If the elements are of different diameters, example 0.5 inches and 0.375
inches there are differences in Zo and slight differences in Fo.

To a first approximation I calculate 158.5 MHz as resonant point. That
may have a 2 to 3 percent error due to endeffects, L/D ratio etc.

Your calculation is a good as mine.

DD, W1MCE

Richard wrote:

"Richard" wrote in message
...

Hi. Can anyone please confirm for me the resonant frequency of the folded
dipole below?

(I calculate abt. 159.025 Mhz).

L1
------------------------------------
| | L2
--------------x L4 x---------------
L3 L5

Tube diameter = 10mm

L1: 90Cm; 35.43"; 2.953'
L2: 70mm; 2.76"; 0.230'
L4: 5.8Cm; 2.28"; 0.190'
L3&L5: 42.1Cm; 16.57"; 1.381'




As to calculators,I found two, but they are confusing to me.

Not very clear to me how to use this one:

http://n-lemma.com/calcs/dipole/fdipole.htm

Or this one:

http://www.optcom.net.au/wireless/folded_dipole.html