On Jul 15, 5:38 pm, Jeff Liebermann wrote:

Radium hath wroth:

AFAIK, the main issue with AM is that it is much more vulnerable to
magnetic disruptions than FM.

Wrong. Take a magnet, any magnet. Wave it around your AM or FM
radio. Hear anything different? You won't. Therefore, forget about
magnetic disturbances.

That's because this magnet isn't vibrating fast enough. If it were to
vibrate at the carrier frequency, you would most likely hear
something.

Also, if there is a solar prominence you can hear the resulting
magnetic disruptions on an AM radio receiver. They sound scary and
enjoyable at the same time.

You can also hear lightning storms. In the US, most of those are in
the south east of the country. Nothing like interference from 3000
miles away. Lightning detectors operate in the 25-50KHz region.
Incidentally, there are about 8 million lightning hits per day, which
is why the noise sounds almost continuous.

The AM audio cause by lightning is so boring. All you get are clicks
and pops. Now a solar prominence, this results in some terrifying
tones on the AM radio, they resemble the second set of tones played by
the Emergency Alert System -- the higher-pitched tones. At times the
cosmically-induced AM radio disruptions sound like the audio you get
when playing the 1st level of the 1st-stage of Super Mario Bros 1 on
channel 4, when the receiver is connected to channel 3. Instead of
hearing the game's music, you here those frightening yet enjoyable
tones. Sometime you can here these same sounds on a PA system or an
airplane. When I was in 1st-grade, the schoolbus I went in had a CB
radio which would often make these scary sounds. Such sounds would --
and still to a much smaller extent -- make my eyes water in fear,
dissociation, enjoyment, and psychdelia.

When the sun emits a prominence, that prominence causes high-power
waves of magnetic energy in the RF region to be emitted. These waves
can be heard on the AM radio on Earth. This is the sound that affects
CBs and other radio receivers using AM.

The main reason why anyone would prefer FM over AM is if they can't
handle these terrifying sounds w/out going hysterical.

There are some who have had emotionally-strong experiences with these
sounds -- perhaps a fire on an aircraft -- when these sounds are
heard, flashbacks occur which can entirely consume an individual's
psyche. Such an individual might not even know why he/she is getting
psychologically-excited while listening to the sounds because the
brain involuntarily suppresses emotionally-intense memories.

Here is what use to happen -- and still happens to some extent -- to
me when I hear the sounds I describe:

1. Psychogenic shock and psychological dissociation due to the extreme
fear/enjoyment caused by the sounds.
2. Flashbacks of my house in Stamford, Connecticut in which my parents
and me moved out when I was around 2.5 years of age.
3. Enjoyable yet terrifying thoughts about outer space due to the
knowledge/belief that the source of the sounds is in outer space
4. Fear of -- and obsession with -- magnetism due to knowledge/belief
that the radio waves are magnetic
5. Decrease in heart rate
6. Slow deep breathing
7. Muscle relaxation
8. Increased tear production

Ain't it interesting when things that are so scary are also so
enjoyable at the same time. Why else would they develop virtual
reality systems? Or visit outer space?

We tend to enjoy what we fear. At times.

Jeff Liebermann wrote:

snip
I have a fluorescent lamp calibrated noise source that's quite noisy
well into the GHz range.

Sounds interesting.

Would you please post some details or pointers to references about
constructing and calibrating such an instrument?

Regards,

Michael

"Radium" wrote in message
oups.com...
On Jul 1, 7:24 am, wrote in
http://groups.google.com/group/sci.e...0c8ed13?hl=en&
:

how would u like to change the cell phone industry?

Analog cells phones should stop using FM and should start using AM
with SHF frequencies - at least 3 GHz and at most 30 GHz.

Maybe you should spend more time reading up on Radio systems, RF
propagation, Modulation techniques, and a whole range of other RF and
electronic related material, before you once again make a fool of yourself.

Jeff Liebermann wrote:

Radium hath wroth:

snip
That is why when you are listening to
the AM radio at home and someone turns on the microwave-oven, you here
those odd sounds on the receiver.


No. Microwave ovens operate at 2400Mhz. AM broadcast operates at
1MHz. No way there's going to be any interference there.

I have an oven with a bit too much leakage; various components in some
of my broadcast and hf receivers make good antennas at 2.4GHz and as the
stirrer rotates in the oven, the signal level changes (60 Hz modulation
of course).

Regards,

Michael

Radium hath wroth:

On Jul 15, 5:38 pm, Jeff Liebermann wrote:

Radium hath wroth:

AFAIK, the main issue with AM is that it is much more vulnerable to
magnetic disruptions than FM.

Wrong. Take a magnet, any magnet. Wave it around your AM or FM
radio. Hear anything different? You won't. Therefore, forget about
magnetic disturbances.

That's because this magnet isn't vibrating fast enough. If it were to
vibrate at the carrier frequency, you would most likely hear
something.

Actually, what you'll hear is whatever is driving the magnet at the
carrier frequency. For example, if you shove the magnet into a
solenoid coil, and drive the coil at 1MHz, the magnet will move very
slightly at 1MHz. However, the crud that you'll hear at 1MHz is
coming from the solenoid coil, not the magnet. If the magnetic field
cuts across some wire, that happens to be the antenna of your 1MHz
receiver, then yes, you'll hear something, but only if it's moving at
1MHz.

The AM audio cause by lightning is so boring.

If you've ever been hit by lightning, I don't think you'll find it
very boring. With 8 million hits per day, chances are good that
you'll get hit. Ummm... could you step outside for a moment?

All you get are clicks
and pops.

Oh no. It's much better than that. You get snap, crackle, pop,
crash, hiss, zap, buzz, braaaaaap, and other noises, all to the
accompanyment of loud thunder and the smell of ozone. It can also
make the fur stand up on your back. If all you hear are clicks and
pops, your receiver is comatose.

When the sun emits a prominence, that prominence causes high-power
waves of magnetic energy in the RF region to be emitted. These waves
can be heard on the AM radio on Earth. This is the sound that affects
CBs and other radio receivers using AM.

Ummm... coronal mass ejections and solar flares are particles, not
radio waves. The interference to radio communications is mostly from
these particles effects on the ionospheric layers. There is some RF
involved, but it's at microwave frequencies and requires a big radio
telescope to see.
http://www.nrao.edu/pr/2001/radiocme/

The main reason why anyone would prefer FM over AM is if they can't
handle these terrifying sounds w/out going hysterical.

Hmmm... All my communications radios except the aircraft navcom stuff
is FM. Maybe that explains why I'm spending time explaining to you
the basics. I'll try not to get too hysterical.

There are some who have had emotionally-strong experiences with these
sounds (...)

Not a problem. Everyone knows that too much RF rots the brain and
causes cancer of the vocabulary. Anyone involved in RF has to be
insane or will shortly be insane.

(chop...)

We tend to enjoy what we fear. At times.

I don't fear anything, so that might explain why I'm not enjoying
myself.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

msg hath wroth:

Jeff Liebermann wrote:

snip
I have a fluorescent lamp calibrated noise source that's quite noisy
well into the GHz range.

Sounds interesting.

Would you please post some details or pointers to references about
constructing and calibrating such an instrument?

Groan. I built it myself from an article in some long lost magazine
perhaps 30 years ago. It's just a 5watt fluorescent tube, with a few
turns of wire wrapped around it going to a broadband CATV amplifier.
One end of the wire coil is terminated at 50 ohms. The other end goes
to the broadband amp. The lamp is powered by a heavily filtered
isolation xformer. Calibration consisted of taking a scope photo of
the output on a spectrum analyzer. Just about any gas discharge tube
will work. Neon, fluorescent, blue or green gas discharge display,
the new compact fluorescent tubes, plasma tube TV, etc.

Most older microwave noise sources use argon filled gas discharge
tubes, but fluorescent will sorta work. The HP 346A (3-18GHz) and
349A (0.4 to 4GHz) noise sources are examples of such gas discharge
tube test noise sources. The manual for the 342A NF test system,
which includes the 349A noise source is at:
ftp://bama.sbc.edu/downloads/hp/342a/342a_349a_service_6.pdf
See section 5.

Some minor notes around Fig 9.24 on Page 207 at:
http://books.google.com/books?id=sNLQmi3ymTYC&pg=PA206&lpg=PA206

I could post some photos, but I really don't want to tear it apart to
take pictures of the guts.

These daze, microwave noise sources use avalanche diodes although just
about any diode with a sharp knee will work. Diodes are more stable,
less fragile, and easier to produce than gas discharge tubes.
http://www.ham-radio.com/sbms/sd/nfsource.htm
http://www.atmmicrowave.com/coax-noise.html

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sun, 15 Jul 2007 16:30:13 -0700, Jeff Liebermann
wrote:


Not really. If you really want weak signal reception, I suggest you
look into SSB (scientific set back) modulation.

what??!! ^^^^^^^^^^^^^^^^^^^


John

In rec.radio.amateur.antenna John Larkin wrote:
On Sun, 15 Jul 2007 16:30:13 -0700, Jeff Liebermann
wrote:


Not really. If you really want weak signal reception, I suggest you
look into SSB (scientific set back) modulation.

what??!! ^^^^^^^^^^^^^^^^^^^

Too subtle for you?

It's called humor.

--
Jim Pennino

Remove .spam.sux to reply.

John Larkin hath wroth:

On Sun, 15 Jul 2007 16:30:13 -0700, Jeff Liebermann
wrote:
Not really. If you really want weak signal reception, I suggest you
look into SSB (scientific set back) modulation.

what??!! ^^^^^^^^^^^^^^^^^^^

Sigh. Nobody here seems to have a sense of humor.
SSB = Single Side Band
Happy now? You sure take the fun out of acronym mutilation.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote:
If you've ever been hit by lightning, I don't think you'll find it
very boring. With 8 million hits per day, chances are good that
you'll get hit. Ummm... could you step outside for a moment?

Reminds me of an afternoon when I was 600 ft up a 1,000 ft TV tower
climbing on the inside. The tower took a hit and the lightning bolt
followed a aircraft cable hoist line down the inside of the tower. Right
between my legs.