FM radio receiver in space

Nomen Nescio wrote in message . ..
Psycho Netkook Coward Alan Erskine kooked:

Civilian FM broadcast blah blah blah

Psycho netkook coward Alan Erskine likes to challenge other posters to come
to Melbourne and look him up in the phone book. But he's NOT in the phone
book, he is a COWARD. Besides being a troll, a netkook, a psycho, a
netstalker, etc., etc., etc., that is.

Post your address and phone number, netkook. Otherwise you're the biggest
COWARD of all, psycho.

Bye bye, chicken. Cluck! Cluck, cluck! Cluck, cluck, cluck!

About Alan Erskine

Alan Erskine is a well known Australian netkook, psychopath, and pedophile
who lives in Melbourne. He usually stalks and harasses the posters of the
sci.space groups, although he is known to make excursions into a wide range
of other groups for the purposes of trolling and stalking and harassing the
participants there. He is currently under investigation by the authorities
in Australia. If you fall victim to his frequent attacks and
stalking/harassment campaigns, like so many in the sci.space groups have,
notify . This psycho is dangerous.

Most sane participants have been forced to killfile him for his frequent
violent outbursts at posters and his unrelenting attacks. Some are taking
legal action against him.

Here are just a few of his victims. He has been stalking and harrasing
Scott and Betty Grissom relentlessly. Scott Grissom is the son of Gus
Grissom, the second American in space, who died in an Apolo 1 training
exercise fire, and Betty Grissom, 75, is his widow.

Alan has also been waging long-time stalking and harassment campaigns
against other well-known members of the space community, including Richard
Katz of NASA, John Maxson, and his sons Paul and Daniel Maxson.

Alan is not just content to harass his victims in the newsgroups, he
usually also stalks them via email. If you find yourself on the receiving
end of Alan's famous psychotic emails, contact
immediately, as well as the law enforcement agencies in Melbourne,
Australia. This psycho is very, VERY dangerous. Do not attempt to reason
with him yourself, many others have tried and he does not respond to
reason. Let the authorities deal with him.

hello, is there anyone out there? for the record, alan has
questioned me. he has never attacked me or my mother in any maner,
unlike mosley, hedrick, lowther (failed engineer/failed publisher) and
others. ssh is a full contact sport, and that's fine with me. the
attacks on alan, rk and john need to stop. let's get back to "bidness"
as we say in texas.....we're all fans of manned space flight,
reguardless of our perspective.

You can't pick up FM stations in space. Typical "Twilight Zone"
mentality.


Then how is NA1SS able to talk to schools and such here on the ground? What
about direct comm's between earth stations and satellites?

Jason A. Ciastko
N9ZSY

wrote in message
om...

hello, is there anyone out there?

I am; I've been supporting the Scott Grissom who appeared on
the Mosley-led defamation scene back in the summer of 2001.

http://tinyurl.com/is0x
9/7/2001 - @wt.net

for the record, alan has questioned me. he has never attacked
me or my mother in any maner, unlike mosley, hedrick, lowther
(failed engineer/failed publisher) and others.

Huh? Here's some of the record:

http://tinyurl.com/is1a
4/21/2003 - @wt.net

http://tinyurl.com/is1c
4/22/2003 - @wt.net

ssh is a full contact sport, and that's fine with me.

However, s.s.t. is supposedly *moderated*, by Herbert.

http://tinyurl.com/is12
4/29/2002 - @wt.net

the attacks on alan, rk and john need to stop. let's get back to
"bidness" as we say in texas.....we're all fans of manned space
flight, reguardless of our perspective.

--
John Thomas Maxson, Retired Engineer (Aerospace)
Author, The Betrayal of Mission 51-L (www.mission51l.com)

On Tue, 29 Jul 2003 16:20:32 +0200, "Stanislaw Sidor" wrote:
Newsuser "George J. Molnar" wrote: ...
The receiver, with a proper antenna (not shielded within the vehicle) will
pick up pretty much every station within line-of-sight. At any given moment,
the strongest signal will override the others, owing to the "capture effect"
of FM transmission. However, with rapid movement and constantly varying
geometry, the signals will fluctuate rapidly, bringing one signal, then
another, to the fore.

Notice, that FM radio transmitter and it's antennas are optimized for
horizontal broadcasting (not for transmitting to the space).

At least in the US, all FM broadcast stations use circular polarization.
This allows the vertically polarized whips of car antennas to receive
them efficiently, as well as the horizontally polarized home antennas.
The antenna patterns are aimed toward the horizon, but the patterns
are not all that sharp. Significant energy is still being transmitted at
higher angles (well over half of the total is delivered above the horizon
as a matter of fact).


Diffraction and dissipation absorbs almost all wave's energy and the
ionosphere usually ends the matter, so I'm not sure, that receiving FM radio
from space is so easy.

Class C stations operate with 100,000 watts ERP (Effective Radiated
Power). The ionosphere is essentially transparent to low VHF signals.
(There is some rare E layer refraction, but even that is irrelevant for
signals approaching the ionosphere at angles greater than the critical
angle.) So even the cheapest FM broadcast receivers would have
no problem getting a strong signal in low Earth orbit.

The primary issue is interference, as George noted. There would
be several different signals on the same channels at the same time
in the LEO receiver's line of sight. The strongest signal at any instant
would capture the receiver, but because the LEO receiver is moving,
which station's signal is strongest would change from moment to
moment.

Gary

"John Maxson"
hello, is there anyone out there?

I am;

Did you start a new thread to post this?

(top post)

Perhaps Scott should do a google search for my name. I think you'll find
that, yes, I _did_ attack you and your mum. That was before the
'interogation' period earlier this year.

--
Alan Erskine
alanerskine(at)optusnet.com.au
Is Lewis Moran the type of father figure
John Howard wants for Australian children?

"Kent Betts" wrote in message
om...

for the record, alan has
questioned me. he has never attacked me or my mother

A Erskine
Grissom's a nut and so's his oft-quoted mommy

BTW you quote too much.

"Kent Betts" wrote in message
om...
| "John Maxson"
| hello, is there anyone out there?
|
| I am;
|
| Did you start a new thread to post this?

Ah, but is it really him.....:-)

Peers out from under dustbin lid...

Brian

--
Brian Gaff....
graphics are great, but the blind can't hear them
Email:
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Newsuser "Gary Coffman" wrote: ...

Notice, that FM radio transmitter and it's antennas are optimized for
horizontal broadcasting (not for transmitting to the space).

At least in the US, all FM broadcast stations use circular polarization.
This allows the vertically polarized whips of car antennas to receive
them efficiently, as well as the horizontally polarized home antennas.
The antenna patterns are aimed toward the horizon, but the patterns
are not all that sharp. Significant energy is still being transmitted at
higher angles (well over half of the total is delivered above the horizon
as a matter of fact).

Near the transmitter - it's true, but far, far away, diffraction plays
important main role.
I'm agree that the vertical leak is quite significant.
Not all FM stations use circular polarization. Many of them (not in USA) use
either horizontal either vertical but the geometry of power is still optimized
for horizontal maximization.

The primary issue is interference, as George noted. There would
be several different signals on the same channels at the same time
in the LEO receiver's line of sight. The strongest signal at any instant
would capture the receiver, but because the LEO receiver is moving,
which station's signal is strongest would change from moment to
moment.

... what ends speculations about possibilities of FM clear receiving being in
space.

(STS)

On Thu, 7 Aug 2003 21:16:41 +0200, "Stanislaw Sidor" wrote:
Newsuser "Gary Coffman" wrote: ...
At least in the US, all FM broadcast stations use circular polarization.
This allows the vertically polarized whips of car antennas to receive
them efficiently, as well as the horizontally polarized home antennas.
The antenna patterns are aimed toward the horizon, but the patterns
are not all that sharp. Significant energy is still being transmitted at
higher angles (well over half of the total is delivered above the horizon
as a matter of fact).

Near the transmitter - it's true, but far, far away, diffraction plays
important main role.

Only on Earth's surface. Knife edge diffraction can allow VHF signals
to penetrate into valleys which are not line of sight with the transmitting
antenna. But that's irrelevant for signal energy propagating above the
horizon. There are no obstacles to cause diffraction. (Note that the
antenna patterns used are nowhere near the diffraction limit, a different
issue, and so that's not a consideration.)

I'm agree that the vertical leak is quite significant.

I wouldn't call it a leak. It is an inevitable function of the antenna
pattern. It is impractical at VHF to have a broadcast antenna pattern
with a sharp cutoff. All patterns are "balloon" patterns to one extent
or another. In the US, broadcast antenna gains are on the order of
10 dBi. Most of that gain is achieved by limiting the energy radiating
straight up and straight down, but there is still very significant energy
radiated above the horizon. Essentially all of that finds its way into
outer space.

Not all FM stations use circular polarization. Many of them (not in USA) use
either horizontal either vertical but the geometry of power is still optimized
for horizontal maximization.

The center of the main lobe is typically aimed at the horizon, or about
0.6 degree below the horizon for antennas mounted on 1,000 foot tall
towers. But the half power beamwidth is typically around 22 degrees,
so essentially half the power winds up above the horizon, and finds its
way into outer space. (If we could do much better, we would, because
that power isn't heading toward our target audience and represents
wasted money. But we can't do much better in practice, so we accept
that spill.)

Note that the pattern shape means an orbiting satellite will receive
the strongest signal from a terrestrial FM broadcast station just after
the station comes over the satellite's horizon. When the satellite is
directly overhead, it receives less signal because it is furtherest out
of the pattern lobe center. (That's compensated somewhat by the
satellite being physically closer to the transmitting site, thus reducing
1/r^2 loss, but it typically isn't enough to avoid reduced signal strength
when directly overhead.)

The primary issue is interference, as George noted. There would
be several different signals on the same channels at the same time
in the LEO receiver's line of sight. The strongest signal at any instant
would capture the receiver, but because the LEO receiver is moving,
which station's signal is strongest would change from moment to
moment.

... what ends speculations about possibilities of FM clear receiving being in
space.

Yes, for standard broadcast where the frequencies are reused on a fairly
frequent spatial basis. But it doesn't rule out receiving other FM signals
on other parts of the spectrum which are not frequently spatially reused.

Even some FM broadcast signals would have relatively little interference
at certain points in the satellite's orbit. For example, if the satellite is
approaching the US west coast from over the Pacific, it would only see
signals from those stations inside its range circle on the west coast
(there not being any broadcast stations in the oceans). There are several
which would be effectively clear channel stations given that geometry.
They could easily be received until the satellite progresses further in its
orbit and brings more of the US above its horizon. Similar situations
would exist for stations in Australia, Europe, etc.

Now obviously, there is no way a satellite can receive a single station
during its entire orbit. The signal can only reach the satellite when the
particular station is above its horizon. The only exception to that would
be a geosynchronous orbit. Then the satellite would always have the
same range circle view, and would always see the same stations. But
a geosync orbit would have a range circle view of nearly one third of
the planet, so the interference issue rises to the fore again.

Gary

JRS: In article , seen in
news:sci.space.station, Gary R Coffman posted at
Sun, 10 Aug 2003 19:44:07 :-

The center of the main lobe is typically aimed at the horizon, or about
0.6 degree below the horizon for antennas mounted on 1,000 foot tall
towers.

Do you mean what you write, or should that second "horizon" be
"horizontal"? From a height of 1000 feet, the visible horizon (assuming
level ground) is depressed about 0.56 degrees from the perpendicular-to-
the-vertical.

--
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