the amplifier
and the balanced feedline? is there not a balun in there somewhere anyway?


I've seen three approaches used:

- Asymmetrical (unbalanced) tuner of the T or L or pi configuration,
with a balun at the output. This seems to be the most common
configuration, but is often said to suffer from a degraded balance
or unacceptable losses in the balun when feeding high-Z loads.
It's not easy for a balun to provide adequate choking reactance
when feeding such loads.

- Tuners which use a symmetrical T or L configuration, with the input
to the matching network being fed from the rig/amplifier's 50-ohm
output via a balun. An internal W2DU-type "ferrite beads on coax"
balun seems to be popular in such designs.

- Link-coupled tuners, such as the Johnson Matchbox and the newer
Z-match designs. The input side of the circuit operates unbalanced
and is usually asymmetrical, while the output side (the link) is
balanced with respect to ground. The input and output sides are
coupled inductively. There's sometimes a small amount of imbalance
created by capacitive coupling across the link, but this seems to
be small enough to have little practical effect on the quality of
the balance. In this case, the balanced-to-unbalanced function is
performed by the inductive link, and there's no separate "balun"
component.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!
  #5   Report Post  
Old July 24th 05, 10:27 PM
Dave
 
Posts: n/a
Default


"Dave Platt" wrote in message
...
In article ,
Dave wrote:

how does the balanced tuner get from the unbalanced output of the
amplifier
and the balanced feedline? is there not a balun in there somewhere
anyway?


I've seen three approaches used:

- Asymmetrical (unbalanced) tuner of the T or L or pi configuration,
with a balun at the output. This seems to be the most common
configuration, but is often said to suffer from a degraded balance
or unacceptable losses in the balun when feeding high-Z loads.
It's not easy for a balun to provide adequate choking reactance
when feeding such loads.

- Tuners which use a symmetrical T or L configuration, with the input
to the matching network being fed from the rig/amplifier's 50-ohm
output via a balun. An internal W2DU-type "ferrite beads on coax"
balun seems to be popular in such designs.

- Link-coupled tuners, such as the Johnson Matchbox and the newer
Z-match designs. The input side of the circuit operates unbalanced
and is usually asymmetrical, while the output side (the link) is
balanced with respect to ground. The input and output sides are
coupled inductively. There's sometimes a small amount of imbalance
created by capacitive coupling across the link, but this seems to
be small enough to have little practical effect on the quality of
the balance. In this case, the balanced-to-unbalanced function is
performed by the inductive link, and there's no separate "balun"
component.

so, no matter how you spell it, unbalanced in, balanced out, somehow the
tuner either has a component called specifically a balun, or combines it
into other parts that also transform impedance... essentially making the
whole tuner one big balun. no matter how its done somewhere between the
amplifier unbalanced output and the balanced wire there is something doing
the balun function.




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Old July 25th 05, 02:22 AM
greg knapp 5
 
Posts: n/a
Default

I think you summarized it well. thanks!

"Dave" wrote in message
...

"Dave Platt" wrote in message
...
In article ,
Dave wrote:

how does the balanced tuner get from the unbalanced output of the
amplifier
and the balanced feedline? is there not a balun in there somewhere
anyway?


I've seen three approaches used:

- Asymmetrical (unbalanced) tuner of the T or L or pi configuration,
with a balun at the output. This seems to be the most common
configuration, but is often said to suffer from a degraded balance
or unacceptable losses in the balun when feeding high-Z loads.
It's not easy for a balun to provide adequate choking reactance
when feeding such loads.

- Tuners which use a symmetrical T or L configuration, with the input
to the matching network being fed from the rig/amplifier's 50-ohm
output via a balun. An internal W2DU-type "ferrite beads on coax"
balun seems to be popular in such designs.

- Link-coupled tuners, such as the Johnson Matchbox and the newer
Z-match designs. The input side of the circuit operates unbalanced
and is usually asymmetrical, while the output side (the link) is
balanced with respect to ground. The input and output sides are
coupled inductively. There's sometimes a small amount of imbalance
created by capacitive coupling across the link, but this seems to
be small enough to have little practical effect on the quality of
the balance. In this case, the balanced-to-unbalanced function is
performed by the inductive link, and there's no separate "balun"
component.

so, no matter how you spell it, unbalanced in, balanced out, somehow the
tuner either has a component called specifically a balun, or combines it
into other parts that also transform impedance... essentially making the
whole tuner one big balun. no matter how its done somewhere between the
amplifier unbalanced output and the balanced wire there is something doing
the balun function.




  #7   Report Post  
Old July 24th 05, 08:36 PM
Ham op
 
Posts: n/a
Default

No balun required in a properly designed unbalanced tuner. See the
Johnson Matchbox series.

Dave wrote:

how does the balanced tuner get from the unbalanced output of the amplifier
and the balanced feedline? is there not a balun in there somewhere anyway?

"greg knapp 5" wrote in message
...

I have decided to erect an 80 meter dipole at 70 feet fed with 450 or 600
ohm open wire, for use on ALL HF bands between 80 and 10 meters. Power
output will be 1000W CW and 1200W PEP.
(1) Which is the better setup and why: a Ten Tec 238B unbalanced tuner
with a DX Engineering 1:1 balun on antenna side of tuner OR a Palstar
BT1500BAL balanced tuner?
(2) Also, if I later decide to erect an inverted L for 160/80, can I use a
balanced tuner with a DX Engineering 1:1 balun put on antenna side of
tuner, but reversed in direction (converting unbalanced to balanced), or
need I get a different tuner?
(3) In a perfect world, I'd buy both tuners (one for balanced and one for
unbalanced), but I can't afford it. Also, if I go with the unbalanced
tuner, will the balun waste a ton of RF in heat and loss?
(4) I made a similar post on the Ten Tec List, and received lots of advice
on point designs, but not the COMPARISON data I was looking for that will
help me make the final decision to go with a balanced tuner vs an
unbalanced (with balun) tuner.
(5) I have plenty of room, would it make any difference if I put a 160
meter dipole instead?
Thanks & 73,
Greg, N6GK





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Old July 24th 05, 11:21 PM
 
Posts: n/a
Default



Ham op wrote:
No balun required in a properly designed unbalanced tuner. See the
Johnson Matchbox series.

Dave wrote:

how does the balanced tuner get from the unbalanced output of the amplifier
and the balanced feedline? is there not a balun in there somewhere anyway?

"greg knapp 5" wrote in message
...

I have decided to erect an 80 meter dipole at 70 feet fed with 450 or 600
ohm open wire, for use on ALL HF bands between 80 and 10 meters. Power
output will be 1000W CW and 1200W PEP.
(1) Which is the better setup and why: a Ten Tec 238B unbalanced tuner
with a DX Engineering 1:1 balun on antenna side of tuner OR a Palstar
BT1500BAL balanced tuner?
(2) Also, if I later decide to erect an inverted L for 160/80, can I use a
balanced tuner with a DX Engineering 1:1 balun put on antenna side of
tuner, but reversed in direction (converting unbalanced to balanced), or
need I get a different tuner?
(3) In a perfect world, I'd buy both tuners (one for balanced and one for
unbalanced), but I can't afford it. Also, if I go with the unbalanced
tuner, will the balun waste a ton of RF in heat and loss?
(4) I made a similar post on the Ten Tec List, and received lots of advice
on point designs, but not the COMPARISON data I was looking for that will
help me make the final decision to go with a balanced tuner vs an
unbalanced (with balun) tuner.
(5) I have plenty of room, would it make any difference if I put a 160
meter dipole instead?
Thanks & 73,
Greg, N6GK

Hi Ham Op, did you mean no balun required in a properly designed
"balanced tuner"? Are not the Johnson Series balanced tuners?
Gary N4AST

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Old July 25th 05, 01:11 AM
Ham op
 
Posts: n/a
Default

The Johnson Matchbox series are BALANCED tuners. I see my comment was
ambiguous.

wrote:


Ham op wrote:

No balun required in a properly designed unbalanced tuner. See the
Johnson Matchbox series.

Dave wrote:


how does the balanced tuner get from the unbalanced output of the amplifier
and the balanced feedline? is there not a balun in there somewhere anyway?

"greg knapp 5" wrote in message
...


I have decided to erect an 80 meter dipole at 70 feet fed with 450 or 600
ohm open wire, for use on ALL HF bands between 80 and 10 meters. Power
output will be 1000W CW and 1200W PEP.
(1) Which is the better setup and why: a Ten Tec 238B unbalanced tuner
with a DX Engineering 1:1 balun on antenna side of tuner OR a Palstar
BT1500BAL balanced tuner?
(2) Also, if I later decide to erect an inverted L for 160/80, can I use a
balanced tuner with a DX Engineering 1:1 balun put on antenna side of
tuner, but reversed in direction (converting unbalanced to balanced), or
need I get a different tuner?
(3) In a perfect world, I'd buy both tuners (one for balanced and one for
unbalanced), but I can't afford it. Also, if I go with the unbalanced
tuner, will the balun waste a ton of RF in heat and loss?
(4) I made a similar post on the Ten Tec List, and received lots of advice
on point designs, but not the COMPARISON data I was looking for that will
help me make the final decision to go with a balanced tuner vs an
unbalanced (with balun) tuner.
(5) I have plenty of room, would it make any difference if I put a 160
meter dipole instead?
Thanks & 73,
Greg, N6GK


Hi Ham Op, did you mean no balun required in a properly designed
"balanced tuner"? Are not the Johnson Series balanced tuners?
Gary N4AST


  #10   Report Post  
Old July 25th 05, 06:23 PM
Butch Magee
 
Posts: n/a
Default

Large Toroid mounted on the inside back wall of the tuner.





Dave wrote:
how does the balanced tuner get from the unbalanced output of the amplifier
and the balanced feedline? is there not a balun in there somewhere anyway?

"greg knapp 5" wrote in message
...

I have decided to erect an 80 meter dipole at 70 feet fed with 450 or 600
ohm open wire, for use on ALL HF bands between 80 and 10 meters. Power
output will be 1000W CW and 1200W PEP.
(1) Which is the better setup and why: a Ten Tec 238B unbalanced tuner
with a DX Engineering 1:1 balun on antenna side of tuner OR a Palstar
BT1500BAL balanced tuner?
(2) Also, if I later decide to erect an inverted L for 160/80, can I use a
balanced tuner with a DX Engineering 1:1 balun put on antenna side of
tuner, but reversed in direction (converting unbalanced to balanced), or
need I get a different tuner?
(3) In a perfect world, I'd buy both tuners (one for balanced and one for
unbalanced), but I can't afford it. Also, if I go with the unbalanced
tuner, will the balun waste a ton of RF in heat and loss?
(4) I made a similar post on the Ten Tec List, and received lots of advice
on point designs, but not the COMPARISON data I was looking for that will
help me make the final decision to go with a balanced tuner vs an
unbalanced (with balun) tuner.
(5) I have plenty of room, would it make any difference if I put a 160
meter dipole instead?
Thanks & 73,
Greg, N6GK






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