On 8/24/2023 9:41 PM, Wes Stewart via Topband wrote:
I worked my first 80 countries on 160 using an inverted-vee dipole, apex at 45
feet, ends down around 6-10 feet. TX power = 500W, dipole used for both TX and
RX.
I think this qualifies a NVIS.
NVIS is a mode of propagation, not an antenna. That optimum height
produces the greatest radiation straight up. That doesn't mean there's
NOTHING at low angles, rather that a horizontal antenna that's higher
(up to about a half-wave, when higher starts to lobe) will provide
greater field strength at low angles.
On 8/24/2023 6:57 PM, Don Kirk wrote:
> During 160 meter contests I often experience situations where I can
barely
> hear a station calling me on my 68 foot base loaded vertical which I use
> for transmit but when I switch to any one of my receive pennant antennas
> they are often 20db or much more over my noise floor and this typically
> happens when the station is within 150 or so miles of my QTH.
Right. Transmit is about efficiency, Receive is about signal to noise
ratio. Also, some RX antennas are high angle antennas. I think I
remember that Beverages are.
And we all know that vertical arrival angles vary with propagation.
I don't know enough about 160M propagation to know whether paths are
always reciprocal -- that is, if a signal ARRIVES at a high angle, will
my most efficient transmit path to him be at that high angle.
73, Jim K9YC
_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
|