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

Radium wrote:
FM has too much hiss. FM signals are lost very easily. AM tends to
retain reception of a signals even when this signal is extremely weak.
In FM, once you go below a certain wattage, you completely lose the
signal, and the annoying hiss begins. With AM it is much easier to
receive the low-power signal.

AM maybe more vulnerable to electronic disturbances but so what? The
magnetic RF interferences that are heard on the AM radio are
entertaining compared to the deafening hiss on the FM radio.

I really do think you need to revisit some VERY basic principles of
communications theory.

It sounds like you might have a causal peripheral understanding of
communications theory and stumbled upon some obscure radio propagation
concept and want to apply that obscure concept to to change the whole way
we think of communications. Ponder for a moment why said obscure concept
remained obscure.

I could go on and on and pick each of your comments apart...but it would be
a waste of time.

In rec.radio.amateur.antenna DTC wrote:
Radium wrote:
FM has too much hiss. FM signals are lost very easily. AM tends to
retain reception of a signals even when this signal is extremely weak.
In FM, once you go below a certain wattage, you completely lose the
signal, and the annoying hiss begins. With AM it is much easier to
receive the low-power signal.

AM maybe more vulnerable to electronic disturbances but so what? The
magnetic RF interferences that are heard on the AM radio are
entertaining compared to the deafening hiss on the FM radio.

I really do think you need to revisit some VERY basic principles of
communications theory.

You're assuming he ever did anything more than assemble a list of
technical buzz words to string together at random.

Malaprop Man from the Frank and Ernest comic strip makes more sense.

--
Jim Pennino

Remove .spam.sux to reply.

wrote in message
...
You're assuming he ever did anything more than assemble a list of
technical buzz words to string together at random.

In this same spirit, I have decided how I would like to change the
electric toaster industry.

I believe that henceforth, all electric toasters should be made from
polished unobtainium with "Q"-shaped dilithium heating elements,
as it is obvious that this results in more even toasting of the bread
and an undeniably higher-fidelity output. Further, the toasted bread
should be ejected by carefully-aligned cavorite lifters, timed by
observing both the thermal state of the bread (detected through
counts of left-hand circular polarized neutrino emissions) and the
state of a resublimated thiotimoline crystal being exposed to the
transverse-modulated IR spectrum.

Discuss!

Bob "The New Radium" M.

DTC hath wroth:

It sounds like you might have a causal peripheral understanding of
communications theory and stumbled upon some obscure radio propagation
concept and want to apply that obscure concept to to change the whole way
we think of communications. Ponder for a moment why said obscure concept
remained obscure.

I could go on and on and pick each of your comments apart...but it would be
a waste of time.

Quite the contrary. Taking apart rants and speculation from the
lunatic fringe is great fun. After one has mastered science and
technology, it offers an additional challenge.

Haven't you ever listened to the old Art Bell show? He collected
callers claiming alien visitations, abductions, flying saucers,
conspiracies, ghosts, amazing technology, and all kinds of other
observed phenomenon best attributable to a general lack of sanity and
education. He would treat them quite seriously, drawing out
additional details that seem to fascinate his large and diverse
audience. My guess(tm) is that reality and accurate science are
fundamentally boring, and that speculation, lunacy and fantasy are
suitable diversions. Some of his callers held prestigious academic or
government positions, and apparently wanted to how far off the deep
end they could go. I recognized one or two. To properly present a
pseudoscientific hoax requires a good understanding of the science and
technology, and not just a word salad of buzzwords.

I must confess that I enjoy doing the same thing, as witnessed by this
ummm.... discussion. Lacking a suitable solution to the general lack
of technical sanity problem, I find it far more interesting to become
part of the problem. For example, my rants on being a werewolf:
http://www.LearnByDestroying.com/nooze/werewolf.txt

http://en.wikipedia.org/wiki/Art_Bell
In 1998, Bell was named as recipient of the less-than-prestigious
Snuffed Candle Award. The Council for Media Integrity cited Bell
"for encouraging credulity, presenting pseudoscience as genuine,
and contributing to the public's lack of understanding of the
methods of scientific inquiry."

That's why it's called "the magic of radio". When the magic wears
off, what's left is boring and mundane science and physics.

--
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:
[radically snipped]
Haven't you ever listened to the old Art Bell show?
Some of his callers held prestigious academic or
government positions, and apparently wanted to how far off the deep
end they could go.

I could be wrong as I'm going back to a late night show over five years ago
and I seem to recall it was one of his.

He was talking about GPS and played back a snippet of a conversation of
above mentioned prestigious academic person that went ballistic trying to
validate his credentials. But I digress...

I so wanted to point out that Art's (if indeed it was his show) was a
disingenuous presentation of GPS as it led the less informed to believe
there was a very dark and pervasive side to GPS. Continuing the only good
aspects of GPS were promoted by manufactures and dealers of GPS systems.

Good or bad...the bottom line was he attracted an audience and an audience
translates to advertising revenues.

"Jeff Liebermann" wrote in message
...
audience. My guess(tm) is that reality and accurate science are
fundamentally boring,

I think a lot of people perceive them as such, but that
perception is, without fail in my experience, the result of
a nearly-complete ignorance of these subjects on the parts
of those people. There are a practically infinite number
of incredibly interesting, beautiful, weird, mind-blowing things
going on in real science - if anything, it's the speculation,
lunacy, and fantasy that winds up looks really dull, if you
have any sort of understanding of the real world. Most of
what passes for interesting material on the Art Bell show
would be kicked out as too dull, too unimaginative, and/or too
mundane by any decent science-fiction editor.

Bob M.

"Jeff Liebermann" wrote in message
...
I'll make it really simple for you. FM is "hi-fi", while AM is noisy
"no-fi". Don't you want to be cool strutting down the street with
your iPhone watching HDTV with 7.1 sound? It wouldn't do to have it
sound like the typical AM broadcast station. For decent quality, you
gotta have FM.

FM is not inherently any more 'hi-fi' than AM. Fidelity is a product of
bandwidth, not modulation type. AM is not even so susceptible to noise as
the frequency goes up, since the energy of the noise pulses goes down
logarithmically as frequency goes up. AM is used for aeronautical
communications very successfully for several reasons, one of which is the
LACK of 'capture effect'. There are still some frequencies where AM will be
more susceptible to interference than FM, but FM would still suffer, for
instance the segment between 1330-1400 MHz which is the natural frequency of
Hydrogen (lots of that around).

"Brenda Ann" hath wroth:

"Jeff Liebermann" wrote in message
.. .
I'll make it really simple for you. FM is "hi-fi", while AM is noisy
"no-fi". Don't you want to be cool strutting down the street with
your iPhone watching HDTV with 7.1 sound? It wouldn't do to have it
sound like the typical AM broadcast station. For decent quality, you
gotta have FM.

FM is not inherently any more 'hi-fi' than AM.

FM was invented by Edwin Armstrong specifically to eliminate the noise
problems of AM broadcasting. What I think you might be referring to
is the huge ****ing match between Armstrong and John Carson over
whether FM was any better than FM in the 1930's. The consensus is
that very narrow band FM isn't that much better than AM (of equal
occupied bandwidth), but wide band FM (as used in broadcast FM and TV)
is far better than AM for just about everything.
http://fecha.org/armstrong.htm

Fidelity is a product of
bandwidth, not modulation type.

Correct. Actually, it's also a function of modulation linearity
(distortion and intermod) and encoding method (dynamic range), but I
don't wanna slither down that diversion. Pretend I didn't mention it.

AM is not even so susceptible to noise as
the frequency goes up, since the energy of the noise pulses goes down
logarithmically as frequency goes up.

If you're thinking of impulse noise, you're mostly correct. However,
there are plenty of other sources of AM noise available. For example,
the typical VHF aircraft radio requires substantial filtering of the
magneto to avoid hash. Same with any onboard motor. If you've ever
tried to install a TV (VSB is a form of AM) in a vehicle, you'll also
find that ignition and motor noise can be a problem.

Also, your statement isn't quite right. I think what you meant to say
is that as the frequency increases, the energy produced by an impulse
source, in a given bandwidth, goes down. Even that's not accurate as
I have a fluorescent lamp calibrated noise source that's quite noisy
well into the GHz range.

AM is used for aeronautical
communications very successfully for several reasons, one of which is the
LACK of 'capture effect'.

The FAA, FCC, and various manufactories have tried to move aircraft
radios away from AM and towards FM several times in the past 30 year
or so. They failed mostly due to international WRC reluctance to swap
out expensive radios. It took literally forever to get GPS receivers
TSO approved and about 15 years for nav/com radios to go from 50KHz to
25KHz channel spacing, and that was just the FAA. Where else can you
find an industry, where progress is somewhat retarded by a regulatory
agency of the federal government?

I listen to a mix of VHF aircraft AM channels and FM ham and public
safety channels on my scanner almost constantly. It's easy to
recognize the AM stations by their uniformly crappy audio.

Most domestic ground to ground airport traffic is now all FM, as is
military ground to ground and ground to air. The reason is that it's
difficult to find a decent AM aircraft band walkie talkie. So, they
use commercial FM radios. The only AM walkie talkies are used by
experimental aviation and ultralights, some of which do not have much
of an electrical system that can handle the grossly inefficient AM
transmitters.

Also, nobody really cares about the "capture effect" as the tower
usually has multiple receiver sites and can generally deal with
simultaneous transmit collisions. However, they do care about the
heterodynes produced by simultaneous transmissions, which obliterate
both transmissions. With FM, they could use commercial receiver
voting systems and largely eliminate the problem.

There are still some frequencies where AM will be
more susceptible to interference than FM, but FM would still suffer, for
instance the segment between 1330-1400 MHz which is the natural frequency of
Hydrogen (lots of that around).

If my AM or FM receiver is sensitive enough to hear something in the
"water hole", it would be attached to a very big dish antenna.


--
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:

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