Any reason I shouldn't use a choke balun out of my tuner to feed ladderline
up to a dipole?

Any reason I shouldn't use a choke balun out of my tuner to feed
ladderline
up to a dipole?

====================================

There's no reason whatsoever. In fact it is the obvious thing to do.

The choke allows you to connect an unbalanced tuner to any balanced
feedline via the choke.

A balanced tuner is entirely unnecessary in almost all circumstances.

The choke is simply a pair of wires wound together around a ferrite
toroid. Or it is a coaxial pair wound round a toroid (which for
various reasons is slightly less efficient and is physically less
convenient.) So the pair of parallel wires is the better form of
construction.

The choke behaves as a short length of transmission line of the same
length as the pair of wires wound on the choke. Which is very short
when a ferrite toroid is used.

Because the length of line is an impedance transformer it transforms
the input impedance of the transmission line to somewhat different
values especially at the higher frequencies. At the lower frequencies
it may just as well not be there.

Which means that the tuner L and C settings are different to those
which occur when the choke is not there. But often, when the choke is
in use, the tuner finds it easier to match the line and antenna to the
transmitter. Which is the sole purpose of the tuner.

The number of turns wound on the choke must provide an inductance and
a reactance of about 4 or 5 times the load resistance required by the
transmitter, usually 50 ohms, at the lowest frequency of operation.
This depends on the permeability of the ferrite core material.

At the higher frequencies it is best that the length of line wound on
the torroid should not exceed 1/8th of a wavelength at the free-space
velocity. This is usually not too difficult to manage.

To simplify, get a 2" outside diameter ferrite ring, of HF grade
marerial, wind on 14 or 18 turns, and get on with it.

A choke balun is the most simple of radio components to construct, yet
its behaviour is amongst the most complicated of components to
analyse.
----
Reg, G4FGQ.

"Reg Edwards" wrote in message
...

Any reason I shouldn't use a choke balun out of my tuner to feed
ladderline
up to a dipole?

====================================

There's no reason whatsoever. In fact it is the obvious thing to do.

The choke allows you to connect an unbalanced tuner to any balanced
feedline via the choke.

A balanced tuner is entirely unnecessary in almost all circumstances.

The choke is simply a pair of wires wound together around a ferrite
toroid. Or it is a coaxial pair wound round a toroid (which for
various reasons is slightly less efficient and is physically less
convenient.) So the pair of parallel wires is the better form of
construction.

The choke behaves as a short length of transmission line of the same
length as the pair of wires wound on the choke. Which is very short
when a ferrite toroid is used.

Because the length of line is an impedance transformer it transforms
the input impedance of the transmission line to somewhat different
values especially at the higher frequencies. At the lower frequencies
it may just as well not be there.

Which means that the tuner L and C settings are different to those
which occur when the choke is not there. But often, when the choke is
in use, the tuner finds it easier to match the line and antenna to the
transmitter. Which is the sole purpose of the tuner.

The number of turns wound on the choke must provide an inductance and
a reactance of about 4 or 5 times the load resistance required by the
transmitter, usually 50 ohms, at the lowest frequency of operation.
This depends on the permeability of the ferrite core material.

At the higher frequencies it is best that the length of line wound on
the torroid should not exceed 1/8th of a wavelength at the free-space
velocity. This is usually not too difficult to manage.

To simplify, get a 2" outside diameter ferrite ring, of HF grade
marerial, wind on 14 or 18 turns, and get on with it.

A choke balun is the most simple of radio components to construct, yet
its behaviour is amongst the most complicated of components to
analyse.
----
Reg, G4FGQ.