Now to the original question, in spite of the data in QST, I have
found spreads of less than 15 feet in a practical environment will
not achieve your goal. YMMV.


Again, thanks for the comments. For clarification, though, could you
describe what you mean by the 15 feet spread for a 75M antenna? The QST
author is describing a biconical antenna with two dipoles tied common at
the feedpoint, but spreading out a couple degrees to the ends.... his
figures indicating 6 feet at the ends working, but 15 feet the spread if
using the recommended 2.8 degree angle from the apex.

Is this what you mean, or are you describing two dipoles separated their
full length by 15 feet?


Ed

Ed, spread 15 feet at the ends.Nothing critical once your beyond the 15
feet.

I have varied the lengths of the legs, where one is longer than the other.
For example think of two dipoles one cut for 3.6 and the other cut for 3.8.
I have also played with 4 wires spread 2 vertical and 2 horizontal.

The biconal has been around for ever and was widely used in the old TV
antennas to broadband the response.

If there is any interest, I could dig out my old notebooks and post the SWR
tables of a bunch of designs.


"Ed" wrote in message
. 92.175...


Now to the original question, in spite of the data in QST, I have
found spreads of less than 15 feet in a practical environment will
not achieve your goal. YMMV.


Again, thanks for the comments. For clarification, though, could you
describe what you mean by the 15 feet spread for a 75M antenna? The QST
author is describing a biconical antenna with two dipoles tied common at
the feedpoint, but spreading out a couple degrees to the ends.... his
figures indicating 6 feet at the ends working, but 15 feet the spread if
using the recommended 2.8 degree angle from the apex.

Is this what you mean, or are you describing two dipoles separated their
full length by 15 feet?


Ed

Ed, spread 15 feet at the ends.Nothing critical once your beyond the
15 feet.

I have varied the lengths of the legs, where one is longer than the
other. For example think of two dipoles one cut for 3.6 and the other
cut for 3.8. I have also played with 4 wires spread 2 vertical and 2
horizontal.



Fred, again, thanks for these comments. A 75M broadband biconical
antenna is apparently just what fits my needs and "tree configuration".

Question for you: The QST article does not address whether or not the
two dipoles are cut to different frequencies, as you suggested for your
personal situation you had. Do you think two exact length dipole lengths
are what the QST article author was talking about, or are two different
lengths necessary?

All I am trying to accomplish is put a a full size 75M dipole between
two tall trees (will be about 50' or 60' high dipole) and to have an SWR
across the band that does not exceed about 3:1 .


Ed K7AAT

A biconal has all the legs the same length. I varied the lengths to see if I
could get by with less than 15 feet. It was not successful. A biconal cage
however gets really wide. Less than 2:1 from 3.5 to 4.

As an aside, anecdotally the cage and biconal are both quieter than a
dipole.

"Ed" wrote in message
. 93.175...


Ed, spread 15 feet at the ends.Nothing critical once your beyond the
15 feet.

I have varied the lengths of the legs, where one is longer than the
other. For example think of two dipoles one cut for 3.6 and the other
cut for 3.8. I have also played with 4 wires spread 2 vertical and 2
horizontal.



Fred, again, thanks for these comments. A 75M broadband biconical
antenna is apparently just what fits my needs and "tree configuration".

Question for you: The QST article does not address whether or not the
two dipoles are cut to different frequencies, as you suggested for your
personal situation you had. Do you think two exact length dipole lengths
are what the QST article author was talking about, or are two different
lengths necessary?

All I am trying to accomplish is put a a full size 75M dipole between
two tall trees (will be about 50' or 60' high dipole) and to have an SWR
across the band that does not exceed about 3:1 .


Ed K7AAT

:

A biconal has all the legs the same length. I varied the lengths to
see if I could get by with less than 15 feet. It was not successful. A
biconal cage however gets really wide. Less than 2:1 from 3.5 to 4.


Given the wind potential here, along with loading on my antenna support
lines, I probably should go with the biconical dipole over a cage. I do
have plenty of room to do a 15' end spacing, though.

As an aside, anecdotally the cage and biconal are both quieter than a
dipole.


I hadn't seen any reference to noise benefits from a biconical, so
that's nice to hear! Thanks for the info.


Ed K7AAT