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1/4 wave ?

When not active, the element lengths are made to appear longer by the quarter wave coax sections. If
the coax does not add the correct amount of inductance, the elements will not act as reflectors and
the pattern will be an oval shape with equal gain front and back. Computer modelling shows the
following required amounts.
20 m    1mh and 5 pf
17 & 15 m   .8    6.25
12 & 10 m   .6    8.3
6 m    .1    50
2m .1    5
440mhz .03 1
For omni postion the original scanner directions give a series capacitor of 250pf and a 9 turn inductor.
I do not know the diameter or length of the coil but it must be under 1 mh. Older versions had a simpler way of just adding a quarter wave matching stub . This was shorted out at the end and left dangling down the mast.

<blockquote data-quote="nitroturbo4u" data-source="post: 418270" data-attributes="member: 30119">1/4 wave&nbsp; ?When not active, the element lengths are made to appear longer by the quarter wave coax sections. If the coax does not add the correct amount of inductance, the elements will not act as reflectors and the pattern will be an oval shape with equal gain front and back. Computer modelling shows the following required amounts. 20 m&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; 1mh&nbsp; and 5 pf17 &amp; 15 m&nbsp;&nbsp; .8&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; 6.2512 &amp; 10 m&nbsp;&nbsp; .6&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; 8.36 m&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; .1&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; 502m&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; .1&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; 5440mhz&nbsp; &nbsp; &nbsp; .03&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 1For omni postion the original scanner directions give a series capacitor of 250pf and a 9 turn inductor.I do not know the diameter or length of the coil but it must be under 1 mh. Older versions had a simpler way of just adding a quarter wave matching stub . This was shorted out at the end and left dangling down the mast.<img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f600.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":D" title="Big Grin&nbsp; &nbsp; :D"&nbsp; data-smilie="8"data-shortname=":D" /></blockquote>

[QUOTE="nitroturbo4u, post: 418270, member: 30119"] [b]1/4 wave ?[/b] [B][I][COLOR="Blue"][/COLOR][/I][/B]When not active, the element lengths are made to appear longer by the quarter wave coax sections. If the coax does not add the correct amount of inductance, the elements will not act as reflectors and the pattern will be an oval shape with equal gain front and back. Computer modelling shows the following required amounts. 20 m 1mh and 5 pf 17 & 15 m .8 6.25 12 & 10 m .6 8.3 6 m .1 50 2m .1 5 440mhz .03 1 For omni postion the original scanner directions give a series capacitor of 250pf and a 9 turn inductor. I do not know the diameter or length of the coil but it must be under 1 mh. Older versions had a simpler way of just adding a quarter wave matching stub . This was shorted out at the end and left dangling down the mast. :D [/QUOTE]

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