As commonly used (as on this thread), takeoff angle is a property of an
antenna, meaning the angle at which the antenna gain is maximum. What
does that have to do with the angle of the wave being used for
communication? Does changing the takeoff angle of your antenna somehow
magically change the height of the ionosphere?

Let's say the wave angle for communication is ten degrees. I have one
antenna with a takeoff angle of ten degrees and another with a takeoff
angle of 20 degrees. Which is better?

Roy Lewallen, W7EL

Cecil Moore wrote:
Roy Lewallen wrote:

Can someone please explain to me why a lower takeoff angle is better?


Quoting from an old ARRL Antenna Book:

"Rays entering the ionized region at angles above the critical
angle are not bent enough to be returned to Earth, and are lost
in space."

"A significant loss of signal occurs with each hop. ... Assuming
that both waves do reach the same point, the (one-hop) low-angle
wave will contain more energy" (than the two-hop higher angle wave).
--
73, Cecil, W5DXP

Roy Lewallen wrote:
As commonly used (as on this thread), takeoff angle is a property of an
antenna, meaning the angle at which the antenna gain is maximum.

We've been through all this before with references being provided to
prove that the definition of "take-off-angle" is not limited to the
angle of maximum antenna gain.
--
73, Cecil, W5DXP

Please check the context of its use in this thread.

Roy Lewallen, W7EL

Cecil Moore wrote:
Roy Lewallen wrote:

As commonly used (as on this thread), takeoff angle is a property of
an antenna, meaning the angle at which the antenna gain is maximum.


We've been through all this before with references being provided to
prove that the definition of "take-off-angle" is not limited to the
angle of maximum antenna gain.
--
73, Cecil, W5DXP

Roy Lewallen wrote:
Please check the context of its use in this thread.

I apologize if I missed the context. I don't read all the articles
and sometimes jump into the middle of a thread, ill equipped for
comprehending the context.

But, to answer your earlier question: Why is take-off-angle important?
Consider a 1/4WL 80m vertical used on 10m and you will know why.
--
73, Cecil http://www.qsl.net/w5dxp



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Dumb question:
What about using 2 different loops. One inside of the other. Do the
320 & the 80 inside of it. Who has tried this?
Ed
KB1DQX

Well, the answer is, it depends...

As you increase the length of a horizontal loop, it will have lower angle lobes
that exhibit some slight gain on frequencies HIGHER than the fundamental
frequency. The gain might not be dramatic but the lower angle of radiation is
a plus.

For multiband operation, the inverted L is not recommended in most cases. On
its fundamental frequency, it is a nice, all around antenna since you get high
angle radiation from the horizontal portion and vertical, lower angle radiation
from the vertical section. However, depending on bands of operation, you can
get phase interference from the vertical and horizontal sections that might be
undesirable. Each situation is site specific and band specific.

What you will notice is that the horizontal loop will have 1-2 s units lower
noise than a vertical or inverted, based upon my empirical data collected over
a three year period with a vertical and loop in the same region.

Enjoy your antenna experiments.

73s,

Evan

Let me restate my goal.

Here is my situation. I live in Northern MI & have 5+ acres of mostly woods
with many hardwood trees averaging 60'. I also have about 1500'of wire & a 3
element tribander for 10-15 & 20. I use a 100 watt transceiver - no amp. I
live in a rural, low-noise environment.

I also want to work 160, 80/75, 40, &17. I don't mind doing separate wire
antennas for these bands but would prefer 1 antenna. I have a homebrew
link-coupled tuner that covers 160-17 (plug in link-coils).

I want to work stateside & DX on 160 & 75 & 17.

What is the best use of my 1500' of wire to achieve my goals.

TNX

Terry
W8EJO






"T.E.O" wrote in message
hlink.net...
I am going to put up a horizontal loop @ about 60' in hopes of having a
decent 160-10 antenna. Is there any adavntage to increasing the the total
length from 1 wavelength at the lowest freq. (about 530') to 2
wavelengths(1,060'). i have the space & the wire & I'm wondering if it's
worth the extra effort.

Also, am I better off with a 3/8 WL inverted L on 160.

Terry,
I'd use as much of your wire I could, and get it as high as
possible. Ought to work pretty good on 160 meters. and not bad
on the other bands. With the link tuned (balanced?) tuner, it
should 'go' just about anywhere. May not have the lowest 'take-
off'/radiation angle, but who cares? No single antenna is going
to be 'good' everywhere.
'Doc