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Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff

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  Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff Serg Io <invliad@invalid.com> - 2017-02-12 21:12 -0600
    Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff noTthaTguY <abu.kuanysh05@gmail.com> - 2017-02-12 19:31 -0800
    Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff The Starmaker <starmaker@ix.netcom.com> - 2017-02-13 09:46 -0800
      Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff James McGinn <jimmcginn9@gmail.com> - 2017-02-14 07:32 -0800
      Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff noTthaTguY <abu.kuanysh05@gmail.com> - 2017-02-14 10:19 -0800
    Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff moroney@world.std.spaamtrap.com (Michael Moroney) - 2017-02-13 22:07 +0000
      Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff The Starmaker <starmaker@ix.netcom.com> - 2017-02-13 18:45 -0800
        Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff moroney@world.std.spaamtrap.com (Michael Moroney) - 2017-02-14 12:49 +0000
        Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff James McGinn <jimmcginn9@gmail.com> - 2017-02-14 07:38 -0800
      Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff Poutnik <poutnik4nntp@gmail.com> - 2017-02-14 06:27 +0100
        Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff john <johnsefton288@gmail.com> - 2017-02-14 02:31 -0800
          Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff Serg Io <invliad@invalid.com> - 2017-02-14 07:57 -0600
            Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff john <johnsefton288@gmail.com> - 2017-02-14 07:28 -0800
      Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff Mahipal <mahipal7638@gmail.com> - 2017-02-14 05:23 -0800
        Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff Serg Io <invliad@invalid.com> - 2017-02-14 08:22 -0600
          Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff john <johnsefton288@gmail.com> - 2017-02-14 07:18 -0800
            Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff Serg Io <invliad@invalid.com> - 2017-02-14 09:49 -0600
              Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff James McGinn <jimmcginn9@gmail.com> - 2017-02-14 08:04 -0800
          Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff Mahipal <mahipal7638@gmail.com> - 2017-02-14 07:29 -0800
          Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff James McGinn <jimmcginn9@gmail.com> - 2017-02-14 07:41 -0800
            Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff edprochak@gmail.com - 2017-02-14 11:48 -0800
              Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff James McGinn <jimmcginn9@gmail.com> - 2017-02-15 09:03 -0800
        Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff benj <benj@nobody.net> - 2017-02-14 18:52 -0500
          Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff Mahipal <mahipal7638@gmail.com> - 2017-02-14 21:14 -0800
      Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff James McGinn <jimmcginn9@gmail.com> - 2017-02-14 07:36 -0800
        Re: Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff noTthaTguY <abu.kuanysh05@gmail.com> - 2017-02-14 13:26 -0800
      Michael Moroney can't/won't read me properly. Jeff-Relf.Me <@.> - 2017-02-14 18:18 -0800
        The inmates always hate their description moroney@world.std.spaamtrap.com (Michael Moroney) - 2017-02-15 04:28 +0000

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#618405 — Is sci.physics now 100 % scrap ? and AM transmitter antenna stuff

Is sci.physics now 100 % clutter ?


        any real physics at all being posted ?




At present, FCC restrictions require the use of an antenna with Part 15 
transmitters to be either 10 feet or less, or limit field strength to 
2400 / f in kHz. This applies in the the top of the AM broadcast band 
and certain other frequencies. Consult current FCC rules. However, as 
long as you are using 100 milliwatts and a 10 foot antenna, there is no 
specific limit on range. Typical antenna efficiencies at 1.6 MHz are 
about 0.5 to 1 percent. This limits effective radiated power to 1 
milliwatt or less. This sounds discouraging, but it is not really bad. 
If an antenna radiating 1 milliwatt is placed at the center of a sphere 
of 1 mile in diameter, all this power is still present at the surface, 
less any losses inside the sphere (very small in most cases can be 
considered zero as in free space). The following is a mathematical 
demonstration of this but you can skip it and take our word for it 
should you not care for the details.

The surface area of a 1 km (1000 meters) radius sphere is 4 x pi x r 
squared, where pi = 3.14159 and r squared = 1,000,000

Surface Area = 12.56 x 10 exp 6 (12.56 million square meters)

Dividing 1 milliwatt (1/1000 of a watt) by this figure, we get the power 
per square meter as (79 x 10 exp -12 watts)

The signal in volts per meter can be calculated by realizing that free 
space has an impedance of 377 ohms

The signal strength in volts/meter is equal to the square root of the 
power/sq meter x the impedance in ohms

multiplying power/sq meter by 377 ohms and taking the square root we get 
172.5 microvolts/meter at 1 kM (1000 meters or 0.62 miles)

At 1 mile this would be 107.15 microvolts/meter (uv/meter or uv/m)

Now, 107 uV/meter is a fairly good signal level. As signal levels of 50 
uV/m are still useable a range of over 2 miles should be obtained with a 
properly tuned antenna and 100 milliwatts. A decent AM receiver with a 
ferrite loop antenna can easily pick this up. A good AM receiver with a 
sensitivity of 10 uV per meter might hear this signal at several miles. 
However, ambient noise and interference will be the limiting factor. 
Using similar antennas (8 foot whip with loading coil), Amateur radio 
operators have operated transmitters from automobiles on the nearby (in 
frequency) 160 meter ham band (1800-2000 kHz) and with 10 watts, two way 
contacts of 25 to 50 miles are possible. This would correspond to 2.5 to 
5 miles range with 100 milliwatts. Typical AM receivers equipped with 
the usual ferrite rod or loop antennas have sensitivities ranging from 5 
uV/meter for excellent receivers with large loop antennas, to as poor as 
2000 uV/meter for cheap small AM portable sets. 50 to 300uV / meter is 
typical for average AM BC receivers. This depends on antenna size, 
receiver gain, and bandwidth. Note that this figure includes the loop 
antenna and is not the same as that would be measured at the 50 to 600 
ohm input terminals of the receiver (if so equipped). In this case, in 
order to get usable radiation, the antenna must take as much power from 
the transmitter as possible and radiate it with maximum efficiency. This 
requires a reasonable ground system and an antenna that is properly 
matched to the transmitter. A 10 foot vertical or whip antenna has an 
impedance of about 3000 ohms capacitive reactance in series with about 
0.1 ohm radiation resistance. The trick is to get as much current 
flowing in this 0.1 ohm resistance as possible. For 1 milliwatt radiated 
power this would be 100 milliamperes (0.1 ampere). To force this much 
current through the impedance of the antenna, an RF level of 300 volts 
is needed. This can be done by using a series inductance to cancel out 
the capacitive reactance of the antenna. A simple indoor 3 foot whip 
plugged into the transmitter, with no matching network, would look like 
about 0.007 ohm in series with 8000 ohms capacitive reactance. About 
3000 volts of RF signal would be needed to have this antenna radiate 1 
milliwatt. Since 100 milliwatts. A 100 milliwatt transmitter would 
supply about 2.3 volts of RF into 50 ohms. Open circuit or the level 
delivered into this antenna would be around 4.5 volts. The radiated 
power would be around 2 nanowatts. This would produce a very weak signal 
barely detectable at more than a few feet from the transmitter.

These high RF voltages appear on the antenna as a result of using a 
loading coil to get a series resonant circuit together with the self 
capacitance of the antenna. This capacitance depends on the antenna 
dimensions and will be around 30 pf for a 10 foot vertical, depending on 
its configuration and diameter. This capacitance can be calculated from 
electromagnetic theory or inferred from an antenna analysis program such 
as ELNEC. For frequencies in the 1.6 MHz region, around 350 to 400 uHy 
will be needed. At 530 kHz around 3000 uHy will be needed.

This inductance can be reduced by using a "capacity hat" on the top of 
the antenna. This is made up of 4 or 6 lengths of wire (12 inches) 
arranged horizontally like the spokes of a wheel, with one end connected 
to the top of the antenna (see fig). The calculated capacitance of this 
short vertical antenna is 36.3 pF and is fairly constant over the entire 
AM broadcast band. This allows a coil of 220 to 2400 microhenries to 
make this antenna resonant from 1700 to 530 kHz. The exact inductance 
will be affected by antenna location, height above ground, length of 
ground lead and size of ground plane, proximity to other objects, and 
other environmental factors. Therefore it is best to start off with a 
coil of somewhat higher inductance than actually needed, and adjust the 
number of turns experimentally. Best radiation efficiency is at the 
higher frequencies.

[toc] | [next] | [standalone]

#618407

three, what?

> This inductance can be reduced by using a "capacity hat" on the top of 
> the antenna. This is made up of 4 or 6 lengths of wire (12 inches) 
> arranged horizontally like the spokes of a wheel, with one end connected 
> to the top of the antenna (see fig). The calculated capacitance of this 
> short vertical antenna is 36.3 pF and is fairly constant over the entire 
> AM broadcast band. This allows a coil of 220 to 2400 microhenries to 
> make this antenna resonant from 1700 to 530 kHz. The exact inductance 
> will be affected by antenna location, height above ground, length of 
> ground lead and size of ground plane, proximity to other objects, and 
> other environmental factors. Therefore it is best to start off with a 
> coil of somewhat higher inductance than actually needed, and adjust the 
> number of turns experimentally. Best radiation efficiency is at the 
> higher frequencies.

[toc] | [prev] | [next] | [standalone]

#618445

Well, you are just doing what you always have done and the rest of the 'scientific community' does, Cut-and-Paste Science.
http://www.northcountryradio.com/Articles/Construction%20of%20AM88%20Antenna.htm

I suspect most homework turned in class today is Cut-and-Paste Science.


Then they graduate with Cut-and-Paste Science Thinking.


and you're part of the 100%...














Serg Io wrote:
> 
> Is sci.physics now 100 % clutter ?
> 
>         any real physics at all being posted ?
> 
> At present, FCC restrictions require the use of an antenna with Part 15
> transmitters to be either 10 feet or less, or limit field strength to
> 2400 / f in kHz. This applies in the the top of the AM broadcast band
> and certain other frequencies. Consult current FCC rules. However, as
> long as you are using 100 milliwatts and a 10 foot antenna, there is no
> specific limit on range. Typical antenna efficiencies at 1.6 MHz are
> about 0.5 to 1 percent. This limits effective radiated power to 1
> milliwatt or less. This sounds discouraging, but it is not really bad.
> If an antenna radiating 1 milliwatt is placed at the center of a sphere
> of 1 mile in diameter, all this power is still present at the surface,
> less any losses inside the sphere (very small in most cases can be
> considered zero as in free space). The following is a mathematical
> demonstration of this but you can skip it and take our word for it
> should you not care for the details.
> 
> The surface area of a 1 km (1000 meters) radius sphere is 4 x pi x r
> squared, where pi = 3.14159 and r squared = 1,000,000
> 
> Surface Area = 12.56 x 10 exp 6 (12.56 million square meters)
> 
> Dividing 1 milliwatt (1/1000 of a watt) by this figure, we get the power
> per square meter as (79 x 10 exp -12 watts)
> 
> The signal in volts per meter can be calculated by realizing that free
> space has an impedance of 377 ohms
> 
> The signal strength in volts/meter is equal to the square root of the
> power/sq meter x the impedance in ohms
> 
> multiplying power/sq meter by 377 ohms and taking the square root we get
> 172.5 microvolts/meter at 1 kM (1000 meters or 0.62 miles)
> 
> At 1 mile this would be 107.15 microvolts/meter (uv/meter or uv/m)
> 
> Now, 107 uV/meter is a fairly good signal level. As signal levels of 50
> uV/m are still useable a range of over 2 miles should be obtained with a
> properly tuned antenna and 100 milliwatts. A decent AM receiver with a
> ferrite loop antenna can easily pick this up. A good AM receiver with a
> sensitivity of 10 uV per meter might hear this signal at several miles.
> However, ambient noise and interference will be the limiting factor.
> Using similar antennas (8 foot whip with loading coil), Amateur radio
> operators have operated transmitters from automobiles on the nearby (in
> frequency) 160 meter ham band (1800-2000 kHz) and with 10 watts, two way
> contacts of 25 to 50 miles are possible. This would correspond to 2.5 to
> 5 miles range with 100 milliwatts. Typical AM receivers equipped with
> the usual ferrite rod or loop antennas have sensitivities ranging from 5
> uV/meter for excellent receivers with large loop antennas, to as poor as
> 2000 uV/meter for cheap small AM portable sets. 50 to 300uV / meter is
> typical for average AM BC receivers. This depends on antenna size,
> receiver gain, and bandwidth. Note that this figure includes the loop
> antenna and is not the same as that would be measured at the 50 to 600
> ohm input terminals of the receiver (if so equipped). In this case, in
> order to get usable radiation, the antenna must take as much power from
> the transmitter as possible and radiate it with maximum efficiency. This
> requires a reasonable ground system and an antenna that is properly
> matched to the transmitter. A 10 foot vertical or whip antenna has an
> impedance of about 3000 ohms capacitive reactance in series with about
> 0.1 ohm radiation resistance. The trick is to get as much current
> flowing in this 0.1 ohm resistance as possible. For 1 milliwatt radiated
> power this would be 100 milliamperes (0.1 ampere). To force this much
> current through the impedance of the antenna, an RF level of 300 volts
> is needed. This can be done by using a series inductance to cancel out
> the capacitive reactance of the antenna. A simple indoor 3 foot whip
> plugged into the transmitter, with no matching network, would look like
> about 0.007 ohm in series with 8000 ohms capacitive reactance. About
> 3000 volts of RF signal would be needed to have this antenna radiate 1
> milliwatt. Since 100 milliwatts. A 100 milliwatt transmitter would
> supply about 2.3 volts of RF into 50 ohms. Open circuit or the level
> delivered into this antenna would be around 4.5 volts. The radiated
> power would be around 2 nanowatts. This would produce a very weak signal
> barely detectable at more than a few feet from the transmitter.
> 
> These high RF voltages appear on the antenna as a result of using a
> loading coil to get a series resonant circuit together with the self
> capacitance of the antenna. This capacitance depends on the antenna
> dimensions and will be around 30 pf for a 10 foot vertical, depending on
> its configuration and diameter. This capacitance can be calculated from
> electromagnetic theory or inferred from an antenna analysis program such
> as ELNEC. For frequencies in the 1.6 MHz region, around 350 to 400 uHy
> will be needed. At 530 kHz around 3000 uHy will be needed.
> 
> This inductance can be reduced by using a "capacity hat" on the top of
> the antenna. This is made up of 4 or 6 lengths of wire (12 inches)
> arranged horizontally like the spokes of a wheel, with one end connected
> to the top of the antenna (see fig). The calculated capacitance of this
> short vertical antenna is 36.3 pF and is fairly constant over the entire
> AM broadcast band. This allows a coil of 220 to 2400 microhenries to
> make this antenna resonant from 1700 to 530 kHz. The exact inductance
> will be affected by antenna location, height above ground, length of
> ground lead and size of ground plane, proximity to other objects, and
> other environmental factors. Therefore it is best to start off with a
> coil of somewhat higher inductance than actually needed, and adjust the
> number of turns experimentally. Best radiation efficiency is at the
> higher frequencies.

[toc] | [prev] | [next] | [standalone]

#618581

On Monday, February 13, 2017 at 9:46:37 AM UTC-8, The Starmaker wrote:
> Well, you are just doing what you always have done and the rest of the 'scientific community' does, Cut-and-Paste Science.
> http://www.northcountryradio.com/Articles/Construction%20of%20AM88%20Antenna.htm
> 
> I suspect most homework turned in class today is Cut-and-Paste Science.
> 
> 
> Then they graduate with Cut-and-Paste Science Thinking.
> 
> 
> and you're part of the 100%...
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Serg Io wrote:
> > 
> > Is sci.physics now 100 % clutter ?
> > 
> >         any real physics at all being posted ?
> > 
> > At present, FCC restrictions require the use of an antenna with Part 15
> > transmitters to be either 10 feet or less, or limit field strength to
> > 2400 / f in kHz. This applies in the the top of the AM broadcast band
> > and certain other frequencies. Consult current FCC rules. However, as
> > long as you are using 100 milliwatts and a 10 foot antenna, there is no
> > specific limit on range. Typical antenna efficiencies at 1.6 MHz are
> > about 0.5 to 1 percent. This limits effective radiated power to 1
> > milliwatt or less. This sounds discouraging, but it is not really bad.
> > If an antenna radiating 1 milliwatt is placed at the center of a sphere
> > of 1 mile in diameter, all this power is still present at the surface,
> > less any losses inside the sphere (very small in most cases can be
> > considered zero as in free space). The following is a mathematical
> > demonstration of this but you can skip it and take our word for it
> > should you not care for the details.
> > 
> > The surface area of a 1 km (1000 meters) radius sphere is 4 x pi x r
> > squared, where pi = 3.14159 and r squared = 1,000,000
> > 
> > Surface Area = 12.56 x 10 exp 6 (12.56 million square meters)
> > 
> > Dividing 1 milliwatt (1/1000 of a watt) by this figure, we get the power
> > per square meter as (79 x 10 exp -12 watts)
> > 
> > The signal in volts per meter can be calculated by realizing that free
> > space has an impedance of 377 ohms
> > 
> > The signal strength in volts/meter is equal to the square root of the
> > power/sq meter x the impedance in ohms
> > 
> > multiplying power/sq meter by 377 ohms and taking the square root we get
> > 172.5 microvolts/meter at 1 kM (1000 meters or 0.62 miles)
> > 
> > At 1 mile this would be 107.15 microvolts/meter (uv/meter or uv/m)
> > 
> > Now, 107 uV/meter is a fairly good signal level. As signal levels of 50
> > uV/m are still useable a range of over 2 miles should be obtained with a
> > properly tuned antenna and 100 milliwatts. A decent AM receiver with a
> > ferrite loop antenna can easily pick this up. A good AM receiver with a
> > sensitivity of 10 uV per meter might hear this signal at several miles.
> > However, ambient noise and interference will be the limiting factor.
> > Using similar antennas (8 foot whip with loading coil), Amateur radio
> > operators have operated transmitters from automobiles on the nearby (in
> > frequency) 160 meter ham band (1800-2000 kHz) and with 10 watts, two way
> > contacts of 25 to 50 miles are possible. This would correspond to 2.5 to
> > 5 miles range with 100 milliwatts. Typical AM receivers equipped with
> > the usual ferrite rod or loop antennas have sensitivities ranging from 5
> > uV/meter for excellent receivers with large loop antennas, to as poor as
> > 2000 uV/meter for cheap small AM portable sets. 50 to 300uV / meter is
> > typical for average AM BC receivers. This depends on antenna size,
> > receiver gain, and bandwidth. Note that this figure includes the loop
> > antenna and is not the same as that would be measured at the 50 to 600
> > ohm input terminals of the receiver (if so equipped). In this case, in
> > order to get usable radiation, the antenna must take as much power from
> > the transmitter as possible and radiate it with maximum efficiency. This
> > requires a reasonable ground system and an antenna that is properly
> > matched to the transmitter. A 10 foot vertical or whip antenna has an
> > impedance of about 3000 ohms capacitive reactance in series with about
> > 0.1 ohm radiation resistance. The trick is to get as much current
> > flowing in this 0.1 ohm resistance as possible. For 1 milliwatt radiated
> > power this would be 100 milliamperes (0.1 ampere). To force this much
> > current through the impedance of the antenna, an RF level of 300 volts
> > is needed. This can be done by using a series inductance to cancel out
> > the capacitive reactance of the antenna. A simple indoor 3 foot whip
> > plugged into the transmitter, with no matching network, would look like
> > about 0.007 ohm in series with 8000 ohms capacitive reactance. About
> > 3000 volts of RF signal would be needed to have this antenna radiate 1
> > milliwatt. Since 100 milliwatts. A 100 milliwatt transmitter would
> > supply about 2.3 volts of RF into 50 ohms. Open circuit or the level
> > delivered into this antenna would be around 4.5 volts. The radiated
> > power would be around 2 nanowatts. This would produce a very weak signal
> > barely detectable at more than a few feet from the transmitter.
> > 
> > These high RF voltages appear on the antenna as a result of using a
> > loading coil to get a series resonant circuit together with the self
> > capacitance of the antenna. This capacitance depends on the antenna
> > dimensions and will be around 30 pf for a 10 foot vertical, depending on
> > its configuration and diameter. This capacitance can be calculated from
> > electromagnetic theory or inferred from an antenna analysis program such
> > as ELNEC. For frequencies in the 1.6 MHz region, around 350 to 400 uHy
> > will be needed. At 530 kHz around 3000 uHy will be needed.
> > 
> > This inductance can be reduced by using a "capacity hat" on the top of
> > the antenna. This is made up of 4 or 6 lengths of wire (12 inches)
> > arranged horizontally like the spokes of a wheel, with one end connected
> > to the top of the antenna (see fig). The calculated capacitance of this
> > short vertical antenna is 36.3 pF and is fairly constant over the entire
> > AM broadcast band. This allows a coil of 220 to 2400 microhenries to
> > make this antenna resonant from 1700 to 530 kHz. The exact inductance
> > will be affected by antenna location, height above ground, length of
> > ground lead and size of ground plane, proximity to other objects, and
> > other environmental factors. Therefore it is best to start off with a
> > coil of somewhat higher inductance than actually needed, and adjust the
> > number of turns experimentally. Best radiation efficiency is at the
> > higher frequencies.

Cut and paste is all this retard knows.

[toc] | [prev] | [next] | [standalone]

#618621

ah, g00d; see that the secondpower of the speed of light is

> > milliwatt or less. This sounds discouraging, but it is not really bad.
> > If an antenna radiating 1 milliwatt is placed at the center of a sphere
> > of 1 mile in diameter, all this power is still present at the surface,
> > less any losses inside the sphere (very small in most cases can be
> > considered zero as in free space). The following is a mathematical
> > demonstration of this but you can skip it and take our word for it
> > should you not care for the details.
> > 
> > The surface area of a 1 km (1000 meters) radius sphere is 4 x pi x r
> > squared, where pi = 3.14159 and r squared = 1,000,000
> > 
> > Surface Area = 12.56 x 10 exp 6 (12.56 million square meters)
> > 
> > Dividing 1 milliwatt (1/1000 of a watt) by this figure, we get the power
> > per square meter as (79 x 10 exp -12 watts)
> > 
> > The signal in volts per meter can be calculated by realizing that free
> > space has an impedance of 377 ohms
> > 
> > The signal strength in volts/meter is equal to the square root of the
> > power/sq meter x the impedance in ohms
> > 
> > multiplying power/sq meter by 377 ohms and taking the square root we get
> > 172.5 microvolts/meter at 1 kM (1000 meters or 0.62 miles)
> > 
> > At 1 mile this would be 107.15 microvolts/meter (uv/meter or uv/m)
> > 
> > Now, 107 uV/meter is a fairly good signal level. As signal levels of 50
> > uV/m are still useable a range of over 2 miles should be obtained with a
> > properly tuned antenna and 100 milliwatts. A decent AM receiver with a
> > ferrite loop antenna can easily pick this up. A good AM receiver with a
> > sensitivity of 10 uV per meter might hear this signal at several miles.
> > However, ambient noise and interference will be the limiting factor.
> > Using similar antennas (8 foot whip with loading coil), Amateur radio
> > operators have operated transmitters from automobiles on the nearby (in
> > frequency) 160 meter ham band (1800-2000 kHz) and with 10 watts, two way
> > contacts of 25 to 50 miles are possible. This would correspond to 2.5 to
> > 5 miles range with 100 milliwatts. Typical AM receivers equipped with
> > the usual ferrite rod or loop antennas have sensitivities ranging from 5
> > uV/meter for excellent receivers with large loop antennas, to as poor as
> > 2000 uV/meter for cheap small AM portable sets. 50 to 300uV / meter is
> > typical for average AM BC receivers. This depends on antenna size,
> > receiver gain, and bandwidth. Note that this figure includes the loop
> > antenna and is not the same as that would be measured at the 50 to 600
> > ohm input terminals of the receiver (if so equipped). In this case, in
> > order to get usable radiation, the antenna must take as much power from
> > the transmitter as possible and radiate it with maximum efficiency. This
> > requires a reasonable ground system and an antenna that is properly
> > matched to the transmitter. A 10 foot vertical or whip antenna has an
> > impedance of about 3000 ohms capacitive reactance in series with about
> > 0.1 ohm radiation resistance. The trick is to get as much current
> > flowing in this 0.1 ohm resistance as possible. For 1 milliwatt radiated
> > power this would be 100 milliamperes (0.1 ampere). To force this much
> > current through the impedance of the antenna, an RF level of 300 volts
> > is needed. This can be done by using a series inductance to cancel out
> > the capacitive reactance of the antenna. A simple indoor 3 foot whip
> > plugged into the transmitter, with no matching network, would look like
> > about 0.007 ohm in series with 8000 ohms capacitive reactance. About
> > 3000 volts of RF signal would be needed to have this antenna radiate 1
> > milliwatt. Since 100 milliwatts. A 100 milliwatt transmitter would
> > supply about 2.3 volts of RF into 50 ohms. Open circuit or the level
> > delivered into this antenna would be around 4.5 volts. The radiated
> > power would be around 2 nanowatts. This would produce a very weak signal
> > barely detectable at more than a few feet from the transmitter.
> > 
> > These high RF voltages appear on the antenna as a result of using a
> > loading coil to get a series resonant circuit together with the self
> > capacitance of the antenna. This capacitance depends on the antenna
> > dimensions and will be around 30 pf for a 10 foot vertical, depending on
> > its configuration and diameter. This capacitance can be calculated from
> > electromagnetic theory or inferred from an antenna analysis program such
> > as ELNEC. For frequencies in the 1.6 MHz region, around 350 to 400 uHy
> > will be needed. At 530 kHz around 3000 uHy will be needed.
> > 
> > This inductance can be reduced by using a "capacity hat" on the top of
> > the antenna. This is made up of 4 or 6 lengths of wire (12 inches)
> > arranged horizontally like the spokes of a wheel, with one end connected
> > to the top of the antenna (see fig). The calculated capacitance of this
> > short vertical antenna is 36.3 pF and is fairly constant over the entire
> > AM broadcast band. This allows a coil of 220 to 2400 microhenries to
> > make this antenna resonant from 1700 to 530 kHz. The exact inductance
> > will be affected by antenna location, height above ground, length of
> > ground lead and size of ground plane, proximity to other objects, and
> > other environmental factors. Therefore it is best to start off with a
> > coil of somewhat higher inductance than actually needed, and adjust the
> > number of turns experimentally. Best radiation efficiency is at the
> > higher frequencies.

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#618487

Serg Io <invliad@invalid.com> writes:

>Is sci.physics now 100 % clutter ?


>        any real physics at all being posted ?

Thanks for trying to inject some actual science here, but to answer your
question, yes, sci.physics is now just a looney bin.

In the first rubber room is this tornado guy who thinks water doesn't
evaporate, then in the next cell there is the really bad programmer who
thinks there is no randomness, then there's the guy who thinks the
universe is a giant atom, next door is the guy fascinated with precessing
spinny things, then in the next cell's occupant thinks the moon makes
water, then a few rubber rooms of babblers, then the cell with the guy
obsessed with one of the babblers, a couple of believers in ghosts and ESP
and last but certainly not least, an entire ward full of those who just
know that Einstein is wrong and each has his very own theory to replace
Einstein's relativity.

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#618528

Michael Moroney wrote:
> 
> Serg Io <invliad@invalid.com> writes:
> 
> >Is sci.physics now 100 % clutter ?
> 
> >        any real physics at all being posted ?
> 
> Thanks for trying to inject some actual science here, but to answer your
> question, yes, sci.physics is now just a looney bin.
> 
> In the first rubber room is this tornado guy who thinks water doesn't
> evaporate, then in the next cell there is the really bad programmer who
> thinks there is no randomness, then there's the guy who thinks the
> universe is a giant atom, next door is the guy fascinated with precessing
> spinny things, then in the next cell's occupant thinks the moon makes
> water, then a few rubber rooms of babblers, then the cell with the guy
> obsessed with one of the babblers, a couple of believers in ghosts and ESP
> and last but certainly not least, an entire ward full of those who just
> know that Einstein is wrong and each has his very own theory to replace
> Einstein's relativity.


What name will you give those who pretend to know everything or pretend
to have the answers for everything????

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#618571

The Starmaker <starmaker@ix.netcom.com> writes:

>What name will you give those who pretend to know everything or pretend
>to have the answers for everything????

"The Starmaker".

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#618583

On Monday, February 13, 2017 at 6:44:23 PM UTC-8, The Starmaker wrote:
> Michael Moroney wrote:
> > 
> > Serg Io <invliad@invalid.com> writes:
> > 
> > >Is sci.physics now 100 % clutter ?
> > 
> > >        any real physics at all being posted ?
> > 
> > Thanks for trying to inject some actual science here, but to answer your
> > question, yes, sci.physics is now just a looney bin.
> > 
> > In the first rubber room is this tornado guy who thinks water doesn't
> > evaporate, then in the next cell there is the really bad programmer who
> > thinks there is no randomness, then there's the guy who thinks the
> > universe is a giant atom, next door is the guy fascinated with precessing
> > spinny things, then in the next cell's occupant thinks the moon makes
> > water, then a few rubber rooms of babblers, then the cell with the guy
> > obsessed with one of the babblers, a couple of believers in ghosts and ESP
> > and last but certainly not least, an entire ward full of those who just
> > know that Einstein is wrong and each has his very own theory to replace
> > Einstein's relativity.
> 
> 
> What name will you give those who pretend to know everything or pretend
> to have the answers for everything????

I call them church ladies.  They alway pretend to have all the ansewers but they are too slow-witted to actually make an argument.

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#618545

Dne 13/02/2017 v 23:07 Michael Moroney napsal(a):
> Serg Io <invliad@invalid.com> writes:
> 
>> Is sci.physics now 100 % clutter ?
> 
> 
>>        any real physics at all being posted ?
> 
> Thanks for trying to inject some actual science here, but to answer your
> question, yes, sci.physics is now just a looney bin.
> 
> In the first rubber room is this tornado guy who thinks water doesn't
> evaporate, then in the next cell there is the really bad programmer who
> thinks there is no randomness, then there's the guy who thinks the
> universe is a giant atom, next door is the guy fascinated with precessing
> spinny things, then in the next cell's occupant thinks the moon makes
> water, then a few rubber rooms of babblers, then the cell with the guy
> obsessed with one of the babblers, a couple of believers in ghosts and ESP
> and last but certainly not least, an entire ward full of those who just
> know that Einstein is wrong and each has his very own theory to replace
> Einstein's relativity.
> 
 nice :-)

-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.

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#618566

Star
"- show quoted text -
What name will you give those who pretend to know everything or pretend 
to have the answers for everything???? "
Blind sheep

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#618573

On 2/14/2017 4:31 AM, john wrote:
> Star
> "- show quoted text -
> What name will you give those who pretend to know everything or pretend
> to have the answers for everything???? "
> Blind sheep
>


Ha! hey Mr  Sheep, arn't you the => "...next door is the guy fascinated 
with precessing spinny things."

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#618579

8.SirSer 
- hide quoted text -
On 2/14/2017 4:31 AM, john wrote: 
> Star 
> "- show quoted text - 
> What name will you give those who pretend to know everything or pretend 
> to have the answers for everything???? " 
> Blind sheep 
> 


"Ha! hey Mr  Sheep, arn't you the => "...next door is the guy fascinated 
with precessing spinny things." "

Sorry. I write English in far too relaxed a manner, sometimes.
"Blind Sheep" are the "non-kooks" who know it
all, and it's right, and what they don't know is
in such-and-such book, and it's right. Like Odd.

I should have written an entire sentence, there:
'The name you give them will be' Blind Sheep.

Sorry.

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#618572

On Monday, February 13, 2017 at 5:07:19 PM UTC-5, Michael Moroney wrote:
> Serg Io <invliad@invalid.com> writes:

Holding a consistent userID handle could serve to improve content quality.

> >Is sci.physics now 100 % clutter ?
> 
> >        any real physics at all being posted ?

Physics is complicated, not a rehashTag@# of contents in its textbooks.

> Thanks for trying to inject some actual science here, but to answer your
> question, yes, sci.physics is now just a looney bin.

If by now is meant since 1990s, then the looney has just grown, as of late.
Used to be a time, a large number of posters here had *.edu domain named
email addresses. I've not seen one here, since I returned to Usenet,
like six years ago. Must have something to do with new universities' policies.

> In the first rubber room is this tornado guy who thinks water doesn't
> evaporate, then in the next cell there is the really bad programmer who
> thinks there is no randomness, then there's the guy who thinks the
> universe is a giant atom, next door is the guy fascinated with precessing
> spinny things, then in the next cell's occupant thinks the moon makes
> water, then a few rubber rooms of babblers, then the cell with the guy
> obsessed with one of the babblers, a couple of believers in ghosts and ESP
> and last but certainly not least, an entire ward full of those who just
> know that Einstein is wrong and each has his very own theory to replace
> Einstein's relativity.

Many here, there, or anywhere... are not just going to simply worship OneStone.

-- Mahipal “IPMM... माहिपाल ७६३८: d(me) != 0 ... me alwa(y)s changes...”

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#618574

On 2/14/2017 7:23 AM, Mahipal wrote:
> On Monday, February 13, 2017 at 5:07:19 PM UTC-5, Michael Moroney wrote:
>> Serg Io <invliad@invalid.com> writes:
>
> Holding a consistent userID handle could serve to improve content quality.

totally agree,
	the "Denk vs. McGinn" discussions
	keep out sellers of wasteland, not even useful for neclear dumps.

>
>>> Is sci.physics now 100 % clutter ?
>>
>>>        any real physics at all being posted ?
>
> Physics is complicated, not a rehashTag@# of contents in its textbooks.

there is a lot of knowledge in sci.physics, I learned from sci.physics 
that one can buy/use high viscosity silicone differential fluid for 
model RC racing on Photomulitplier tubes to scintillator connections.

Books do not have the practical working side of physics, where this 
group can really contribute.

>
>> Thanks for trying to inject some actual science here, but to answer your
>> question, yes, sci.physics is now just a looney bin.
>
> If by now is meant since 1990s, then the looney has just grown, as of late.
> Used to be a time, a large number of posters here had *.edu domain named
> email addresses. I've not seen one here, since I returned to Usenet,
> like six years ago. Must have something to do with new universities' policies.

Microsoft/google has slowly and sucessfully strangled off access to the 
usenet via its browsers, so a person that just bought a computer has no 
idea the usenet exists.  There are some sites that re-broadcast the 
forums, like drexial and others.  So most of the users are older ones 
that know how, or still can connect to usenet, and the younger ones 
prefer to go to the sites with pictures, videos, active content, not 
text, etc.



>
> Many here, there, or anywhere... are not just going to simply worship OneStone.

supporting ideas or beliefs is needed to re-inforce self esteem, even 
oddball ones.

somehow sci.physics posters have arrived here, prescreened by past 
knowledge (older age), and perhaps by no forum in which they would get 
a responce.


>
> -- Mahipal “IPMM... माहिपाल ७६३८: d(me) != 0 ... me alwa(y)s changes...”
>

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#618577

Questioning physics is taboo.
But physics is FULL of open questions.
So, wtf?

Plus- if you can't use your own name-
there's something wrong with you, or your
situation. Maybe go fix that, first.

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#618586

On 2/14/2017 9:18 AM, john wrote:

>
> Plus- if you can't use your own name-
> there's something wrong with you, or your
> situation. Maybe go fix that, first.
>

that idea was pushed by Facebook, to try to get real names, real 
information on its users, so that it can sell high value personal 
information to 3rd parties.  There is no way Facebook can guarentee 
safety of your personal infomation.  Even you can get access to 
Facebooks database and search for a fee.

One of those 3rd parties is the NSA which has a contract with Facebook 
to share information. (NSA guided Facebook R&D) (google and yahoo too)

Also Obama passed a bill 2 days before he was retired as president, that 
all files of the NSA will be shared with the FBI and CIA. (that was not 
in the news much!) Then it can be leaked, by a Snowden, or a lost 
laptop, or... government when they want to...

Before Facebook, most everyone used a fake name on the internet to help 
protect their personal information.

Even if you give Facebook a fake name, they  piece together information 
and recover your address, IP vs address. that is a fact, done for making 
$ by advertizing.

If I have your real name, I can find your house, your land line phone 
number, your relitives and in laws without having to pay any site 
anything.    It is a shameful situation.

the other fact is that what you post stays their forever.  Google keeps 
all your serches forever.  Also it can go away in an instant when the 
site goes belly up.  Or your information can be stripped off and sold 
without protection in a forclosure sale, like HotMail.

there are about 30 internet companies that specalize in collecting 
personal information, and selling their services and information to 3rd 
parties.

     Why help them make money ?

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#618588

On Tuesday, February 14, 2017 at 7:49:48 AM UTC-8, Serg Io wrote:
> On 2/14/2017 9:18 AM, john wrote:
> 
> >
> > Plus- if you can't use your own name-
> > there's something wrong with you, or your
> > situation. Maybe go fix that, first.
> >
> 
> that idea was pushed by Facebook, to try to get real names, real 
> information on its users, so that it can sell high value personal 
> information to 3rd parties.  There is no way Facebook can guarentee 
> safety of your personal infomation.  Even you can get access to 
> Facebooks database and search for a fee.
> 
> One of those 3rd parties is the NSA which has a contract with Facebook 
> to share information. (NSA guided Facebook R&D) (google and yahoo too)
> 
> Also Obama passed a bill 2 days before he was retired as president, that 
> all files of the NSA will be shared with the FBI and CIA. (that was not 
> in the news much!) Then it can be leaked, by a Snowden, or a lost 
> laptop, or... government when they want to...
> 
> Before Facebook, most everyone used a fake name on the internet to help 
> protect their personal information.
> 
> Even if you give Facebook a fake name, they  piece together information 
> and recover your address, IP vs address. that is a fact, done for making 
> $ by advertizing.
> 
> If I have your real name, I can find your house, your land line phone 
> number, your relitives and in laws without having to pay any site 
> anything.    It is a shameful situation.
> 
> the other fact is that what you post stays their forever.  Google keeps 
> all your serches forever.  Also it can go away in an instant when the 
> site goes belly up.  Or your information can be stripped off and sold 
> without protection in a forclosure sale, like HotMail.
> 
> there are about 30 internet companies that specalize in collecting 
> personal information, and selling their services and information to 3rd 
> parties.
> 
>      Why help them make money ?

Wow, sergio knows something.  

I can't figure out why science illiterates hang out in sci.physics

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#618580

On Tuesday, February 14, 2017 at 9:22:56 AM UTC-5, Serg Io wrote:
> On 2/14/2017 7:23 AM, Mahipal wrote:
> > On Monday, February 13, 2017 at 5:07:19 PM UTC-5, Michael Moroney wrote:
> >> Serg Io <invliad@invalid.com> writes:
> >
> > Holding a consistent userID handle could serve to improve content quality.
> 
> totally agree,
> 	the "Denk vs. McGinn" discussions
> 	keep out sellers of wasteland, not even useful for neclear dumps.

I just ignore those posts. Afterall, Usenet is like a bar, everyone is
welcome to drink. Doesn't mean I have to talk to you, or you with me.
Hey, I used to be married, I know all about being ignored. Norm! Cheers.

> >>> Is sci.physics now 100 % clutter ?
> >>
> >>>        any real physics at all being posted ?
> >
> > Physics is complicated, not a rehashTag@# of contents in its textbooks.
> 
> there is a lot of knowledge in sci.physics, I learned from sci.physics 
> that one can buy/use high viscosity silicone differential fluid for 
> model RC racing on Photomulitplier tubes to scintillator connections.

Cute and very specific! Me, I'm more a contemplative philosophical generalist type.

> Books do not have the practical working side of physics, where this 
> group can really contribute.

Yes, we are here to discuss what we've learned through our life's experiences.

> >> Thanks for trying to inject some actual science here, but to answer your
> >> question, yes, sci.physics is now just a looney bin.
> >
> > If by now is meant since 1990s, then the looney has just grown, as of late.
> > Used to be a time, a large number of posters here had *.edu domain named
> > email addresses. I've not seen one here, since I returned to Usenet,
> > like six years ago. Must have something to do with new universities' policies.
> 
> Microsoft/google has slowly and sucessfully strangled off access to the 
> usenet via its browsers, so a person that just bought a computer has no 
> idea the usenet exists.  There are some sites that re-broadcast the 
> forums, like drexial and others.  So most of the users are older ones 
> that know how, or still can connect to usenet, and the younger ones 
> prefer to go to the sites with pictures, videos, active content, not 
> text, etc.

There exists a corporate sponsored conspiracy to kill Usenet. Not that
there exist any conspiracies at all. No, none at all! I was misquoted...

Neither Facebook nor Twitter are a journalistic news medium. At best,
friends and families link to articles found in the digital press.
Nobody takes a selfie of themselves with today's paper newspaper and
posts it to the Internet/WWW/IPMM/... due to too much self-respect.

> > Many here, there, or anywhere... are not just going to simply worship OneStone.
> 
> supporting ideas or beliefs is needed to re-inforce self esteem, even 
> oddball ones.

We all like to find friends who share and get our jokes and thoughts.

> somehow sci.physics posters have arrived here, prescreened by past 
> knowledge (older age), and perhaps by no forum in which they would get 
> a responce.

Only on Usenet, you do not get to block strangers at first sight.
Half the jokes I try convey here, I would never tell on Facebook. Why?
Simple, my MomJi and DadJi would be the first ones to react to it.
Recently, Facebook asked me if I knew my son. I just had to laugh.

LinkedIn claims that I am connected to like two billion people. Really?

Facebook and LinkedIn sites are always telling me of lists of people I
may know. Seriously?! If I knew them, do I need you ITFP?! O(y)e...STFU.

Lesson: I know them alright. I JUST DON'T WANT ANYTHING TO DO WITH THEM!

But Noooo...ooo! FB and LinkedIn need to remind me of them, always. WTF?!

-- Mahipal “IPMM... माहिपाल ७६३८: d(me) != 0 ... me alwa(y)s changes...”

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#618584

On Tuesday, February 14, 2017 at 6:22:56 AM UTC-8, Serg Io wrote:
> On 2/14/2017 7:23 AM, Mahipal wrote:
> > On Monday, February 13, 2017 at 5:07:19 PM UTC-5, Michael Moroney wrote:
> >> Serg Io <invliad@invalid.com> writes:
> >
> > Holding a consistent userID handle could serve to improve content quality.
> 
> totally agree,
> 	the "Denk vs. McGinn" discussions
> 	keep out sellers of wasteland, not even useful for neclear dumps.
> 
> >
> >>> Is sci.physics now 100 % clutter ?
> >>
> >>>        any real physics at all being posted ?
> >
> > Physics is complicated, not a rehashTag@# of contents in its textbooks.
> 
> there is a lot of knowledge in sci.physics, I learned from sci.physics 
> that one can buy/use high viscosity silicone differential fluid for 
> model RC racing on Photomulitplier tubes to scintillator connections.
> 
> Books do not have the practical working side of physics, where this 
> group can really contribute.
> 
> >
> >> Thanks for trying to inject some actual science here, but to answer your
> >> question, yes, sci.physics is now just a looney bin.
> >
> > If by now is meant since 1990s, then the looney has just grown, as of late.
> > Used to be a time, a large number of posters here had *.edu domain named
> > email addresses. I've not seen one here, since I returned to Usenet,
> > like six years ago. Must have something to do with new universities' policies.
> 
> Microsoft/google has slowly and sucessfully strangled off access to the 
> usenet via its browsers, so a person that just bought a computer has no 
> idea the usenet exists.  There are some sites that re-broadcast the 
> forums, like drexial and others.  So most of the users are older ones 
> that know how, or still can connect to usenet, and the younger ones 
> prefer to go to the sites with pictures, videos, active content, not 
> text, etc.
> 
> 
> 
> >
> > Many here, there, or anywhere... are not just going to simply worship OneStone.
> 
> supporting ideas or beliefs is needed to re-inforce self esteem, even 
> oddball ones.
> 
> somehow sci.physics posters have arrived here, prescreened by past 
> knowledge (older age), and perhaps by no forum in which they would get 
> a responce.
> 
> 
> >
> > -- Mahipal “IPMM... माहिपाल ७६३८: d(me) != 0 ... me alwa(y)s changes...”
> >

Must be like a nightmare to you.  What are you going to do. Cut and paste more irrelevancies, get a new sock puppet handle?  

You seem bitter, inconsolable.

Maybe you should avoid science.

Poor dumb Ed Prochak. Look what happened to him.

What a shame.

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