[Antennas] Faraday Loop construction question.

[Brian Cake]

Hi Guys,

    You can look at one of the original loop patents at the USPTO website 
http://patents.uspto.gov/.  Look at patent # 3,588,905.  This will give you 
the basic scheme.

     BTW, "Faraday coupling loop" is a misnomer.  There is no electrostatic 
shielding provided by the described coupling loop.  The arrangement is just 
a clever way of incorporating a balun into the coupling loop. Somewhere down 
the years someone saw a broken braid and said "Ha....Faraday shield" and it 
stuck.

    73

    Brian  KF2YN
----- Original Message ----- 
From: "John Kinnunen" <johnkin at goldengate.net>
To: "Terry Conboy" <n6ry at arrl.net>
Cc: "Antennas Mailing List" <antennas at mailman.qth.net>
Sent: Monday, August 20, 2007 6:04 PM
Subject: Re: [Antennas] Faraday Loop construction question.


> Hi Tarry and all,
>
> As good as the web sight below is, it is only for receiving loops. What 
> about transmitting small magnet tuned loops? Are there any books out that 
> describes both the Faraday loop and the Gamma match so a person can build 
> a loop and get it to work. Also, as good as some web sights are they are 
> often quite short on detail when it comes to the coupling of the antenna 
> to the radio. Even the Antennx loop books are short on detail when it 
> comes to these two coupling method, I have both books.  It would be fun to 
> find a book out there that actually has in theory and practical use how to 
> build a small magnetic tuned loop for transmitting, that is to say if one 
> exists.
>
> John Kinnunen
> KB0ADD
>
>
> Terry Conboy wrote:
>> At 08:29 AM 2007-08-20, Sam Morgan KA5OAI wrote:
>>
>> The center conductor is connected to the outer shield of the left side of 
>> the loop at the midpoint (at the point opposite the feedline).
>>
>> The other end of the shield on the left side is connected only to the 
>> outside of the shield of the feedline.
>>
>> The center conductor inside the left side of the loop need not be 
>> connected to anything (and could even be removed, so obviously, it is 
>> cut).
>>
>> The shield on the right side (at the midpoint) is open circuit (so it is 
>> cut, too.)
>>
>> The current from the center conductor of the feedline flows on the outer 
>> part of the shield on the left side.
>> The current from the inside of the shield of the feedline flows on the 
>> outer part of the shield on the right side.
>> This makes for a reasonably well balanced coupling loop.
>>
>> BTW, the description of small loops as only responding to the magnetic 
>> field is folklore.  See http://www.w8ji.com/magnetic_receiving_loops.htm 
>> for more accurate info (although W8JI doesn't discuss the coupling loop 
>> itself).
>>
>> 73, Terry N6RY
>>
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