Q about balanced feed line
 

How does one check the balance between two parallel feed wires into a
doublet antenna. Neon bulbs or some sort of meter gizmo?

tnx

d

Q about balanced feed line
 

That topic was discussed in some detail on this newsgroup just a few
weeks ago. Do a search in groups.google.com of this newsgroup for the
topic "unbalance indicator".

Roy Lewallen, W7EL

Big Endian wrote:
How does one check the balance between two parallel feed wires into a
doublet antenna. Neon bulbs or some sort of meter gizmo?

tnx

d

Q about balanced feed line
 

How does one check the balance between two parallel feed wires into
a
doublet antenna.

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

Just go out into the garden and look up at the antenna.

If each half of the doublet is of about the same length, and both
halves are about the same height above ground, then the parallel pair
of wires are balanced.
----
Reg.

Q about balanced feed line
 

Big Endian wrote:

How does one check the balance between two parallel feed wires into a
doublet antenna. Neon bulbs or some sort of meter gizmo?

tnx

d

YEP!!

An RF Ammeter will do just fine

Q about balanced feed line
 

Amos Keag wrote:

YEP!!

An RF Ammeter will do just fine

Balance requires that the currents in the two wires be equal in
magnitude and opposite in phase (or direction). How do you connect an RF
ammeter to determine this?

Roy Lewallen, W7EL

Q about balanced feed line
 

Wouldn't the clamp-on type ammeter as discussed previously provide that
information (provided a section of twin lead small enough to fit the
clamp were used?

Chuck

Roy Lewallen wrote:
Amos Keag wrote:


YEP!!

An RF Ammeter will do just fine


Balance requires that the currents in the two wires be equal in
magnitude and opposite in phase (or direction). How do you connect an RF
ammeter to determine this?

Roy Lewallen, W7EL

Q about balanced feed line
 

"Roy Lewallen" wrote
Balance requires that the currents in the two wires be equal in
magnitude and opposite in phase (or direction). How do you connect
an RF
ammeter to determine this?
=====================================

It's unbelievably easy Roy, you just pass both wires together through
a clamp-on ammeter.
----
Reg.

Q about balanced feed line
 

Reg Edwards wrote:
How does one check the balance between two parallel feed wires into
a
doublet antenna.

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

Just go out into the garden and look up at the antenna.

If each half of the doublet is of about the same length, and both
halves are about the same height above ground, then the parallel pair
of wires are balanced.

In your opinion.

But the original questioner wants to measure what's *really* happening.


--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

Q about balanced feed line
 

Big Endian wrote:
How does one check the balance between two parallel feed wires into a
doublet antenna. Neon bulbs or some sort of meter gizmo?

The easiest way is to use a large sampling toroid such
that the balanced line can be fed through the toroid.
A ten-turn sampling coil will indicate any unbalance.
Note that the balanced line needs to be centered with
respect to the toroid and needs to be moved along the
feedline to obtain maximum accuracy. Ideally, the toroid
needs to be located at a standing wave current maximum
point. Since my choke-balun is always located at a current
maximum point, I can easily monitor my feedline balance.

You can also use smaller toroids on each line and then
superpose the two readings. But the two toroids need to
be identical which is no small requirement.
--
73, Cecil http://www.qsl.net/w5dxp

Q about balanced feed line
 

Reg Edwards wrote:
If each half of the doublet is of about the same length, and both
halves are about the same height above ground, then the parallel pair
of wires are balanced.

What if one is broken and you don't know it?
--
73, Cecil http://www.qsl.net/w5dxp