Author Archive
1920 film: How the Telephone Talks (A Silent Film)
November 9th, 2013 | 
Author: This is for you vintage science film buffs: here is a circa 1920 film: How the Telephone Talks (A Silent Film).
This is an educational film from 1920 that explained the “modern” telephone. The concepts are still relevant to today’s modern versions, including the cell phone, which is both radio and telephone.
From Wiki:
A telephone, or phone, is a telecommunications device that permits two or more users to conduct a conversation when they are not in the same vicinity of each other to be heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals suitable for transmission via cables or other transmission media over long distances, and replays such signals simultaneously in audible form to its user. The word telephone has been adapted into the vocabulary of many languages. It is derived from the Greek: τῆλε, tēle, far and φωνή, phōnē, voice, together meaning distant voice.
First patented in 1876 by Alexander Graham Bell and further developed by many others, the telephone was the first device in history that enabled people to talk directly with each other across large distances. Telephones became rapidly indispensable to businesses, government, and households, and are today some of the most widely used small appliances.
The essential elements of a telephone are a microphone (transmitter) to speak into and an earphone (receiver) which reproduces the voice of the distant person. In addition, most telephones contain a ringer which produces a sound to announce an incoming telephone call, and a dial used to enter a telephone number when initiating a call to another telephone. Until approximately the 1970s most telephones used a rotary dial, which was superseded by the modern Touch-Tone push-button dial, first introduced by AT&T in 1963. The receiver and transmitter are usually built into a handset which is held up to the ear and mouth during conversation. The dial may be located either on the handset, or on a base unit to which the handset is connected by a cord containing wires. The transmitter converts the sound waves to electrical signals which are sent through the telephone network to the receiving phone. The receiving telephone converts the signals into audible sound in the receiver, or sometimes a loudspeaker. Telephones are a duplex communications medium, meaning they allow the people on both ends to talk simultaneously.
A landline telephone is connected by a pair of wires to the telephone network, while a mobile phone, such as a cellular phone, is portable and communicates with the telephone network by radio transmissions. A cordless telephone has a portable handset which communicates by radio transmission with the handset base station which is connected by wire to the telephone network.
The telephone network, consisting of a worldwide net of telephone lines, fiber optic cables, microwave transmission, cellular networks, communications satellites, and undersea telephone cables connected by switching centers, allows any telephone in the world to communicate with any other. Each telephone line has an identifying number called its telephone number. To initiate a telephone call the user enters the other telephone’s number into a numeric keypad on the phone.
Although originally designed for simple voice communications, most modern telephones have many additional capabilities. They may be able to record spoken messages, send and receive text messages, take and display photographs or video, play music, and surf the Internet. A current trend is phones that integrate all mobile communication and computing needs; these are called smartphones.
Solar Plasma Filament Eruption – The Sun – November 6,7 2013
The Sun currently is active, with powerful, complex magnetic structures that have formed a healthy number of sunspots. We are seeing a fair number of x-ray flares, which push the 10.7-cm flux higher than we’ve seen in a while.
Sunspots and flares means better propagation in general, especially on the higher frequencies of the shortwave spectrum. While a flare can cause a short period of “blackout” conditions (especially on the lower frequencies) on the sunlit side of the Earth, such activity is part of the positive activity that ionizes the F-region, providing for DX.
Here’s a movie of one such flare and the release of solar plasma, a release known as a coronal mass ejection (CME): At about midnight, UTC, on 6 November 2013, a moderately-strong M-class flare erupted, with a “beautiful” CME: http://g.nw7us.us/18a0QvI
(Source: SOHO/SDO/NASA)
We will see continued flare activity over the weekend, so expect great conditions on the HF bands, with momentary blackouts. Keep up to the minute on space weather at http://SunSpotWatch.com
73 – de NW7US
Propagation Columnist, CQ Communications Magazine, Popular Communications Magazine
http://NW7US.us
Expect Uptick in HF Propagation Even on 10m, This Week
New sunspot region, NOAA Active Sunspot Region Nr. 11890, far left on the solar disc, will produce flares, this week.
The Sun continues to produce sunspots, and this week looks active, too. Expect another uptick of activity on higher HF bands such as 10 meters, as a “new” sunspot region has now rotated into full view. It has a complex magnetic structure, so it could produce moderate and maybe strong x-ray flares. We expect flaring activity to pick up, as a result.
With all of the recent activity, and the continued train of spots, right now, it certainly appears to be a sign of a “second” peak in the cycle. Most cycles exhibit such double peaks. Is this one of them in this current Sunspot Cycle 24?
Enjoy the DX!
73 de NW7US (Your CQ Magazine and Popular Communications Magazine propagation columnist)
A Short Journey Down History Lane: 1939 New Zealand Radio
Shortwave radio history – communications in and out of New Zealand in 1939. This history is rich with adventure and successes that are profound. Our modern communications all stems from this historic work…
This is a short film about the romance of the radiotelegraph service that utilized the high frequency spectrum known as “shortwave” (from 3 MHz up to 30 MHz) as well as the longwave and medium frequency spectrum (below 3 MHz). This is a short film about communication to and from New Zealand on these shortwaves, using Morse code (eventually, using CW modulation). This film is a 1939 Government film scanned to 2K from a 16mm combined B/W reduction print.
The Sun is flipping out!
Every approximately eleven years, the Sun produces a “cycle” of sunspot activity. At the very lowest point in this cycle, there are few, if any, sunspots observed. Such a lack of sunspots can last for weeks. During the peak of the sunspot cycle, there can be a multitude of sunspots, ranging in size. This cycle is known as the sunspot cycle. It is caused, in part, by the magnetic activity within the Sun. Every eleven years, the Sun’s magnetic polarity flips–the north becomes south, the south becomes north. This is normal. Every twenty two years, then, the Sun goes through one full magnetic flip cycle. The flipping seems to coincide with the timing of solar cycle maxima. When it flips, we know about where we are in the eleven-year cycle. The magnetic polarity of the Sun appears to be in the process of reversing, over the next few months. If so, then we’ve pretty much reached the sunspot cycle maxima for Cycle 24. Observers note that this cycle is quite a bit less active than the last few eleven-year cycles.
A video that talks about this reversal is here:
The flipping of the Sun’s magnetic poles: Sunspot Cycle 24
More information on the Sun and the cycle, radio propagation, and related topics:
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Coronal Mass Ejection (CME) on 2013/09/29
A magnificent eruption ejected a massive cloud of solar plasma out away from the Sun, into interplanetary space on September 29th (2013/09/29). A long filament of plasma hovered above the photosphere, captured by the magnetism in the Sun’s northern hemisphere. Then, it erupted in spectacular energy as seen by the Solar Dynamics Observatory, and by Stereo and SOHO spacecraft. This plasma eruption produced a stunningly beautiful coronal mass ejection (CME).
Coronal mass ejections are often associated with solar activity such as solar flares, but a causal relationship has not been established. A coronal mass ejection is also produced when a plasma filament (or prominence) breaks away from the magnetic clutch of the Sun, escaping the gravitational pull. While many plasma ejections originate from active regions on the Sun’s surface, such as groupings of sunspots associated with frequent flares, any plasma formation could break away. Near solar maxima, the Sun produces about three CMEs every day, whereas near solar minima, there is about one CME every five days or even less frequently.
When a CME passes Earth (not all CMEs are directed toward the Earth), it could cause geomagnetic disturbances, triggering aurora and causing disruption of shortwave radio communications.
Although this CME was not aimed at Earth, it passed by the Earth with a glancing blow from the plasma cloud on October 2-3 2013. This caused a geomagnetic storm (minor level), which lowered the Maximum Usable Frequency (MUF) over many ionospheric radio-wave propagation paths on shortwave radio. This lowing of the MUF is often regarded as a
degradation of shortwave radio conditions. Some aurora is also produced, though this event did not cause much significant aurora.
Here’s a video showing the magnificent plasma eruption and CME:
Credit: SOHO/Stereo/SDO/NASA
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Aurora Watch: http://Aurora.SunSpotWatch.com
