[600MRG] Resonant frequencies and loaded antennas

[Kenneth G. Gordon]

On 14 Sep 2015 at 21:20, dick.bingham wrote:

> Hi Ken

Hello, Dick.
 
> Regarding your ===> 
> https://www.arrl.org/files/file/Technology/tis/info/pdf/9207035.pdf
> ================
> I examined the traps at the website you provided and am puzzled by the
> description given in the July 1992 QST article AND the follow-up September 1992
> article "making more clear" how to fabricate the trap !!!

Well, you are, most certainly, not alone!!! I found it to be very confusing.
 
> The wiring connections are totally NOT clear to me. As I read both articles, one
> is suppose to strip off the shield from the coax and discard it. Then, one is
> instructed to insert one end of the center-wire wrapped in dielectric into one
> end of the coil form (apparently this forms one connection to an antenna wire.)
> Then one winds a coil along the outside of the form to a second hole on the
> other end of the coil-form where the wire is then inserted into that hole and
> feed back inside the coil-form and routed out of another hole in the coil-form
> close to the beginning hole. Here a second coil-winding is wound on top of the
> first winding and the far-end is routed through a second hole at the far-end of
> the coil. I guess this is the other end of the trap.
> 
> What I do not see is where/how an LC-trap is formed. It just looks like two
> solenoid-wound inductor-windings are formed with some capacitance between
> winding layers.
> 
> Maybe you or one of the group can help me see what is going on here . . .

I found another web site in Europe in which the the author went into great 
detail on the traps, how they are to be made, with very clear drawings. He 
does not, exactly, explain how they work, but he also says that he cannot 
understand how the lengths between the traps were calculated. This last is 
also bugging the heck out of me...

Here is the link:

http://www.i1wqrlinkradio.com/antype/ch37/chiave75.htm

I hope this helps.

There is also this link:

http://www.users.icscotland.net/~len.paget/6_band_inverted_l_antenna.htm
which was provided to me by the ARRLs TIS.

Let me know what you think of this.

Ken W7EKB