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eddie,
the big-mac was tunable by moving the tap on the lower coil and by altering the length of the upper 5/8wave, the length of the lower 1/4wave and phasing coil were fixed,

i would not call the performance deficient, , im saying that the small physical separation between the two active elements may not be making the most of the 5/8 over 1/4wave co-linear's potential,
the mac has no problem outperforming any single element groundplane,

the one in the photo is in a sorry state with its basket bent out of shape

i don't know exactly whats going on with the sigma, let me get my head round tm / tem wave propagation and common mode excitation in tapered transmissionlines lol

<blockquote data-quote="bob85" data-source="post: 279307" data-attributes="member: 18">eddie,the big-mac was tunable by moving the tap on the lower coil and by altering the length of the upper 5/8wave, the length of the lower 1/4wave and phasing coil were fixed,i would not call the performance deficient, , im saying that the small physical separation between the two active elements may not be making the most of the 5/8 over 1/4wave co-linear&#039;s potential, the mac has no problem outperforming any single element groundplane,the one in the photo is in a sorry state with its basket bent out of shapei don&#039;t know exactly whats going on with the sigma, let me get my head round tm / tem wave propagation and common mode excitation in tapered transmissionlines lol <img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f642.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":)" title="Smile&nbsp; &nbsp; :)"&nbsp; data-smilie="1"data-shortname=":)" /></blockquote>

[QUOTE="bob85, post: 279307, member: 18"] eddie, the big-mac was tunable by moving the tap on the lower coil and by altering the length of the upper 5/8wave, the length of the lower 1/4wave and phasing coil were fixed, i would not call the performance deficient, , im saying that the small physical separation between the two active elements may not be making the most of the 5/8 over 1/4wave co-linear's potential, the mac has no problem outperforming any single element groundplane, the one in the photo is in a sorry state with its basket bent out of shape i don't know exactly whats going on with the sigma, let me get my head round tm / tem wave propagation and common mode excitation in tapered transmissionlines lol :) [/QUOTE]

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