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Old April 16th 08, 08:41 PM posted to rec.radio.amateur.antenna
Richard Clark Richard Clark is offline
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First recorded activity by RadioBanter: Jul 2006
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Default Linear decoupling traps

On Wed, 16 Apr 2008 21:53:39 +0300, "JN" wrote:

Here is what I mean:

http://farm3.static.flickr.com/2208/...7fd3ba40_o.jpg

Measures taken from hat, but if one could say the resonance points and
impedances I would be grateful
Originally I asked the difference if you turn the stub 180 degrees.


Hi Jouko,

If we are looking at four wire segments to the left of the center of
the dipole, then this is a lattin design element. All my comments
about that stand.

As for speculating where it resonates, there is not enough
dimensioning to be exact (while there is little enough to make a poor
guess).

I would only ask, do you want it to act as a trap such that the
radiating portion of the antenna is confined to the right (as
illustrated in your link) of this construction (like a conventional
trap for a dual band operation)? Or do you want the element to act as
linear loading to make the entire structure resonate at a shorter
physical length?

If you turn the element, yes, it will make a difference. There is
still a long road to travel to make it "work" and it probably won't
look like your link's illustration and it won't resonate where you
expect it to.

You still have to observe the separation of the two lines by at least
3 times the largest diameter wire/rod.

73's
Richard Clark, KB7QHC