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

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

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

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!

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

Google search for "balanced-balanced " or "Richard Measures" (author of
article).
I built one, it worked great.

On Sun, 24 Jul 2005 11:32:37 -0700, "greg knapp 5"
wrote:

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


Have not seen any published tests comparing balanced vs. unbalanced
tuners, so any comparisons will probably be theoretical in nature.
Also, instread of the dx engineering balun, you might look at a
w2du-style balun -- see his article at
http://www.w2du.com/Reflection2.html

bob
k5qwg

"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.

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

On Sun, 24 Jul 2005 11:32:37 -0700, "greg knapp 5"
wrote:

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.

Is the radiation pattern on all of these bands acceptable/useful?

(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?

Study this before deciding: http://eznec.com/misc/ibalun.txt

Considering the capacitor in the Palstar isn't a balanced design, the
capacitive coupling from it to ground is asymetrical, so I would not
call it a balanced tuner. Also, I don't see anything that looks like
a 1500 W balun in there.

Ten Tec says, "Because there are only two variable components, there
is only one setting of each which will provide a perfect match to a
given load impedance. This unique setting automatically provides the
lowest Q network possible. Low Q means low circulating currents, hence
low loss, and it also provides the widest frequency bandwidth of
operation before retuning is necessary (very useful if you're moving
up and down the SSB portion of the band, for example)..."

They are correct when they say that there is only one setting for a
match, but the L-network Q is set by the load and source Z and is
likewise fixed and totally out of the control of the operator. This
may or may not give the largest operating BW and/or lowest loss.

For example, take a load Z of 5 -j10 at 7 MHz. With capacitor Q =1000
and inductor Q = 250 (good luck with a roller inductor), an L-network
of C = 1364 pF and L =0.568 uH will give SWR = 1.02. The network loss
will be 0.1 dB.

Using the same load Z and component Q, a high-pass-Tee network of Cin
= 1438 pF, L = 0.36 uH and Cout = 3912 pF will give SWR = 1.01 The
network loss will be 0.07 dB.

More parts, lower loss. So much for conventional wisdom. Now this is
a pretty wild load Z, but with certain antenna feedpoint Z and
transmission line lengths and Zo, it's possible. Admittedly, the
differences in insertion loss are negligble but they are different in
the -wrong- direction, thus proving the point.

Of course, try and find a tuner with capacitors of this high a value.

Also, there are some impedances that cannot be matched with either
configuration of a low-pass (series inductor) L-network. The same can
be said for any other topology, but you should be aware of this.

(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?

I wouldn't do this.

(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?

Maybe. In my opinion balun loss is no different from line
attenuation. Line attenuation is magnified by SWR and I see no reason
why balun loss wouldn't be too, particularly since most baluns are
constructed from a transmission line.

(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?

If you have plenty of room, why limit yourself to one compromise
antenna?