> If you prolong the mast lenght from 60 ft. To a 80m 3/8 wl. And combine
> it with a top or linearloading to resonate 160m (better than the coil)
> then you will be able to utilise your "relatively" short ground space'
While a person experienced in phasing system design can work around it, that
will cause problems. The simple "equal current" feed will no longer work
with base fed radiators electrically longer than 1/4 wl. The rule of equal
currents at the base no longer applies, so any conventional feed system
design will not work.
I also would use some form of properly designed hi-Q lumped loading or be
very careful with linear loading.
Linear loading often adds unnecessary loss. If improperly implemented it can
also ruin the equal "current forcing rule" all common phasing designs
require.
> available in a better way from point of minimising ground losses on the
> 80 m section as increased (3/8) wl. Will heighten the current maximum.
...and that is what destroys the commonly applied "current forcing rule".
Equal currents into the base of each vertical will no longer provide maximum
null depth and gain. The rule about equal currents at the feedpoint is only
valid when the antenna is series-fed at the point of current maxima in the
element.
Another rule, less often heard, is voltage fed elements require equal
voltages.
When you shunt feed or otherwise feed elements other than at current or
voltage maxima, each element will require dissimilar feedpoint current or
voltage for maximum gain and null depth. That complicates the feed system,
unless you don't want peak performance.
You can phase anything and make it work, but the rules very often change
with how the elements are configured.
73 Tom
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