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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]
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. http://en.wikipedia.org/wiki/Super_high_frequency I choose SHF frequencies because SHF seems to be the sweet spot between frequencies that are high-enough to rip through charged particles & provide large amounts of bandwidth, yet low-enough to be wireless and long-distance. At EHF and above, it starts to get into the IR range where long-distance wireless reception is not possible and atmospheric opacity begins to dominate. Equally important, SHF frequencies can efficiently transmit signals using extremely small transmitters. Longer wavelengths require larger transmitters. Obviously there are frequencies lower than SHF -- VHF and above -- that can easily penetrate charged particles [e.g. anything resembling the ionosphere or heliosphere]. However, lower-frequencies tend to result in less bandwidth, so it is better to use higher-frequencies when the application requires significant bandwidth. I choose AM because it requires less bandwidth than FM. In addition, AM tends to retain reception of rather weak signals, while FM "considers" such signals to be absent. |
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 Radium wrote:
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. Analog cell phones are going away. Cell phones already use frequencies in the 3 GHz region. You are an idiot. snip crap -- Jim Pennino Remove .spam.sux to reply. |
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 ... Cell phones already use frequencies in the 3 GHz region. Really? Which ones? I'm only aware of cell systems using 800, 900, 1800 and 1900 MHz. There are some (very few) multisystem phones that use all four of those ranges. |
How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
Radium hath wroth:
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. http://en.wikipedia.org/wiki/Super_high_frequency Maybe if the entire cellular infrastructure would move up to the LMDS 26-30GHz band, I might recover some of the money I sunk into an LMDS startup. Great idea. I like it. Of course, there are problems. Nobody makes an economical mm wave handset. There will probably need to be 8-10 times more cell sites built than are currently in use on 800/900 and 1800/1900MHz. Of course mm wave propagation is affected by just about everything, so it probably won't work indoors. No problem, just add more cell sites and repeaters. Of course you couldn't get away with the existing relatively low power output handsets and insipid gain antennas, so we'll just crank up the power and antenna gain on the handset and fry a few peoples brains. It's a small sacrifice to make so I watch TV on my cell phone. Equally important, SHF frequencies can efficiently transmit signals using extremely small transmitters. Longer wavelengths require larger transmitters. They do? I didn't know that. My 49MHz automobile alarm dongle isn't much larger than my 2400MHz USB wi-fi dongle. Are you sure the transmitter has to be bigger or were you thinking of the antenna? Obviously there are frequencies lower than SHF -- VHF and above -- that can easily penetrate charged particles [e.g. anything resembling the ionosphere or heliosphere]. I don't know of any wireless service provider that charges for particles. What are they charging and what's the stock symbol? I've always suspected that charged particles might be worth selling. However, lower-frequencies tend to result in less bandwidth, so it is better to use higher-frequencies when the application requires significant bandwidth. Hint: It doesn't matter what you're doing, there's never enough bandwidth available. If you provide XX MHz of available bandwidth, someone will immediately supply an application that required 10 times the available bandwidth. More simply, applications tend to fill up available bandwidth quite rapidly. I choose AM because it requires less bandwidth than FM. In addition, AM tends to retain reception of rather weak signals, while FM "considers" such signals to be absent. 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. This is fun. Kinda reminds me of some of the business plans I reviewed during the dot com boom. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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 Brenda Ann wrote:
wrote in message ... Cell phones already use frequencies in the 3 GHz region. Really? Which ones? I'm only aware of cell systems using 800, 900, 1800 and 1900 MHz. There are some (very few) multisystem phones that use all four of those ranges. Notice the word "region"? -- Jim Pennino Remove .spam.sux to reply. |
How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
On Jul 15, 2:14 pm, Jeff Liebermann wrote:
Radium hath wroth: 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. http://en.wikipedia.org/wiki/Super_high_frequency There will probably need to be 8-10 times more cell sites built than are currently in use on 800/900 and 1800/1900MHz. Why? Equally important, SHF frequencies can efficiently transmit signals using extremely small transmitters. Longer wavelengths require larger transmitters. They do? I didn't know that. My 49MHz automobile alarm dongle isn't much larger than my 2400MHz USB wi-fi dongle. Are you sure the transmitter has to be bigger or were you thinking of the antenna? Maybe the antenna. I choose AM because it requires less bandwidth than FM. In addition, AM tends to retain reception of rather weak signals, while FM "considers" such signals to be absent. I'll make it really simple for you. FM is "hi-fi", while AM is noisy "no-fi". 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. For decent quality, you gotta have FM. Nope. For decent quality sound you need audio that is uncompressed PCM [similar to CDs and WAVE files] with a sample rate of at least 44.1 KHz and a bit-resolution of at least 16-bit. Or the analog equivalent. |
How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
"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. Before making such a recommendation, I suggest you read up on a couple of topics. I'd suggest at least topics including: Near and far antenna performance. Path loss calculations Signal penetration Fading types Interleaving SAR Eb/No C/I Frequency stability and accuracy Component and radio design Modem methods Modulation methods. Vocoders Digital modulation General history of modulation techniques, AM, FM and digital Maybe others as they come up in your reading. and then study. Manufacturers and manufacturing history Company pioneering status IPR Regulatory compliance Government rule making processes (Nat'l and Intl) Spectrum use (bits / Hz) Standards setting Getting vendors to make components for you. Lead times Protecting customer's investment Security testing methods Engineering solutions requires you to keep you arms around all of this. If you are serious about your request and do not at least have a casual working knowledge of all these, you are wasting everyone's time. If your goal is to created fruitless discussion, you are right on track. No insult intended...just trying to tell it like it is. Bob F. |
How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
On Sun, 15 Jul 2007 14:45:06 -0700, Radium
wrote: On Jul 15, 2:14 pm, Jeff Liebermann wrote: Radium hath wroth: 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. http://en.wikipedia.org/wiki/Super_high_frequency There will probably need to be 8-10 times more cell sites built than are currently in use on 800/900 and 1800/1900MHz. Why? Equally important, SHF frequencies can efficiently transmit signals using extremely small transmitters. Longer wavelengths require larger transmitters. They do? I didn't know that. My 49MHz automobile alarm dongle isn't much larger than my 2400MHz USB wi-fi dongle. Are you sure the transmitter has to be bigger or were you thinking of the antenna? Maybe the antenna. I choose AM because it requires less bandwidth than FM. In addition, AM tends to retain reception of rather weak signals, while FM "considers" such signals to be absent. I'll make it really simple for you. FM is "hi-fi", while AM is noisy "no-fi". 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. For decent quality, you gotta have FM. Nope. For decent quality sound you need audio that is uncompressed PCM [similar to CDs and WAVE files] with a sample rate of at least 44.1 KHz and a bit-resolution of at least 16-bit. Or the analog equivalent. --- Wrong. -- JF |
How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
Radium hath wroth:
There will probably need to be 8-10 times more cell sites built than are currently in use on 800/900 and 1800/1900MHz. Why? For a given radio system, higher frequencies don't go as far as lower frequencies. You can see how it works by just plugging in different frequencies a "free space loss" calculator such as: http://www.terabeam.com/support/calculations/free-space-loss.php For every 6dB of additional path loss, your range is cut in half. Incidentally, this is not my idea or a conspiracy. Mother nature made it that way and we have to live with the physics. I'll make it really simple for you. FM is "hi-fi", while AM is noisy "no-fi". FM has too much hiss. FM has a limiter that eliminates all AM noise components. That's exactly the way the soon to be obsolete analog cell phones operate. If you're hearing hiss, then there's something broken in your FM stereo. FM signals are lost very easily. I have a lost and found for missing signals. It's called a spectrum analyzer. If the signal wanders, I can usually find it. Not a problem. AM tends to retain reception of a signals even when this signal is extremely weak. Not really. If you really want weak signal reception, I suggest you look into SSB (scientific set back) modulation. Half the bandwidth gives you twice the sensitivity. 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. Nope. All FM receivers have a squelch to mute the receiver when there's not enough signal to make it worth listening. The squelch is much more efficient with FM than an AGC operated squelch for AM. Anyway, if someone calls with me on my cell phone with a crummy signal, I don't want to talk to them and I usually ask them to call me back when in a better area. The problem with AM audio is that the ultimate signal to noise ratio isn't very good. AM is noisy at any signal strength. The noise never really goes away. On the other foot, FM is noisy with very weak signals, but becomes very quiet once the limiter starts to work. That's why FM is preferred for music and why analog AM broadcasting sounds marginal at any signal level. 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. If your FM radio has a deafening hiss, you're probably not tuned to any station. Try listening to a station instead of between stations. If it has an AFC, turn it on. There may also be some kind of malfunction in your hi-fi as you should not be hearing any hiss when tuned to a station. For decent quality, you gotta have FM. Nope. For decent quality sound you need audio that is uncompressed PCM [similar to CDs and WAVE files] with a sample rate of at least 44.1 KHz and a bit-resolution of at least 16-bit. Or the analog equivalent. I thought you didn't like digital? You only gave me a choice of AM or FM. Now, you want digital. Well, digital is what today's cell phones use mostly to maximize spectrum efficiency. With compression and proper coding, you can pickup quite a bit of efficiency, at the expense of sounding like you're gargling ball bearings. Not too bad a tradeoff for voice. Really awful for music. Fortunately, none of the broadcasters or cellular carriers use raw CD data, mostly because it's not compressed. So, are you ready to go public with your idea? When's the IPO? -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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 ... 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). |
How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
On Jul 15, 4:30 pm, Jeff Liebermann wrote:
Radium hath wroth: The problem with AM audio is that the ultimate signal to noise ratio isn't very good. AM is noisy at any signal strength. The noise never really goes away. On the other foot, FM is noisy with very weak signals, but becomes very quiet once the limiter starts to work. That's why FM is preferred for music and why analog AM broadcasting sounds marginal at any signal level. AFAIK, the main issue with AM is that it is much more vulnerable to magnetic disruptions than FM. 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. 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. Nope. For decent quality sound you need audio that is uncompressed PCM [similar to CDs and WAVE files] with a sample rate of at least 44.1 KHz and a bit-resolution of at least 16-bit. Or the analog equivalent. I thought you didn't like digital? You only gave me a choice of AM or FM. Now, you want digital. It depends, if I can find the analog-equivalent of 44.1 KHz-sample- rate, 16-bit-resolution digital audio, that just as good. If I a limited to only AM or FM for analog audio, I choose AM because I like the sounds generated by solar prominences and other RF magnetic disruptions. Ironically, for video, I prefer FM. Yup, video signals on FM carriers instead of AM carrier. The Y-luminance signal should be broadcasted on an FM carrier. That's the analog video I like. With compression and proper coding, you can pickup quite a bit of efficiency, at the expense of sounding like you're gargling ball bearings. Disgusting! I hate most forms of digital audio compression. For me, either keep it uncompressed or use WMA compression. All non-WMA digital audio compressions below 320 kbps sound like stinky human fart. Or an angry infant foaming at the mouth. Not too bad a tradeoff for voice. Really awful for music. Awful for both. The only digital audio compression I like is WMA. The sounds resulting from WMA compression sort of make me think of those RF electronic telecommunication devices used in The Bourne Identity. That movie features some really awesome devices that make those interesting sounds - for example, when the main character is getting his hand screened. I also associated these sounds with the electronic telecommunication devices used by the Soviet Union. Soviet Union has got some really psychedelic sounds in their electronics. You know, those fancy dial-up modems tones? Fortunately, none of the broadcasters or cellular carriers use raw CD data, mostly because it's not compressed. All digital audio compression formats other than WMA, stink badly!! Here are my rules for digital audio: A. Whether compressed or not, the audio must be monaural and with a sample-rate of at least 44.1 kHz. B. The only compression allowed is WMA. No other compression format is permitted. C. In its uncompressed form, the audio must have a bit-resolution of at least 16-bit D. If compression is used, then the sample-rate of the compressed and the uncompressed version of the audio must be the same. E. If compression is used, the only thing that should be decreased is the bit-resolution. The sample-rate must remain unchanged Let's say a song that was originally recorded in stereo is given to me. The song must to be converted to mono* via the following steps: 1. Record audio from CD [or other stereo audio source] into Wavelab, Adobe Audition [or other audio software] into a file. For simplicity let's call this file "Track1.wav" 2. Make a copy of Track1.wav and save the copy as "Track1B.wav" 3. Open Track1.wav and reduce the gain of its audio by 77.5% 4. Convert Track1.wav to monaural audio 5. Save Track.1 6. Open Track1B.wav and reduce its audio gain by 50% 7. Invert the phase of the left channel of Track1B.wav 8. Convert Track1B.wav to mono 9. Save Track1B.wav 10. Create a new stereo wave file whose bit-resolution is 16-bit and sample rate is 44.1 kHz. For simplicity let's call this file "untitled.wav" 11. Copy and paste the audio of Track1.wav into the left channel of untitled.wav 12. Copy and paste the audio of Track1B.wave into the right channel of untitled.wav 13. Convert untitled.wav to mono 14. Save untitled.wav *Songs that were originally-recorded in stereo need to be converted to mono via the above 14 steps because different sounds are recorded differently in the L and R channels. The audio that is originally panned to the center is significantly louder than the audio whose phase is different in the left & right channels. This is why I reduce the loudness of non-inverted stereo audio file by 77.5% [before converting it to mono]. In the stereo file whose left channel has its phase inverted, I decrease the loudness only by 50% and then convert it to mono. Usually -- the lead vocals, bass, and percussion are recorded identically in both the left and right channels. The piano, chorus, guitar, and synth pads are usually recorded differently in the left and right channel. |
How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
"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 |
How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
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. The main issue with AM is susceptibility to pulsed noise, as found in motors, fans, auto engines, and computahs. FM doesn't have as bad a problem because the limiter in the receiver clips everything to the same level, thus reducing the effect. 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. However, the microwave oven may have a fan or CPU that runs the display, that belches garbage at 1MHz. I just tried mine and there's a tiny bit of buzz coming from the display section when I shove an AM radio right up to the display. If that's what you're hearing, I would test it with a different microwave oven. If only yours has the problem, I suggest you consider a replacement. 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. (chomp...) Sorry, my time is up. Please insert $0.25 for the next 3 minutes. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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 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. The main issue with AM is susceptibility to pulsed noise, as found in motors, fans, auto engines, and computahs. FM doesn't have as bad a problem because the limiter in the receiver clips everything to the same level, thus reducing the effect. 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. However, the microwave oven may have a fan or CPU that runs the display, that belches garbage at 1MHz. I just tried mine and there's a tiny bit of buzz coming from the display section when I shove an AM radio right up to the display. If that's what you're hearing, I would test it with a different microwave oven. If only yours has the problem, I suggest you consider a replacement. 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. (chomp...) Sorry, my time is up. Please insert $0.25 for the next 3 minutes. Don't tell him about whistlers. -- Jim Pennino Remove .spam.sux to reply. |
How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
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 |
How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
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 |
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 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. |
How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
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 |
How I would like to change the cell phone industry [was AM
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. |
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. |
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. |
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. |
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 |
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. |
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 |
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 |
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. |
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. |
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. |
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: 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 The local hams still have ancient junk pretending to be repeaters and such. http://www.LearnByDestroying.com/k6bj/ I built most of it out of Micor mobiles and base stations. Since the Micor stake pin connectors are chronically intermittent, there's a large rubber hammer in each rack to bang on each radio to reseat the connectors. Since no sane person keeps such old parts around, I get to stock old radios and pieces at my house. When the local comm shop cleaned out their ancient Motorola parts pile, I ended up with most of their old parts. I think it's time for a general purge, which means either eBay or the scrap metal recyclers. What I find amusing is that many police and fire departments rebuild antique or vintage police cars and engines. They eventually want a genuine Motorola twin coffin or 80D radio for the vehicle. I've supplied about 4 of these radios (working) for various projects. The first step is to spray the crumbling rubber insulated wiring with clear acrylic to prevent further deterioration. Getting the radios working is fairly easy as I have all the old test sets and some docs. The fun part for me is watching the current crop of comm techs trying to install the monster case in the vehicle. What do I do with all this big fat cable is usually the first question. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Gas Tube Noise Source WAS: How I would like to change...
Jeff Liebermann wrote:
snip I have a fluorescent lamp calibrated noise source that's quite noisy well into the GHz range. snip 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. I was quite excited by the acquisition of a CATV distrib. amp as a giveaway at a local hamfest earlier this spring; I modified it to accept external power and use BNC connectors and produced a hand- drawn schematic which I will 'capture' when time permits and post together with photos. I have used it as a front end to a freq. counter and an oscilloscope and without it I could not have completed several projects. These units are so handy it is a wonder that (at least on the Web) there has been little mention of their experimental uses. BTW, which of the numerous newsgroups in this miserably cross-posted thread do you regularly read? Regards, Michael |
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 Bob Myers wrote:
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. But will such a scheme work with bagels and, more importantly, only toast one side? -- Jim Pennino Remove .spam.sux to reply. |
How I would like to change the cell phone industry [was AM
Bob Myers wrote:
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. If it will handle full grown trolls, I want the first ione! How long before Radium would be golden brown, and ready to feed to the hogs? ;-) -- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida |
How I would like to change the cell phone industry [was AM
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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]
"Radium" wrote in message oups.com... | On Jul 15, 6:58 pm, Jeff Liebermann wrote: | | Radium hath wroth: | | The AM audio cause by lightning is so boring. | 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. | | One thing that I do like are the sharp sawtooth wave patterns that | show up on FM video receivers whenever lightning strikes. FM video | receivers receive Y [luminance] signals present on FM radio waves. | Electrical disturbances affect the FM video receiver causing those | beautifaul zapping and buzzing sawtooth patterns on the screen. The only FM on standard TV is the audio. Video is vestigial sideband AM. BTW my grand daughter had that figured out by the time she was 12 y.o. |
How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
On Jul 16, 9:15 am, DTC wrote:
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. FM audio is boring -- no entertaining high-pitched tones from solar prominences which would definitely be heard on AM audio. OTOH, AM video is boring. FM video is better. As I said before, the Y [luminance] signal should be carried on an FM wave rather than an AM wave. Analog radio-frequency audio devices should use AM. Analog radio-frequency video devices should use FM. |
How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
On Jul 15, 6:58 pm, Jeff Liebermann wrote:
Radium hath wroth: The AM audio cause by lightning is so boring. 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. One thing that I do like are the sharp sawtooth wave patterns that show up on FM video receivers whenever lightning strikes. FM video receivers receive Y [luminance] signals present on FM radio waves. Electrical disturbances affect the FM video receiver causing those beautifaul zapping and buzzing sawtooth patterns on the screen. |
How I would like to change the cell phone industry [was AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency]
"NotMe" wrote in message ... "Radium" wrote in message oups.com... | On Jul 15, 6:58 pm, Jeff Liebermann wrote: | | Radium hath wroth: | | The AM audio cause by lightning is so boring. | 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. | | One thing that I do like are the sharp sawtooth wave patterns that | show up on FM video receivers whenever lightning strikes. FM video | receivers receive Y [luminance] signals present on FM radio waves. | Electrical disturbances affect the FM video receiver causing those | beautifaul zapping and buzzing sawtooth patterns on the screen. The only FM on standard TV is the audio. Video is vestigial sideband AM. BTW my grand daughter had that figured out by the time she was 12 y.o. Analog satellite still uses FM, but there is very little of that left. 30MHz wide channels. Think there used to be one version of SECAM (in France, IIRC) that used FM video. That's gone now, too. |
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 ... Have you ever attended a meeting or event about something you really don't care about? The lady friend has dragged me to horse shows, dog shows, cat shows, and various cultural events, where it was a major accomplishment for me to stay awake. Yet to her, it was the highlight of excitement and of great interest. In other words, science and technology may be interesting to you and I, but to many, it's just a big boring waste of their time. Oh, sure, and I couldn't agree more. I place the blame for that squarely on our education system, which - unless you have amazingly good luck in getting the right teacher - will present "science" as an incredibly dull collection of arcane facts and formulas to be memorized, and not an interesting, exciting process full of wonders. The root of that, of course, is just that the "science" teachers most often don't really know what "science" is all about in the first place. Wrong. Science fiction has mutated into social adventure, space opera, and historical fantasy. I haven't seen any really technical science fiction in many years. Spider Robinson. Joe Haldeman. Larry Niven. Jerry Pournelle. Ben Bova. Greg Egan. Stephen Baxter. Arthur C. Clarke, who, thank the FSM, is still with us and writing. Sure, there's an AWFUL lot of crap out there - SF, like everything else, obey's Sturgeon's Law - but the good stuff is still being written. You just have to look for it. Bob M. |
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