dear friend
on your design you have toe , sigma and R........toe 0.8-0.95 sigma 0.05-0.2 R 50 or 75 ohms
first- calculate za =60 ln{ (16 k toe sigma)/[pi (1+toe)]}
k is average ratio of elements LENGTH to DIAMETER.for better resault you may slim elements to be constant k.
ln is natural logarithm.
second- x={R(1+toe)/(32 sigma toe za)}
zo=R[x+square (x power2 +1)]
zo is the characteristic impedance of boom line.
if you use round tube diameter d and distance between centers D....zo=276 log (D/d)
if you use square tube side a equivalent diameter is 1.06 a
so if you choose tube you will find separation between them.you are free to ask more. juji tabrizi
---------- Post added at 07:11 ---------- Previous post was at 06:12 ----------
dear friend
on your design you have toe , sigma and R........toe 0.8-0.95 sigma 0.05-0.2 R 50 or 75 ohms
first- calculate za =60 ln{ (16 k toe sigma)/[pi (1+toe)]}
k is average ratio of elements LENGTH to DIAMETER.for better resault you may slim elements to be constant k.
ln is natural logarithm.
second- x={R(1+toe)/(32 sigma toe za)}
zo=R[x+square (x power2 +1)]
zo is the characteristic impedance of boom line.
if you use round tube diameter d and distance between centers D....zo=276 log (D/d)
if you use square tube side a equivalent diameter is 1.06 a
so if you choose tube you will find separation between them.you are free to ask more. juji tabrizi