Topband: Shunt Fed Tower Info

Roger Mulzer rmulzer at ger.ibb.gov
Mon Aug 4 14:37:39 EDT 2003


Hello Bill,

the tower including top loading is definitely not too tall. 230 ft equal roughly halfwave lambda on 1.8 MHz.
High angle radiation would start at a height of 350 ft. However if you want to suspend reflector/director 
wires from top of the tower the exact current distribution which is hard to predict with top loading and
especially more "in between loading" is the critical point in getting deep nulls to the back or side.

Its not simply an adaption of quarterwave phased or parasitic array techniques but more a cut and try 
which doesnt mean careful thinking and planning wouldnt get you close to good results. The "fine tuning"
always has to be done in reality.

73s and good luck

Roger, DL5RBW


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