On 2/10/2013 7:34 AM, Channel Jumper wrote:
tom;801584 Wrote:
snip


Your problem is - you want to use a choke with a off center fed
antenna.
Either to reduce the RF going into the shack or to reduce noise.
If you really want to work DX, you don't want to use a choke.
It would be better to use a BALUN / transformer before the coax enters
the shack then to use a choke.


Please explain the difference between a choke and a balun in this situation.

tom
K0TAR

A balun is an electrical device that converts between a balanced signal (two signals working against each other where ground is irrelevant) and an unbalanced signal (a single signal working against ground or pseudo-ground). A balun can take many forms and may include devices that also transform impedances but need not do so. Transformer baluns can also be used to connect lines of differing impedance. The origin of the word balun is balance + unbalance.

Generally a balun consists of two wires (primary and secondary) and a toroid co it converts the electrical energy of the primary wire into a magnetic field. Depending on how the secondary wire is done the magnetic field is converted back to a electric field.

A Choke - is simply a piece of coax or wire which is wound at the mininum bend radius of the coax. Several turns of coax makes a simple choke.
You have to be very careful not to open up the shield by winding it too tightly.

Baluns can take many forms and their presence is not always obvious. Sometimes, in the case of transformer baluns, they use magnetic coupling but need not do so. COMMON MODE CHOKES ARE ALSO USED AS BALUNS! and work by eliminating, rather than ignoring, common mode signals.

The key word there is - used as baluns.
If it was a Balun - they would call it a Balun

Coax works on the principal of a Faraday Cage.

Maybe you would like to explain for the people on this forum what a Faraday Cage is?

On Tue, 12 Feb 2013 13:36:32 +0000, Channel Jumper
wrote:

A balun is an electrical device that converts between a balanced signal
(two signals working against each other where ground is irrelevant) and
an unbalanced signal (a single signal working against ground or
(...)

http://en.wikipedia.org/wiki/Balun
Please provide a citation when plagerizing.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 2/12/2013 1:08 PM, Jeff Liebermann wrote:
On Tue, 12 Feb 2013 13:36:32 +0000, Channel Jumper
wrote:

A balun is an electrical device that converts between a balanced signal
(two signals working against each other where ground is irrelevant) and
an unbalanced signal (a single signal working against ground or
(...)

http://en.wikipedia.org/wiki/Balun
Please provide a citation when plagerizing.



He also didn't answer the question I asked, which would have been a much
much shorter answer.

tom
K0TAR