Topband: "Linear Loading" & 160-Meters

[Edward Swynar]

On 23rd February, Jerry wrote:

"...The feedpoint impedance was 13.5 ohms.
 (Feedpoint impedance of the full size bobtail was 41 ohms.). Of course you
can feed these from the bottom of the center element too, but I didn't
simulate that..."

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Hi Jerry,

>From the sound of things, the antenna you modelled there was the INVERTED
Bobtail array (or, as it was dubbed in an early edition of the ARRL's
"ANTENNA COMPENDIUM", the "Robert Tail Array")...

The classic Bobtail, per se, is voltage fed---at the tip of the centre
vertical element---and has a very high impedance feedpoint, whereas the
Robert Tail is fed at the juncture of the centre vertical wire & the
counterpoise wire linking all three elements together (hence the lower
feedpoint impedance)...

Still, your analysis is interesting: I'm sure the results you modelled would
be very similar if the entire affair was to be inverted 180 degrees, and
regarded as a Robert Tail.

Many thanks for sharing, & my vy

~73!~ de Eddy VE3CUI - VE3XZ