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Old July 1st 07, 08:16 PM posted to sci.electronics.basics,rec.radio.shortwave,rec.radio.amateur.antenna,alt.cellular.cingular,alt.internet.wireless
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Default AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency

On Jul 1, 7:24 am, wrote:
radium, I applaud you in your interest generating discussion.

if there are no questions there are no answers; dumb or smart!

to me your questions came across wonderfully, and generated both
responses.

as humans we stand on two legs, most of us that is.

men get the honor and privilage to stand on three legs from time to
time.

this is our blessing and our curse!


Thanks for your understanding.

ps. how would u like to change the cell phone industry?


Analog cells phones should stop using FM and should start using AM
between frequencies of 40,000 to 285,000 Hz.

As I learned recently, 40 KHz is the minimum radio frequency required
to coherently transmit/receive audio signals. The highest sound a
human can hear is 20 KHz. The radio-frequency used must be at least 2x
the intended frequency of the information being transmitted/received.

I chose 285 KHz to be the highest radio frequency for cell-phones
because it is roughly the highest-frequency categorized as "long wave"
radio.

and your
discussion group of course!


You mean the anti-yahoo group?

http://groups.google.com/group/yahoo...s?lnk=li&hl=en

  #72   Report Post  
Old July 1st 07, 08:50 PM posted to sci.electronics.basics,rec.radio.shortwave,rec.radio.amateur.antenna,alt.cellular.cingular,alt.internet.wireless
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Default "Radium" [email protected] COMPLETE IDIOT..........


"Radium" wrote in message
oups.com...
On Jul 1, 7:24 am, wrote:
Analog cells phones should stop using FM and should start using AM
between frequencies of 40,000 to 285,000 Hz.

I chose 285 KHz to be the highest radio frequency for cell-phones
because it is roughly the highest-frequency categorized as "long wave"
radio.



IDIOT!......complete idiot......


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Old July 1st 07, 09:01 PM posted to sci.electronics.basics,rec.radio.shortwave,rec.radio.amateur.antenna,alt.cellular.cingular,alt.internet.wireless
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Default AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency

On Sun, 01 Jul 2007 12:16:35 -0700, Radium
wrote:

On Jul 1, 7:24 am, wrote:
radium, I applaud you in your interest generating discussion.

if there are no questions there are no answers; dumb or smart!

to me your questions came across wonderfully, and generated both
responses.

as humans we stand on two legs, most of us that is.

men get the honor and privilage to stand on three legs from time to
time.

this is our blessing and our curse!


Thanks for your understanding.

ps. how would u like to change the cell phone industry?


Analog cells phones should stop using FM and should start using AM
between frequencies of 40,000 to 285,000 Hz.


---
Good idea. The available spectrum between 40kHz and 285kHz is
245kHz wide, so at a little less than 3kHz per channel the maximum
number of channels available would be 82. That means that no more
than 82 people can be on the air at the same time.

Probably all over the world, to boot, what with those frequencies
being able to propagate over long distances.

That's probably a good thing, because with those 1875 meter long 1/4
wave whips at 40kHz and those 263 meter 1/4 wave whips at 285kHz on
the mobiles, any more people on the air than that would certainly
create a hazardous situation.


--
JF
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Old July 1st 07, 10:04 PM posted to sci.electronics.basics,rec.radio.shortwave,rec.radio.amateur.antenna,alt.cellular.cingular,alt.internet.wireless
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Posts: 286
Default AM electromagnetic waves: 20 KHz modulation frequency on anastronomically-low carrier frequency

On 7/1/07 11:53 AM, in article , "John Smith I"
wrote:

Don Bowey wrote:

[more crap!]


Oh, that explains it, your understanding of amplitude modulation is:

AM = Black Magic.

ROFLOL!

JS


OK you stupid ****, I'm almost out of patience with your ignorance. I was
hoping you might learn something, but I see that is unlikely.

AM is a process of frequency multiplication. Now you tell me where you
think such multiplication takes place on a phone line, and I'll follow-uo by
telling why you're full of crap.

SIMECS!

  #75   Report Post  
Old July 1st 07, 10:09 PM posted to sci.electronics.basics,rec.radio.shortwave,rec.radio.amateur.antenna,alt.cellular.cingular,alt.internet.wireless
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Posts: 286
Default AM electromagnetic waves: 20 KHz modulation frequency on anastronomically-low carrier frequency

On 7/1/07 12:16 PM, in article
, "Radium"
wrote:

On Jul 1, 7:24 am, wrote:
radium, I applaud you in your interest generating discussion.

if there are no questions there are no answers; dumb or smart!

to me your questions came across wonderfully, and generated both
responses.

as humans we stand on two legs, most of us that is.

men get the honor and privilage to stand on three legs from time to
time.

this is our blessing and our curse!


Thanks for your understanding.

ps. how would u like to change the cell phone industry?


Analog cells phones should stop using FM and should start using AM
between frequencies of 40,000 to 285,000 Hz.

As I learned recently, 40 KHz is the minimum radio frequency required
to coherently transmit/receive audio signals. The highest sound a
human can hear is 20 KHz. The radio-frequency used must be at least 2x
the intended frequency of the information being transmitted/received.

I chose 285 KHz to be the highest radio frequency for cell-phones
because it is roughly the highest-frequency categorized as "long wave"
radio.

and your
discussion group of course!


You mean the anti-yahoo group?

http://groups.google.com/group/yahoo...s?lnk=li&hl=en


Darn it Radium, you just hit a new low.

See that teeney antenna on cell phones? Just how well do you think it will
radiate 285 kHz?



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Old July 1st 07, 10:11 PM posted to sci.electronics.basics,rec.radio.shortwave,rec.radio.amateur.antenna,alt.cellular.cingular,alt.internet.wireless
RHF RHF is offline
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First recorded activity by RadioBanter: Jun 2006
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Default "Radium" a COMPLETE IDIOT... - More Likely An In-Complete-Want-To-Be [.]

On Jul 1, 12:50 pm, "Porgy Tirebiter" wrote:
"Radium" wrote in message

oups.com...

On Jul 1, 7:24 am, wrote:
Analog cells phones should stop using FM and should start using AM
between frequencies of 40,000 to 285,000 Hz.


I chose 285 KHz to be the highest radio frequency for cell-phones
because it is roughly the highest-frequency categorized as "long wave"
radio.


- IDIOT!......complete idiot......

PT - Once again why waste your time replying
to his posts ? ? ? {Oops Like I Am Doing Too !}

Actually "Radium" would appear to be an
In-Complete-Want-To-Be driven by the 'urge'
to Post these Forever Ponding Questions
for others to charge at like Don Quijote's
quest to slay Windmills {a fool's errand}
http://en.wikipedia.org/wiki/Don_Quixote
http://en.wikipedia.org/wiki/Fool%27s_errand

FWIW - While many of his Post might fit into
the "sci.electronics.basics" NewsGroup; often
they would be consider OFF-TOPIC in other
NewsGroups like : rec.radio.shortwave,
rec.radio.amateur.antenna, alt.cellular.cingular,
alt.internet.wireless, etc

IMHO - In another life "Radium" would have
made a great High School Science Teacher :
Who's Students when on to do great things
with their lives :
Because "Radium" Touched Them With A Thirst
For Knowledge And A Quest For Answers.

-but- These NewsGroups are NOT a High School
Science Class -and- "Radium" is just being 'radium'.
http://en.wikipedia.org/wiki/Radium

-alas- Our "Radium's" Half-Life of Readable Interest
http://en.wikipedia.org/wiki/Half-life
is at best about 16.04 Seconds ~ RHF
  #77   Report Post  
Old July 1st 07, 10:22 PM posted to sci.electronics.basics,rec.radio.shortwave,rec.radio.amateur.antenna,alt.cellular.cingular,alt.internet.wireless
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First recorded activity by RadioBanter: Jun 2007
Posts: 1,336
Default AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency

Radium hath wroth:

ps. how would u like to change the cell phone industry?


Analog cells phones should stop using FM and should start using AM
between frequencies of 40,000 to 285,000 Hz.


Analog cell phones are going to be history in the US on Feb 18, 2008.
Japan killed off analog around June 1999, Korea in Jan 2000, most of
Europe in 1997, etc.

40KHz thru 285Khz? Great idea. Just one minor problem. A 1/4 wave
antenna at about 100Khz frequency is 750 meters long. That's going to
be a rather large antenna for literally dragging behind you. Maybe a
balloon? Maybe a loop like this one?
http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=10850
Of course propagation might be a problem, as it will only work at
night and you'll have to connect to a cell site on the opposite coast
for those frequencies to work. The customers can be ignored when they
complain about atmospheric static and noise.

Of course, 240KHz of usable bandwidth is much less than the hundreds
of MHz currently in use by cellular providers, so there will
substantially fewer users. Let's see.... there are 240 million
subscribers in the US. Your AM system can handle about 40 users (6KHz
channels), so your cell phone bill will only be 6 million times larger
than it is currently. Now do you see why the microwave bands are so
in demand for cellular.

As I learned recently, 40 KHz is the minimum radio frequency required
to coherently transmit/receive audio signals.


Coherently? I would be worried if you planned to incoherently
transmit/receive audio signals. Perhaps if you added 40KHz to your
word salad, it would make your blather more coherent. (Hint: Look
up the definition of coherent and then use it where appropriate).

Actually, you're close. 40KHz is the common frequency used by
ultrasonic TV remote controls. I've seen PWM modulation system using
a pair of these to act as a crude cordless phone (that doesn't require
FCC type certification). You could probably go down to 20KHz, but
then intermodulation products (mixes) between the audio and the
carrier will begin to be a problem. Congratulations, you got one
thing mostly correct.

The highest sound a
human can hear is 20 KHz.


Voice is from 300 to 3000Hz. You could probably get away with 300 to
2400Hz. If you're planning to transmitting AM hi-fi or data, then you
might need the 20KHz.

The radio-frequency used must be at least 2x
the intended frequency of the information being transmitted/received.


Ummm... no. You're apparently thinking of the Shannon rule for
information bandwidth:
http://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem
If your input audio is perhaps bandwidth limited to 3KHz, a 6KHz
carrier will not work. You'll get considerable mixing (aliasing) and
audio intermodulation crud. The carrier would need to be somewhat
higher in frequency as limited by whatever output RF filtering is
used.

I chose 285 KHz to be the highest radio frequency for cell-phones
because it is roughly the highest-frequency categorized as "long wave"
radio.


Nope. See details at:
http://en.wikipedia.org/wiki/Longwave


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #78   Report Post  
Old July 1st 07, 10:28 PM posted to sci.electronics.basics,rec.radio.shortwave,rec.radio.amateur.antenna,alt.cellular.cingular,alt.internet.wireless
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First recorded activity by RadioBanter: Jul 2006
Posts: 286
Default "Radium" a COMPLETE IDIOT... - More Likely AnIn-Complete-Want-To-Be [.]

On 7/1/07 2:11 PM, in article
, "RHF"
wrote:

On Jul 1, 12:50 pm, "Porgy Tirebiter" wrote:
"Radium" wrote in message

oups.com...

On Jul 1, 7:24 am, wrote:
Analog cells phones should stop using FM and should start using AM
between frequencies of 40,000 to 285,000 Hz.


I chose 285 KHz to be the highest radio frequency for cell-phones
because it is roughly the highest-frequency categorized as "long wave"
radio.


- IDIOT!......complete idiot......

PT - Once again why waste your time replying
to his posts ? ? ? {Oops Like I Am Doing Too !}

Actually "Radium" would appear to be an
In-Complete-Want-To-Be driven by the 'urge'
to Post these Forever Ponding Questions
for others to charge at like Don Quijote's
quest to slay Windmills {a fool's errand}
http://en.wikipedia.org/wiki/Don_Quixote
http://en.wikipedia.org/wiki/Fool%27s_errand

FWIW - While many of his Post might fit into
the "sci.electronics.basics" NewsGroup; often
they would be consider OFF-TOPIC in other
NewsGroups like : rec.radio.shortwave,
rec.radio.amateur.antenna, alt.cellular.cingular,
alt.internet.wireless, etc

IMHO - In another life "Radium" would have
made a great High School Science Teacher :
Who's Students when on to do great things
with their lives :
Because "Radium" Touched Them With A Thirst
For Knowledge And A Quest For Answers.


But a teacher MUST be rational. You rate Radium with more potential than I
can. This most recent post is really off the wall.



-but- These NewsGroups are NOT a High School
Science Class -and- "Radium" is just being 'radium'.
http://en.wikipedia.org/wiki/Radium

-alas- Our "Radium's" Half-Life of Readable Interest
http://en.wikipedia.org/wiki/Half-life
is at best about 16.04 Seconds ~ RHF
.
.
. .


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Old July 1st 07, 10:44 PM posted to sci.electronics.basics,rec.radio.shortwave,rec.radio.amateur.antenna,alt.cellular.cingular,alt.internet.wireless
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First recorded activity by RadioBanter: May 2007
Posts: 92
Default AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency


"Ian Jackson" wrote in message
...
In message , cledus
writes


snip


The fundamental answer is no, it is not possible to generate AM where the
baseband signal is a pure 20 kHz sinewave and Fc20kHz. The reason is
that the modulated waveform consists of the sum of a sinewave at Fc, a
sinewave at Fc+20kHz, and a sinewave at Fc-20kHz. If Fc20kHz then one of
the components becomes a "negative" frequency. So the carrier must be
greater than the baseband signal to prevent this.

I'm afraid that this is not correct. The 'laws of physics' don't suddenly
stop working if the carrier is lower than the modulating frequency.
However, there's no need to get into complicated mathematics to illustrate
this. Here is a simple example:

(a) If you modulate a 10MHz carrier with a 1MHz signal, you will produce
two new signals (the sidebands) at the difference frequency of 10 minus 1
= 9MHz, and the sum frequency of 10 plus 1 = 11MHz. So you have the
original carrier at 10MHz, and sideband signals at 9 and 11MHz (with a
balanced modulator - no carrier - only 9 and 11MHz).

(b) If you modulate a 1MHz carrier with a 10MHz signal, you will produce
two new signals (the sidebands) at the difference frequency of 1 minus 10
= minus 9MHz, and the sum frequency of 1 plus 10 = 11MHz. The implication
of the negative 'minus 9' MHz signal is that the phase of the 9MHz signal
is inverted, ie 180 degrees out-of-phase from 9MHz


Actually there would be no phase flip.
cos(-a) = cos(a)

produced in (a). So you have the original carrier at 1MHz, and sidebands
at 9 and 11MHz (again, with a balanced modulator - no carrier - only 9 and
11MHz).

The waveforms of the full composite AM signals of (a) and (b) will look
quite different. The carriers are at different frequencies, and the phase
of the 9MHz signal is inverted. However, with a double-balanced modulator,
you will only have the 9 and 11MHz signal so, surprisingly, the resulting
signals of (a) and (b) will look the same.


A double-balanced mixer is a multiplier. A * B = B * A


[Note that, in practice, many double-balanced modulators/mixers put loads
of unwanted signals - mainly due the effects of harmonic mixing. However,
the basic 'laws of physics' still apply.]

Finally, although I have spoken with great authority, when I get a chance
I WILL be doing at test with a tobacco-tin double-balanced mixer,


What's a tobacco-tin double-balanced mixer?

a couple of signal generators and a spectrum analyser - just to make sure
that I'm not talking rubbish. In the meantime, I'm sure that some will
correct me if I'm wrong.


You did pretty good.


Ian.
--


--
rb


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Old July 1st 07, 10:54 PM posted to sci.electronics.basics,rec.radio.shortwave,rec.radio.amateur.antenna,alt.cellular.cingular,alt.internet.wireless
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First recorded activity by RadioBanter: Mar 2007
Posts: 65
Default AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-lowcarrier frequency

Jeff Liebermann wrote:

40KHz thru 285Khz? Great idea. Just one minor problem. A 1/4 wave
antenna at about 100Khz frequency is 750 meters long. That's going to
be a rather large antenna for literally dragging behind you.


Well, your math is correct. However, the so-called "atomic" wrist
watches receive their time signal from WWVB which transmits at 60kHz.

How do they get that 1250 meter long antenna ( 1/4 wave at 60 kHz)
inside that itty bitty wrist watch case? ;-)

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