Wet ground: it makes 8VSB viable in Canada, but unusuable in Australia ... or when in doubt look back to the basic laws of physics as to why some modulation schemes are better in some nations vs others...

Wet ground: it makes 8VSB viable in Canada, but unusable in Australia ...

When in doubt look back to the basic laws of physics as to why some
modulation schemes are better in some nations vs others...

How wet ground affects other wavelengths
-- Canada's SW relay station at Sackville is next to a wetland, this
provides around 0.5dbi gain (or more)
-- Samara aka Selal-al-Deel (at Balad Air Base) shortwave relay station used
by Iraq until 1990s required 500 kw transmitters to achieve similar reach
with similar antennas

Longwave and wet ground
-- Iceland's RUV longwave frequency seasonally can reach Gatlinburg, TN in
the USA with audible programming... however, Algeria's Bechar LW site has
only succeeded in propagation carrier waves into North America

"Max Power" wrote:

Wet ground: it makes 8VSB viable in Canada, but unusable in Australia
...

Can you elborate on why this is modulation dependent? I realize that wet
and dry ground affect propagation, much like hills and mountains do, and
that wavelength also affects propagation:

http://w3.antd.nist.gov/wctg/manet/propthy_r1.pdf

This seems independent of modulation, though.

When in doubt look back to the basic laws of physics as to why some
modulation schemes are better in some nations vs others...

How wet ground affects other wavelengths
-- Canada's SW relay station at Sackville is next to a wetland, this
provides around 0.5dbi gain (or more)
-- Samara aka Selal-al-Deel (at Balad Air Base) shortwave relay
station used by Iraq until 1990s required 500 kw transmitters to
achieve similar reach with similar antennas

Longwave and wet ground
-- Iceland's RUV longwave frequency seasonally can reach Gatlinburg,
TN in the USA with audible programming... however, Algeria's Bechar LW
site has only succeeded in propagation carrier waves into North
America

I assume all of these examples are AM?

Bert

In article "Max Power" writes:
Wet ground: it makes 8VSB viable in Canada, but unusable in Australia ...

When in doubt look back to the basic laws of physics as to why some
modulation schemes are better in some nations vs others...

How wet ground affects other wavelengths
-- Canada's SW relay station at Sackville is next to a wetland, this
provides around 0.5dbi gain (or more)
-- Samara aka Selal-al-Deel (at Balad Air Base) shortwave relay station used
by Iraq until 1990s required 500 kw transmitters to achieve similar reach
with similar antennas

Longwave and wet ground
-- Iceland's RUV longwave frequency seasonally can reach Gatlinburg, TN in
the USA with audible programming... however, Algeria's Bechar LW site has
only succeeded in propagation carrier waves into North America


Of course, longwave (low frequency) and shortwave (high frequency)
have different prop characteristics than VHF (very high frequency) and
UHF (ultra high frequency).

LF and HF signals have different prop at different latitudes. Last
I checked, Canada and Iceland were a good deal farther north than Iraq
and Algeria. I think that makes a lot more of the difference than the
wetness of the ground.

Alan

On Fri, 9 Mar 2007 00:33:58 -0800, "Max Power"
wrote:

Wet ground: it makes 8VSB viable in Canada, but unusable in Australia ...

When in doubt look back to the basic laws of physics as to why some
modulation schemes are better in some nations vs others...

How wet ground affects other wavelengths
-- Canada's SW relay station at Sackville is next to a wetland, this
provides around 0.5dbi gain (or more)

The conductivity of the ground, not necessarily the wetness will
affect the angle of radiation at low, medium, and HF. It has little if
anything to do with VHF and higher.

0.5 or 1/2 of one dbi (meaning the signal strength is measured as a
ratio as to what can be expected from an isotropic radiator
(imaginary)

A normal dipole has 2.2 dbi of gain. IE a bow tie with no reflector.
That means we are talking negative gain, but a half db would only be
detectable under laboratory, or controlled conditions.

Antenna gain has nothing to do with the type of modulation used.

-- Samara aka Selal-al-Deel (at Balad Air Base) shortwave relay station used
by Iraq until 1990s required 500 kw transmitters to achieve similar reach
with similar antennas

Longwave and wet ground

Short wave and Long wave play by different rules.

-- Iceland's RUV longwave frequency seasonally can reach Gatlinburg, TN in
the USA with audible programming... however, Algeria's Bechar LW site has
only succeeded in propagation carrier waves into North America

The propagation path from near polar regions is quite different than
the path from equatorial regions.

LF and MF are more affected by absorption in the ionosphere than by
ground conductivity. On HF the angle of radiation is some what
affected by soil conditions (depending on the height of the antenna),
but is more affected by refraction in the ionosphere. VHF and UP are
affected more by absorption IN the atmosphere and are only refracted
by the ionosphere (not reflected) under unusual conditions.
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

AM and AM like modulation formats (like 8VSB) are more susceptible to ground
fading than FM like modulation formats.
Some digital modulation formats fall in-between.

The issue is more important for VHF propagation than UHF, but there is some
affect on UHF.

When in doubt look back to the basic laws of physics as to why some
modulation schemes are better in some nations vs others...

How wet ground affects other wavelengths
-- Canada's SW relay station at Sackville is next to a wetland, this
provides around 0.5dbi gain (or more)

The conductivity of the ground, not necessarily the wetness will
affect the angle of radiation at low, medium, and HF. It has little if
anything to do with VHF and higher.

0.5 or 1/2 of one dbi (meaning the signal strength is measured as a
ratio as to what can be expected from an isotropic radiator
(imaginary)

A normal dipole has 2.2 dbi of gain. IE a bow tie with no reflector.
That means we are talking negative gain, but a half db would only be
detectable under laboratory, or controlled conditions.

Antenna gain has nothing to do with the type of modulation used.

-- Samara aka Selal-al-Deel (at Balad Air Base) shortwave relay station
used
by Iraq until 1990s required 500 kw transmitters to achieve similar reach
with similar antennas

Longwave and wet ground

Short wave and Long wave play by different rules.

-- Iceland's RUV longwave frequency seasonally can reach Gatlinburg, TN in
the USA with audible programming... however, Algeria's Bechar LW site has
only succeeded in propagation carrier waves into North America

The propagation path from near polar regions is quite different than
the path from equatorial regions.

LF and MF are more affected by absorption in the ionosphere than by
ground conductivity. On HF the angle of radiation is some what
affected by soil conditions (depending on the height of the antenna),
but is more affected by refraction in the ionosphere. VHF and UP are
affected more by absorption IN the atmosphere and are only refracted
by the ionosphere (not reflected) under unusual conditions.
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com