Thanks Reg, i already have such a tuner but never thought it would be usful
with varying impedances.
I hope 2006 will be good for you too...
Greetings Johan PE1AEQ

"Reg Edwards" schreef in bericht
...

"johan aeq" wrote
So a simple "pi filter" withe a bulun will do the same?
I always thought that the wide impedancerange of open wire made a
currentbalun or voltagebalun unusable.
I was just gathering parts to build my own balanced tuner....
Greetings Johan PE1AEQ

==========================================
All kinds of peculiar things can happen with voltage baluns and
current baluns which have a definite impedance ratio.

But my comments apply to a CHOKE balun, the most simple form of balun.
It is a pair of wires wound together on a ferrite ring. It is just a
very short 2-wire transmission line. For longitudinal currents it is
an RF choke, the 2 wires being effectively connected in parallel.

The impedances between which it can work are indeterminate. There is
no impedance ratio.

When connected between a balanced line and an unbalanced tuner, the
tuner can be an ordinary simple L, Pi or T network.

If you happen to have a balanced tuner, lying around doing nothing,
then by all means use it without a balun. But if you don't have a
balanced tuner, as is very likely, there's no need to make one. Just
use a common or garden unbalanced tuner, which nearly everybody has
already got, with a CHOKE balun.

The hardest part of making a choke balun is obtaining the ferrite
ring. 50mm outside diameter, 30mm inside diameter, permeability
200-400, about 16 turns of twin, flexible, stranded, speaker cable,
will be OK for the HF bands. Or similar.

All the very best for 2006.
----
Reg, G4FGQ.

On Mon, 2 Jan 2006 14:56:49 +0000 (UTC), "Reg Edwards"
wrote:

Why use a balanced tuner when a less expensive, easier to operate,
unbalanced tuner, in conjunction with a simple choke-balun, will do
just as well?

Insert the 2-wire choke-balun between the unbalanced tuner and the
balanced transmission line.
----
Reg.


My link coupled tuner (Johnson Matchbox) cost me less than 60 USD, I
can tuner faster than a T-type tuner, doesn't need nor use a balun.
(Read one less component and its associated loss). So why would I want
to replace it with something that works almost as good?

Danny,
K6MHE



email: k6mheatarrldotnet
http://www.k6mhe.com/

Dan Richardson wrote
My link coupled tuner (Johnson Matchbox) cost me less than 60 USD, I
can tuner faster than a T-type tuner, doesn't need nor use a balun.
(Read one less component and its associated loss). So why would I
want
to replace it with something that works almost as good?

Danny,
K6MHE
==========================================
Danny Boy,

If you are happy with your link-coupled tuner, which can be either
balanced or unbalanced, then by all means stick with it. I must admit
it is something I forgot about.

Many years back I had a similar commercial tuner. It didn't cover
enough bands for me. So I dismantled it. The only parts worth
recovering were the slow-motion variable capacitor drives and the nice
skirted tuning knobs. Which I still have. They are of sentimental
value.

Ever since then I have used only home-brewed tuners with coils and
capacitors connected with universal alligator clips. But never of the
balanced variety.

I wish you the very best of DX for 2006.
----
Reg, G4FGQ.

On Mon, 02 Jan 2006 10:20:30 -0800, Dan Richardson wrote:

On Mon, 2 Jan 2006 14:56:49 +0000 (UTC), "Reg Edwards"
wrote:

Why use a balanced tuner when a less expensive, easier to operate,
unbalanced tuner, in conjunction with a simple choke-balun, will do
just as well?

Insert the 2-wire choke-balun between the unbalanced tuner and the
balanced transmission line.
----
Reg.


My link coupled tuner (Johnson Matchbox) cost me less than 60 USD, I
can tuner faster than a T-type tuner, doesn't need nor use a balun.
(Read one less component and its associated loss). So why would I want
to replace it with something that works almost as good?

I use my 500+ foot horizontal loop on 6 and 2 meters with homebrew
balanced tuners from the '63 ARRL Handbook. On HF a balanced double-L
tuner does the trick. The balanced-L tuner does use a balun but it is
between the rig and the matching device. The only problem with using
the Johnson Matchbox is 30M

73 de n4jvp
Fritz

Put a 500-pF variable capacitor in series with the link inside or, outside
the enclosure in series with the center conductor of the coax line feeding
the JMBox. Gives you an extra degree of freedom in tuning.
73, Dave, N3HE

SNIP
between the rig and the matching device. The only problem with using
the Johnson Matchbox is 30M

73 de n4jvp
Fritz