[TowerTalk] common mode chokes, baluns and multiband doublets

David Gilbert xdavid at cis-broadband.com
Mon Dec 11 21:18:04 EST 2017

There are a lot of reasons why window line is not a good idea, but it's 
totally wrong to say that a common mode choke will choke the signals on 
window line.   I really don't understand why you would say that.  The 
fields generated by each wire for a signal traveling along window line 
oppose each other ... there is no field to choke if the currents are 
equal (i.e., the line is balanced).  And if the currents are not equal, 
then the common mode choke more or less forces them to be equal ... just 
like a common mode choke is supposed to.

Dave   AB7E

On 12/11/2017 5:15 PM, Bert wrote:
> We're talking about a common mode choke, not a balun/transformer.
> Bert, VE3NR
> On 12/11/2017 7:08 PM, Wes N7WS wrote:
>> Actually that's not true. A lot of baluns are wound with balanced 
>> transmission line.
>> Wes. N7WS
>> Sent from my iPhone
>>> On Dec 11, 2017, at 3:49 PM, Bert <balmemo at sympatico.ca> wrote:
>>> Hi Bill,
>>> Choking the window line is not a good idea - you'll choke the 
>>> signals too. Common mode chokes are mainly used for coax cables and 
>>> multi-conductor cables. I'm sure you'll get many more detailed 
>>> replies from the experts.
>>> Good Luck!
>>> Bert, VE3NR

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