I'm searching the formula for
a inverted V diple; the angle
is 60°.

I was wondering if at such
angle the bandwith decreases.

==========================

What would you like calculate ?

What is your definition of 'bandwidth' ?

Are you concerned only with what the SWR meter is supposed to be measuring ?

Bandwidth depends as much on transmission line and matching arrangements, if
there are any, as on the V itself. Changing the apex angle is just as likely
to increase as to decrease bandwidth, depending on what it is before any
changes are made.

Download from following website in a few seconds program INV_VEE and run
immediately. It will estimate most characteristics of a 1/2-wave resonant
inverted-V, including input impedance of the dipole and of the input
impedance, R+jX, of the transmission line at the transmitter end.

BTW, although it may be possible to minimise SWR on the feedline by varying
apex angle, overall result may be a loss in efficiency. Relative to a
horizontal dipole the V has a lower radiation resistance and a higher ground
loss resistance. The effects interact with each other. The program
demonstrates. All dimensions and angle can be varied "What-if ? "
----
=======================
Regards from Reg, G4FGQ
For Free Radio Design Software
go to http://www.g4fgq.com
=======================

On Sun, 13 Jul 2003 13:12:57 +0000 (UTC), "Reg Edwards"
wrote:

It will estimate most characteristics of a 1/2-wave resonant
inverted-V,

Thank you for this great software.
I didn't understand some input:

S: Soil resistivity, ohm-metres
Which item to input if antenna is on
a roof?

H: Height of ends, metres ......
Is it the height from feedpoint
and the roof or from feedpoint
and ground?

Thanks again

--
togli la spina x risponder mi !!!

S: Soil resistivity, ohm-metres
Which item to input if antenna is on
a roof?
----------------------------------------------

If it's corrugated iron then enter 0, Sea water or Very good.
If it's timber then enter 500 or Very Poor.

---------------------------------------------

H: Height of ends, metres ......
Is it the height from feedpoint
and the roof or from feedpoint
and ground?

------------------------------------------

Nothing to do with feedpoint.

The 'ends of the wire' are the ends of the wire.

Height of the ends above ground level is the height of the ends above the
roof - which so far as the antenna is concerned IS the ground.

Raise the height of the ends by 1 metre and the whole triangular shape,
including the apex, increases in height by 1 metre. That way you have
nothing to worry about. The length of the dipole and the apex angle remain
unchanged.

To vary the apex angle, vary the straight-line distance between the dipole
ends and the dipole length will remain unchanged.

Input variables can be swept by up/down keyboard keys between their extreme
values. All can be done in a second or two.

Set the apex angle to 180 degrees and you have the performance of an
ordinary 1/2-wave resonant dipole with its feedline, either coax, ladderline
or open wire.
---
Reg