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starduster,

in your pics you have the coaxial fastened down the side of the mast,
the radials beside the mast form a tapered transmissionline whos   impedance is the dominant factor in determining the antennas input impedance,

transmissionline impedance is determined by mast and radial tube   diameters / spacing and the electrical length of said transmissionline,
i don't know how much offsetting the coax to one side effects impedance when the mast is present, it may have very little effect,
ideally the coaxial should be taped dead central between the radials as shown in the assembly instructions,

tuning the astroplane is not so simple as tweaking element lengths   although that may give you a low vswr

<blockquote data-quote="bob85" data-source="post: 208282" data-attributes="member: 18">starduster,&nbsp;in your pics you have the coaxial fastened down the side of the&nbsp; mast,the radials beside the mast form a tapered transmissionline whos&nbsp;&nbsp; impedance is the dominant factor in determining the antennas input impedance, transmissionline impedance is determined by mast and radial tube&nbsp;&nbsp; diameters / spacing and the electrical length of said&nbsp; transmissionline,i don&#039;t know how much offsetting the coax to one side effects impedance&nbsp; when the mast is present, it may have very little effect,ideally the coaxial should be taped dead&nbsp; central between the radials as shown in the assembly instructions,tuning the astroplane is not so simple as tweaking element lengths&nbsp;&nbsp; although that may give you a low vswr<img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f44d.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":thumbup1:" title="Thumbs Up&nbsp; &nbsp; :thumbup1:"&nbsp; data-smilie="27"data-shortname=":thumbup1:" /></blockquote>

[QUOTE="bob85, post: 208282, member: 18"] starduster, in your pics you have the coaxial fastened down the side of the mast, the radials beside the mast form a tapered transmissionline whos impedance is the dominant factor in determining the antennas input impedance, transmissionline impedance is determined by mast and radial tube diameters / spacing and the electrical length of said transmissionline, i don't know how much offsetting the coax to one side effects impedance when the mast is present, it may have very little effect, ideally the coaxial should be taped dead central between the radials as shown in the assembly instructions, tuning the astroplane is not so simple as tweaking element lengths although that may give you a low vswr:thumbup1: [/QUOTE]

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