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Old January 1st 05, 06:10 PM
Insert66
 
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thanks for the suggestions

I wound up with a BC92XLT
and made a dipole with major improvement


I have a few questions for the gurus

when we say 468 \ mhz = feet

and 234 / mhz = feet



dipole length is the total?

the element length is half that?



what equation would i use to find element length for a half wave?

what equation would i use for quarter wave?

would a full wave dipole be better?

what if the entire antenna was twice full wave long?
would i get better reception? or would i get interferance
as the 2 waves would interfere with one another?


i am only interested in receiving, and only intertested
at this point, in 108 to 136 mhz AM. I am surrounded by buildings
and a transmission towers of every type, in every direction


more questions .. heh

the question of matching the antenna for he frequency you are after

and the idea of matching the antenna ohms to the ohms of the wire
used to feed it

so for a dipole, with elements around 23 inches long
is it best to:

use the same material for the elemenst as the wire that
feeds the antenna?

use 75 oh lead to the antenna


use 50 ohm lead to the antenna

use 300 ohm 2 wire for just the antenna and 50ohms for the lead?

what if i make the dipole of 75 ohm lead and 75 ohm intact coaxial?






and finaly


after thinking about the idea that the lower ground
element and the top pointing driven element should be equal in
impedance, and that the lead should be the same, if one made a dipole
out of coaxial, and split the cable 23 inches from the end, and
dangled the mesh down and the center wirte up, the splitting
of the coaxial would change the ohms of the driven element and the
dangling mesh gound element

so

would you run 2 lines as the feed, one with the driven element as
the center wire and the other coax feed's center wire as the antenna's
ground pointing element? and then at the antenna merely point one
coax down and the other up? with all the bubber and sheilding intact?

I ask this because of this idea of having the same ohms for the
antenna and at the cable that feeds it


thought I'd ask







































TIA for any replies