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#21
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How I would like to change the cell phone industry [was AM
Jeff Liebermann wrote:
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. Dang it...my memory is slipping. What did Motorola call their noise filtering circuit on their old low band Motracs. Extenders[tm]? As I recall it was a simple noise blanker. |
#22
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How I would like to change the cell phone industry [was AM
Radium wrote:
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. I was not aware there was a compelling reason for analog cell phones to stop using FM. Sounds like a solution looking for a problem. |
#23
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How I would like to change the cell phone industry [was AM
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. |
#24
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How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
DTC hath wroth:
Jeff Liebermann wrote: 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. Dang it...my memory is slipping. What did Motorola call their noise filtering circuit on their old low band Motracs. Extenders[tm]? As I recall it was a simple noise blanker. "Extender". It was a 2nd almost identical receiver, tuned to a nearby empty frequency. If there was any impulse (ignition) noise, both receivers would detect the pulses. The 2nd (Extender) receiver would block the IF signal in the main receiver for the duration of the pulse. This resulted in a "hole" in the receive IF and audio, but it was far less noticeable than if the pulse were allowed to be heard. The tricky part of the design was getting the delays nearly identical in the two receivers. It also made the 80D/140D/Motrac/Motran radios rather huge and heavy. Extenders were considered a "standard option" on most Low Band (30-50Mhz) radios as this is where the ignition noise is the worst. The more generic term "noise blanker" applies to this scheme, as well as a mess of others that detect in a single receiver or blank in the IF or audio. GE decided that "extender" was a good name for their mobile repeater, and called it a "mobile extender" or more commonly just "extender". http://www.mbay.net/~wb6nvh/chpradio.htm Egads. I'm cleaning house and found a large box of 40 year old Motrash control heads and cables. Want some junk? There was also a scheme to eliminate ignition noise that involved running a wire to the points on the distributor. The assumption was that there was a substantial delay between when the points opened, and when the spark jumped in the spark plug. This allowed the receiver to be blanked before the noise pulse arrived, which really improved the noise blanker performance. I was working on the design when marketing decided that it should tilt at other windmills. Only a few prototypes were built, were never patented or produced, and worked really quite well. Cheaper too. That was all just fine because cars were begining to use electronic ignition systems, which didn't have easily accessible ignition points. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#25
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How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
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. |
#26
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How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
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 |
#27
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How I would like to change the cell phone industry [was AM
Jeff Liebermann wrote:
Egads. I'm cleaning house and found a large box of 40 year old Motrash control heads and cables. Want some junk? Slacker...I tossed out all my old Moto stuff years ago. Last time I played with the Motorola line was around the Micors came out. i used a few of them for tower top UHF repeaters |
#28
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How I would like to change the cell phone industry [was AM
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. |
#29
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How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
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. |
#30
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How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
"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. |
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