Geoff Fors checks in again with more recollections of the communal telephone service he described in his China article:

Hi Tom: I thought I would pass on further details about the Chinese telephone system as it was in the 1970's, at least in Shanghai. You recall the round brick hut near where I lived, which I mentioned earlier. I asked my friends who lived through that era exactly how the system worked. It seems the huts were strategically located and contained a PA system with loudspeakers on the roof. When a call came in, the attendant would get on the PA mike and broadcast for a three block radius: "so-and-so of building # 433, apartment 201, you have a phone call !" Then so-and-so would come running and get his message, and presumably return the call, whereupon the attendant at a distant hut at the other end would then duplicate the process, until someone broke the loop by actually being present when the call came in. One thing that occurred to me was what happened after dark, that is, how could you sleep with that speaker blasting announcements all night ? It was then explained that the hut closed after a certain hour, maybe at dinnertime, and in general, so few people got calls that it wasn't that much a source of noise-pollution even with one phone hut per 5000 homes. For gossips, it must have been a dream come true. Get a call, and everyone in the entire neighborhood knows it. Geoff

| Permalink | Comments (0)

It's accepted that in 1901 Marconi received the first trans-Atlantic radio signal, the letter "S", three clicks, tapped out in Morse code. Don Kimberlin now questions that accomplishment in a well written and researched article, "Investigating Radio's Roots: What Did Marconi Hear? The World's Most Heralded Radio Failure." The article is in .pdf form:
http://www.oldradio.com/archives/jurassic/marconi2.pdf (external link)

There's do doubt Marconi's team transmitted a single "S" from Poldhu in Cornwall, near Land's End. But did Marconi actually receive it? Or did he and the sole witness to the event hear something else? Something they mistook for the signal? I've written many times how difficult it is to determine radio firsts; Marconi's claim now proves equally hard to establish. Time to rewrite the history books. Again.

Update. In response to my question to Don, How could an experienced operator like Marconi confuse telegraph dashes for lightning produced static?, Kimberlin responds:

Tom:

How did Marconi might mistake lightning for his desired signals? The key lies in the sound he wanted to hear.

Perhaps I didn't speak enough to the point of the way they had tuned the Poldhu spark transmiter. At the time, their financial strain was such that in order to minimize stress on the Poldhu transmitter, they had reduced the duty cycle of the spark to such a short period that each "key down" on the transmitter produced only a very short "click" of transmission, not the "buzz" we are accustomed to expect from a Type B emission. That way, heating and possible damange while producing maximum power at Poldhu was reduced.

Certainly, Marconi had heard lighting before, but here he was expecting merely a train of 3 clicks in an earphone. They could as easily have come from a natural source as from his transmitter.

I think what is key here is to have some understanding of just how much more favorable a south-north equatorial transmission path is than an east-west one. I may be more sensitive that difference than most people who are not HF propagation specialists, merely because I worked in AT&T's HF radio plant at Fort Lauderdale, FL -- a place that ran largely north-south paths in the equatorial region. It meant we could run commerciallly suitable links most any day of most any part of the solar cycle - high or low - while the AT&T plants at New York and San Francisco often had days of downtime, particularly in lows of the solar cycle.

And, December 12, 1901 was the lowest of low -a day of absolutely zero sunspots.

Since writing the article, it has crossed my mind there could have been a minor geomagnetic storm, which would be highly unlikely, and I can't rule out one of the annual meteor showers, and I intend to correspond with an expert or two on those. I rather expect their opinion will be neither of those as a cause on 12/12/1901.

Don Kimberlin

| Permalink | Comments (0)

A privateline.com/TelecomWriting.com reader asks:

I'm confused. How in GSM can we fit a gross bit rate of 270 Kbps in the 200 KHz channel on the air interface? GSM uses Gaussian-filtered Minimum Shift Keying or GMSK. That technology has a spectral efficiency of 1 bit/symbol/Hz. Does that mean we use1 bit per symbol and not more?

Professor R.C. Levine responds:

I am writing this quickly and may not remember all the numbers exactly, so if you find other numbers in other source documents, I may have the numbers wrong.

GMSK modulation has a "spectral efficiency" of APPROXIMATELY 1 bit per symbol or 1 bit per hertz of bandwidth. The word "approximately" is used because there are several different ways to measure the bandwidth of a signal.

The method used for GMSK signals in GSM is to find the bandwidth that contains about 99% of the radio signal power. GMSK was developed specifically for GSM by the COST (Council on Science and Technology, a scientific advisory group funded by CCITT and later ETSI). GMSK is a type of minimum frequency shift (MFS) modulation that achieves an approximately optimum compromise . . . .---> (continues here within the GSM article)

| Permalink | Comments (0)

WISPCON starts today in Dallas. Think about attending if you're near. WISPCON stands for Wireless Internet Service Providers Conference. Of course. Here's a link to them. (external link)

http://www.wispcon.info/US/WISPCON-IV/WISPCON-IV.htm

| Permalink | Comments (0)

Number portability means keeping your old telephone number when you pick a new telephone company. That hasn't been possible with mobile phones before but it will soon become law in the United States. Starting on November 24, 2003, wireless companies in the 100 top American markets must maintain your present number, even if you switch carriers. It's also required that you can get your home telephone number transferred to your wireless. Background information is here:

http://wireless.fcc.gov/wlnp/ (external link)

Wireless carriers will delay implementing it but eventually portability will become standard practice. It's estimated that up to 40% of wireless users may switch carriers in portability's first year. Will portability improve cost, service, and coverage? Perhaps. If customers can change providers as easily as their long distance company, wireless companies might try harder to keep people happy. This is an optimistic view.

Besides some effort to improve, wireless companies will focus on writing long term contracts, with two years becoming the norm. And they'll keep making wireless plans so confusing that you won't be able to easily compare different carriers. Don't sign a contract until after the 24th. Cellular radio is wonderful technology but the way it is sold and marketed is miserable. A shame.

Consumers' Union has excellent information on this subject, including ways to protest delaying tactics to Congress:

http://www.consumersunion.org/

campaigns/escapecellhell/ (external link)

More on this on my cellular plan page.

| Permalink | Comments (0)

University of Alberta scientists announced yesterday that water produces electricity when pumped at pressure through tiny microchannels. The water does not spin a turbine or in any way use mechanical or chemical energy to produce power. Electricity is drawn instead from "the work done to push the liquid through the channel." Fascinating reading but I am not a scientist and I am still baffled by how this process works. I'll keep reading and then I'll let you know if I come up with a simple explanation. Here's something from the press release and two links:

"A new way of generating electricity from flowing water could mean that in the future you will never have to charge up your mobile phone again. Instead of a normal battery, mobile phones could be fitted with a battery that uses water -- you just need to pressurise it regularly."

"Research published today by the Institute of Physics journal, Journal of Micromechanics and Microengineering, reveals a new method of generating electric power by harnessing the natural electrokinetic properties of a liquid such as ordinary tap water when it is pumped through tiny microchannels. The research team from the University of Alberta, Edmonton, Canada, have created a new source of clean non-polluting electric power with a variety of possible uses, ranging from powering small electronic devices to contributing to a national power grid."

"The research was led by Professor Daniel Kwok and Professor Larry Kostiuk from the University of Alberta. The project started as a simple conversation between Kostiuk, a thermodynamicist, and Kwok, a nanofabrication researcher. With the assistance of two graduate students, who benefited first-hand from the teachings of their supervisors as well as contributed to the work, the team was able to illuminate a real light bulb by exploiting the coupling between electrokinetic phenomena and the hydrodynamics of liquid flow."

http://www.iop.org/EJ/news/-topic=632/journal/JMM (external link)

http://www.engineering.ualberta.ca/ (external link)

| Permalink | Comments (0)

While telecom races forward I am stuck in the past, tending to the 340+ existing pages on this site. I've been fixing dead links, updating information, and placing small ads here and there. It would be nice to do more original writing but I'm unable to put much time into that when everything I've done so far needs another look. Updating one page can take from five to fifteen minutes. Sometimes more. A good day means I might finish 16 pages. But, depending on what I discover in the next few days, new information or ideas, I might be back to those recently finished pages to polish them up even more. Feels like I'm drowning. If I got a corporate sponsor like Lucent I could pull off the ads and work on the site full time. Right now, though, it is strictly a hobby and I am spending as much time as I can on it, not the time I want.

| Permalink | Comments (0)

(This information relates to my cellular site leasing information page.)

Where can you put a communications tower? It depends on many things, from public agencies to people. Mark says, "Local zoning laws do apply. There are some things that local zoning can't do, like ban towers altogether from a particular jurisdiction, but they can regulate where the towers go, and they can place restrictions on the manner of construction, setbacks, aesthetic issues, and a host of other things. In the case of a subdivision which my have CC&Rs [codes, covenants and restrictions, ed.] or deed restrictions, these will likely be enforceable. Don't sign anything that is not subject to local zoning approval. As always, consult a lawyer for legal advice. Also, don't forget the neighbors. You could find anything from support to indifference to vicious attacks."

Here's a good local planning article:

http://www.plannersweb.com/articles/cam128.html (external link)

And here's an excellent page on negotiating contracts with wireless carriers:

http://www.dcba.org/brief/octissue/2002/art21002.htm#top (external link)

| Permalink | Comments (0)

Sam Omastsye reports in October 13th's RCR Wireless News (external link, now dead) that the ceremonial first American AMPS cellular call was made on Oct. 13, 1983 at Soldier's Field in Chicago. AMPS had been working since 1978 but not in full commercial service. The October date marks when the general public could start using cellular. Omastsye quotes Scott Erickson, who attended the event, as saying Bob Barnett, Ameritech Mobile's president, placed the first ceremonial call. It went to Alexander Graham Bell's grandson in Berlin, Germany. I'm trying to find out if this was Edwin Grosvenor, an excellent Bell biographer. Chicago Cubs announcer, Jack Brickhouse, announced that first call to the crowd on a cold, bright day in a ceremony including balloons and a band.

| Permalink | Comments (0)

I've written that the telephone is an electrical instrument. Electricity powers the phone and it carries or conveys your voice from the telephone to the local switch. Not exactly. Electricity on two wires flows or is conveyed to work the phone itself: to operate the keypad, to make it ring. But electricity does not carry the voice.

Electric current doesn't convey the voice, sound simply varies that current. It's these electrical variations, analogs of the acoustic pressure originally spoken into the microphone, that represent voice. We have two different points here: about the current itself, and, about how that current is altered.

To sum up, electricity is indeed conveyed to the phone, whereupon 1) the current operates the telephone and 2) the current is varied by the voice to communicate. The diagram linked below makes this far more simple than a word description.

The telephone is an electrical instrument. Speaking into the handset's transmitter or microphone makes its diaphragm vibrate. This varies the electric current, causing the receiver's diaphragm to vibrate. This duplicates the original sound. Take a look at this image to make this point much clear.

| Permalink | Comments (0)

I just read the definition of the telephone in one of your articles and it made me think of something, Why is a microphone called a microphone if its not very small?!?

Good question. The Oxford Universal Dictionary says the word dates back to 1683. Who would have guessed that ? It further says that microphone derives from two Greek words and refers to an instrument used to magnify small sounds. Micro in microphone, therefore, doesn't mean the size of the instrument, rather the ability of that instrument to augment weak sounds. Thanks for the query, best, Tom Farley

| Permalink | Comments (0)

Four wire circuits provides the best quality transmission because transmit and receive paths are separated. Huh? Difficult to explain with words but easy to depict with a photograph, the four wire principle is illustrated with the garishly colored photograph below:

| Permalink | Comments (0)

Hi Tom,

I've gone thru a lot of sites trying to find a suitable learning Material on Digital stuff for a long time. I worked for Telecom company in Vanuatu South West Pacific (TVL) When I left school I was the Only unlucky one attending a Telecom Technical school in Fiji where the Instructor was a Line Plant technician and was absent 75% of the time, I really have not grasp the basics of radio communication. Since 1989 till this day when I come across you Web page. I can not express our much I feel. Its a feeling of achievement even though I still don't read thru much yet Thanks. I owe you for say....A beginning of a New Start in this Techno Era. Congratulation on your Will to Share your Knowledge which I believe you invested a lot on and yet you share it with the unfortunate once like me.

A lot of Thanks

A reader (name with held)

"Formerly called the New Hebrides, Vanuatu is a Y-shaped chain of 322 tropical islands of volcanic origin situated in Melanesia to the east of Australia. . . "

| Permalink | Comments (0)

The photo caption in your telephone history series (internal link) is incorrect. The large electronic tube is not the single "500 kilowatt valve." It was one of FIFTY-FOUR ten kilowatt tubes operable in parallel to form the transmitter at Hillmorton, near Rugby, in England. When I finish this note, I'll try to find the web link to a local web page from there that has some of the description of the site. That plant exists today and is still on the air, its 8 towers of 800 odd feet being visible for miles around.

The giant transmitter is actually ten radio amplifiers of 100 kilowatts input, 54 kilowatts output each. That, if used together, is called by some one million Watts, based on input; by others, 500 kilowatts or 540 kilowatts based on output. In fact, other than for initial testing, all ten amplifiers were never tied together. Nine of them are used in parallel, excited from a source of the Very Low Frequency of 16.7 kilohertz. with the callsign GBR - which might stand for Great Britain Radio or Great Britain Rugby, or some ways in England say, "Great Bloody Radio."

The original purpose of GBR was to be able to send a telegraphic message to anywhere in the old British Empire at any day or time. It evolved into marine radio use, and since the Cold War, has been used to transmit telegraph to England's nuclear submarines, in the same way the US Navy has several VLF stations for the US subs. The tenth 100 kw in/54 kw out amplifier was the bit used for that first transatlantic radiotelephone link in 1927. It was excited at 60 kilohertz with a single sideband speech exciter to work with its AT&T mate in the States. The AT&T reciever ultimately wound up at Houlton, Maine (which was used in later years as AT&T's Telstar satellite station site), and the Deal Beach transmitter on 55 kilohertz was ultimately replaced with one at RCA's huge transmtting plant at Rocky Point, Long Island. The callsign for the British end was GBT, obviously for Great Britain Telephone or such. I have some docments and the callsigns of the US end somewhere in the clutter here...

When HF (shortwave) radio came into practical use, the VLF link was primarily used as the "backup." Even when the first submarine telephone cable was laid across the Atlantic in 1957, the several shortwave links were retired, but the Rugby-Rocky Point pair were actually kept on the air (but idle) as the final backup - actually in case of nuclear attack that would potentially make render both cables and shortwave useless. It wasn't till there were several cables and satellites in use that the 60 kHz/55 kHz link was retired. In England, the 60 kHz operation's callsign was changed to MSF, and it became England's standard time and frequency reference transmitter, which it is to this day. Over the years, the 1927 transmitters have certainly been replaced, but the British Post Office maintains a security cloak over what the GBR transmitter is today. They have told that the MSF transmitter has been replaced a couple of times, and we can certainly expect similar change has been made to GBR. Here's the web page, which isn't that well written, for GBR.

http://62.32.51.17:8033/Radio_masts/ (external link) May now be dead

There's a whole lot more to the early days of telecommunications. I have written a number of vignettes of the monsters of early radio, which I call "Jurassic Telecommunications." By and large, like the dinosaurs, it grew from cricket chirps into beasts of 100 or even 300 kilowatts, and the final bit were a few megawatt monsters like GBR. One of the more interesting ones is the French megawatt spark monster that Blackjack Pershing ordered in WWI, at a Bordeaux location called Croix d'Hins. It was intended as a backup link across the Atlantic in case the Germans cut the transatlantic telegraph cables. Its callsign was merely LY and operated on VLF of 12.7 kHz. It didn't last long after the war, because when radio began to develop, it was found to cause so much interference that it had to be abandoned! Here's a page about it:

http://www.radio-ecouteur.net/croixhins.htm (external link, now dead)

And, here are a couple of links about a third monster, Alexanderson's Alternator, of which one plant is still maintained at Grimeton, Sweden, callsign SAQ on 17.2 kHz:

http://www.telemuseum.se/historia/alex/ (external link, now dead)

1.html http://www.telemuseum.se/grimeton/defaulte.html (link now dead)

There were (and indeed, still are) many "footprints of the dinosaurs" of radio among us. Just last month, I was in Florida finding the concrete tower base of the first - ever AM broadcast "directional antenna" in the world. I hope you find all this interesting. I add to the database as I can. You can see some of it in the Archives section of: www.oldradio.com (external link)

Cheers, Don Chamberlin

| Permalink | Comments (0)