Antique radio

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An antique radio is a billable radio receiver because of its age and scarcity. Although there are no precise criteria for antique radios, usually 50-year-old vacuum tubes or World War II, and pre-1960 transistor sets will qualify.

Video Antique radio

Antique radio type

Morse recipient

The first radio receiver uses a coherer and sounding board, and is only capable of receiving CW wave (CW) transmissions, encoded with Morse code (wireless telegraph). Then the cordless phone | transmission and acceptance of speech became possible, although Morse code transmission continued to be used until the 1990s.

All of the following parts involve talking radio, or cordless phones.

Homemade set up

The idea of ​​radio as entertainment began in 1920, with the opening of the first station established specifically for public broadcasting such as KDKA in Pittsburgh and WWJ in Detroit. More and more stations opened in cities across North America in the following years and radio ownership continued to increase in popularity. The radio set from before 1920 was a rarity, and possibly a military artifact. Sets made before about 1924 are usually made on wooden bread boards, in cabinet-style cabinets, or sometimes on an open sheet metal chassis. A home-made set remained a strong sector of radio production until the early 1930s. Until then there are more homemade sets used than commercial devices.

Initial device uses one of the following technologies:

• The crystal is set
• Set the crystal with carbon or mechanical amplifier
• Radio Frequency Tuning Basic (TRF) set)
• Reaction Set
• Super Regeneration Recipient
• Superheterodyne Receiver

Crystal set

This base radio does not use batteries, has no amplification and can only operate high-impedance headphones. They will only receive a very strong signal from local stations. They are popular among the less wealthy because of low development costs and zero running costs. The crystal set has the minimal ability to separate the station, and where more than one high power station is present, the inability to accept one without the other is a common problem.

Some users of crystal sets add a carbon amplifier or mechanical turntable amplifier to provide sufficient output to operate the speakers. Some even use a fire amplifier.

Radio frequency set set

Tuned Radio Frequency sets (TRF sets) are the most popular early radio classes, especially since RCA companies have a key on the circuit of superheterodyne circuits and it is more advantageous for companies to jump onto sets of TRF radio manufacturing. It used multiple valves (tubes) to provide RF amplification, detection, and audio amplification. The initial set of TRF only operates headphones, but in the mid-1920s it was more common to use additional amplification to power the loudspeaker, regardless of the cost. The sound quality generated from the "moving-iron" speakers used on such sets is sometimes described as torture, although by the late 1920s Kellogg-Rice dynamic (coils-moving) speakers had begun to seek help because of superior sound reproduction..

Speakers are widely used on TRF sets including:

• Move iron speakers (horns or cones)
• cans, magnets & amp; wire-based speakers
• moving coil speakers

The TRF set does not use regeneration, and only a few stages (usually three) RF amplifiers are tuned in series that provide a detector tube that extracts audio intelligence from RF signals. The TRF set, depending on the number of stages used, can have exceptional bad sensitivity (the ability of the device to capture weak signals) and the corresponding selectivity (the ability to separate adjacent stations from each other). The audio reproduction quality of the TRF set is limited by the available loudspeakers. "High Fidelity" did not become a radio marketing concept until the mid-1930s and did not materialize until the appearance of FM broadcasts.

The set of reactions, also known as regenerative recipients, depends on positive feedback to achieve an adequate gain. This approach provides high performance with a minimum number of expensive vacuum tubes, but these receivers tend to emit RF interference in their immediate vicinity. As a result, there is a large amount of hostility by neighbors of "regen" set up users over maladjusted radio transmitting voice squealing and blocking reception on nearby properties.

The initial set of TRF has two or three tuning buttons and a rheostats voltage control tube, all of which must be set up correctly to receive the station. Then (late 1920s) the TRF set has ganged tuning (one button is used to control all tuning capacitors of the stage simultaneously), the current home AC operation, and eliminates the filament voltage adjustment. All these changes greatly simplified the operation and made a household radio station even a child could operate, not the very skillful fans of the previous generation who were short. The reaction set also has a filament adjustment rheostats for each valve, and the settings again must be correct to achieve acceptance.

Superheterodyne receiver

In the early radio age, only RCA and a number of competing "prestige" radio manufacturers were able to build superheterodyne (superhet) receivers. RCA Corporation has exclusive rights to superheterodyne circuit patents and incur high licensing fees from other companies seeking to build superhet devices. RCA also vigorously demanded patent infringers. This situation tended to propel RCA to the forefront of radio manufacturers in the 1920s because of the higher efficiency of the superhet circuits-a situation that lasted until the patent ended in the early 1930s, at which time the superheterodyne low-cost recipient hit the market. Initial superhets (RCA-patent-era) are often used with relatively expensive moving coil speakers, which offer unavailable sound quality from moving iron speakers.

Most post-1932 commercial radio is superhets, and this technology is still used widely in today's radio receivers, implemented with transistors or integrated circuits.

The advantages of superhets are:

• Excellent sensitivity and selectivity
• Ease of designing sets for multi-band operation, enabling acceptance of foreign broadcast ("Shortwave")
• High stability
• Well controlled bandwidth
• A well-shaped RF passband avoids uncontrolled tone variations on the TRF set, and provides good selectivity

Losses before about 1932 are:

• The cost of patent licenses is high.
• The need for customized testing tools to perform conversion stage conversion alignment.

In general the technical and manufacturing advantages of the superhet ensure that the TRF set becomes quickly obsolete after patent restrictions on superhets are removed.

Agricultural radio

Prior to the Rural Electrification Act of 1936, most of America's agriculture had no electricity. Some did not receive commercial power until the 1960s. Until then, special radios are made to run on DC power. The earliest agricultural radio used "A", "B" and "C" batteries typical of the 1920s radio set; This "farm radio" is identical to that used in cities. Somewhat later, the farm set is made to run at 6 volts from a car battery or tractor, using an electromechanical vibrator to create a pulsed DC current that can be increased even though the transformer creates the required high voltage for the tube plate - just like a contemporary car radio. Other agricultural radios are designed to operate at 32 volts DC, from storage banks of lead-acid batteries filled from gas generators or wind chargers. The 32-volt system can also turn on other specially made equipment as well as electric lights around the farm. Other agricultural radios, especially from the late 1930s through the 1950s, again used a large "AB" dry cell that provided 90 volts for the tube plates and 1.5 volts for the tubular filaments, as did many tubular-based portable radios of the era.

Radio hole hole

World War 2 created an urgent urgent need for radio communications, and a set of protective holes was built by people without access to traditional radio parts. The protection hole radio is a simple crystal radio set receiver assembled together from any part that can be made by someone (very few) or criticized from discarded equipment. Such devices typically use domestic wires that are rescued for antennas, double-edged razor blades and pencils (or safety hoists) for detectors, and tin cans, magnets and multiple wires for earpiece. The razor blades of that era were chemically coated ("blued") and these layers could function as diodes, in the same way as galena-catwhisker detectors operate.

Wood console

Radio console is a household entertainment center in the age of radio. They were large and expensive, costing hundreds of dollars in the late 1930s. Tend to be a great acquisition for middle class families, this radio is usually placed in the living room. Most early console radios were high and narrow, but as the years progressed they got shorter and wider according to the Art Deco design rules that had become popular

Consumer radio is made by RCA, Philco, General Electric, Montgomery Ward (under the Airline brand name), Sears (under the Silvertone brand name), Westinghouse, Motorola, Zenith, and more. Brands like Zenith make some models ("Stratosphere") that go to very expensive radios, but mainly produce competitive prices that are affordable to anyone with a good income.

Some premium makers like EH Scott and Silver-Marshall are only affordable by very wealthy people because their prices are in the range of $ 500- $ 800 (and up) in the 1930s and 1940s, which at the high end is more than the cost of luxury cars.

Radio timber casing on table

Table top radio comes in various forms:

• "Cathedral Style", rectangular rectangle with rounded top
• The "gravestone style" is a tall, narrow rectangle like a gravestone
• The "Table top" is rectangular, with width being a larger dimension. Table top radios are usually placed in the kitchen, living room, or bedroom, and are sometimes used on terraces.

Bakelite

The availability of the first mass-produced bulk bakelite allowed designers more creativity in cabinet style, and significantly reduced costs. However, Bakelite is a brittle plastic, and dropping the radio can easily damage the casing. Bakelite is a black-and-white thermosetting plastic, and is still used in some products today.

In the 1930s some of the radio was produced using Catalin, which is a component of bakelite phenolic resin, without added organic fillers, but almost all of the historic radio bakelite is a standard black-brown bakelite color. Bakelite as used for radio cabinets is traditionally brown, and this color derived from ground walnut flour is added to the thermosetting phenolic resin as an extender and strengthening agent.

The plastic era

The affordability of more modern colored thermoplastics in the 1950s made the design a brighter practical. Some of these thermoplastics are slightly translucent.

Initial transistor radio

The invention of transistors makes it possible to produce small portable radios that do not require heating time, and use much smaller batteries. They are comfortable, although the high price and initial sound quality models are not as good as tube radios. Newer models match or exceed tube models in audio quality. The transistor also makes it possible to produce portable FM radio, which is not practical using a tube.

Transistor radios are available in various sizes from console to table-top to matchbox. Transistors are still used in radio today, although integrated circuits that contain large numbers of transistors have transcended the use of single transistors for the majority of radio circuits.

Radio transistors appeared on the market in 1954, but with high prices. In the 1960s, reduced prices and the desire for portability made them very popular.

There is something of a marketing war over the number of sets of transistors contained, with many models named after this number. Some sets even have non-functional rejection transistors that are soldered onto a circuit board, do nothing, so a sales pitch can advertise a higher number of transistors.

The vacuum tube radio and the original transistor radio were assembled by hand. Today's radio is designed with the help of computers and is produced with the use of a much larger machine.

Today's radios are usually uneconomical to repair because mass production and technological improvements in many areas make them very cheap to buy, while the cost of human labor and the cost of workers exploitation does not fall in real terms.

Car radio

The earliest car radios appeared shortly after commercial radio broadcasts began, but only experimental. They are expensive, require large air receipts, inconsistent receipts, and they require adjustment in usage, which is not very practical.

In the early 1930s most car radios, no longer experimental, were superheterodynes and used a vibrator power supply to increase low voltage to high voltage ("B" voltages anywhere from 90 to 250 volts) for vacuum tubes. Vibrators are relatively unreliable as electromechanical components of a limited life, audible hum, and produce radio interference. Some radios use larger and more expensive generator-generator generators or motor-alternators called "dynamotor" that play high voltage generators or alternators using DC motors 6 or 12V. Filaments are powered using 12V DC power and then 12V DC from the vehicle's electrical system directly.

With the introduction of transistors, which were previously only suitable for audio frequencies, the car radio was a valve set with the transistor output stage; makers are promoting them as transistor sets. Some historic car radios labeled as transistorized are the reality of this type. All transistor sets were eventually replaced with vacuum tubes after the transistor technology was upgraded and the price dropped significantly.

Chrysler and Philco announced an all-transistor car radio in the April 28, 1955 issue of the Wall Street Journal. Philco's car radio model is the first series of tubeless cars in history to be developed and produced. It was a $ 150 option for 1956 Chrysler and Imperial cars and hit the showroom floor on 21 October 1955.

Maps Antique radio

Heating time

Most sets of valves require a few seconds for the valve to heat up, although there are exceptions. The heating time changes when the valve passes through several generations of design.

• The universal light-emitting valve in the early 1920s came in a tiny fraction of a second, instantly effective.
• Anglers boring directly in the late 20s and 1930s came about a second. This type of valve has continued to be popular in battery sets for more decades.
• Indirect transmitters used in more or less all major valve radios from the late 1930s and beyond are slow to reach emission temperatures, with routine waiting times exceeding 10 seconds.
• The last generation of valves is nuvistors. These small appliances reach the emission temperature pretty quickly.

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Assessment

In terms of financial valuation:

• Catalin's plastic radio, new radio, and top-class console radio are on sale at the top of the market.
• The cathedral, tombstones and large table tops are the midrange
• The wood/bakelite counter tops are in a lower mass production bracket and are often sold for less than $ 40, although collection devices (Like DAC90, made by Bush Radio in the UK) often sell more.
• Assessment of the 1920s and 1930s is highly dependent on condition and appearance. A well-presented breadboard board orders a high price tag, but a sample that is too thick or boring does not. Although such sets are now quite rare, problems in using pre-1930 battery-powered sets tend to depress their selling points.

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Use of ancient radio

Commercial Set Operated Path

Using classical radio generally requires inspection and repair or repair before it can be operated safely. In most cases, at least the radio-operated power supply portion must be updated to prevent damage to other components, but it can be assumed that most vintage capacitors are electrically "leaky" and that the electrolytic capacitor in the power supply loses capacity (causing excess "hum ") or shorted (potentially causing short or destructive short circuits). In their home country, they only meet the limited security standards of the day, and almost no one uses a fuse.

An AC-operated radio using a power transformer requires repair and repair of the power supply before operation, as any failure tends to compress or damage the power transformer, requiring expensive repairs.

The AC/DC set using a power transformer should not be a "cork burner" using a resistance cable to drop a channel voltage, or warm/hot chassis radios using a series of series strings in which the voltage increases to line voltage. They are named "AC/DC" because they operate on AC or DC voltage, which is not possible with a transformer based set.

"Curtain Burner" sets are common in early 30s "midget" sets. This name is an indication of the problem - the line cable contains a resistor to drop the voltage and dispose of substantial power in the cable itself. When operating properly and line wires stretch to full length, the cord becomes "warm" and safe enough (until the heat creates a cracked rubber insulation). When the cable is rolled or insulated (like from a curtain that depends on it) it can get very hot, and cause a fire. Resistance line cords are no longer available and vintage cables are no longer servicable, so radio has to be redesigned in part by either dropping capacitors, dropping resistors, or some other solution for safe operation.

The AC/DC set does not have a resistance line cord, instead of a series of tubular filaments that are added to the channel voltage, effectively transferring resistance into the radio. They use conventional line wires. This is the most common vintage radio in the US after about 1940 or so, because they are so cheap to produce. They are less common in areas with 240 electric power, because there are some common tubes built to operate at the required high voltages. BC (medium wave/"AM") only radio like the "All American 5" design, and then AM/FM radio with more tubes, and even television built using the same idea, because simplicity and cost are as low as possible./dd>

One type of radio AC/DC can present a "hot" line of line voltage on the radio chassis ("hot chassis") or isolated from the chassis by one capacitor ("warm chassis"). It presents a security problem, since it depends on the direction of the non-polarized plug, the heat side of the utility voltage can be connected directly to all metal parts of the radio whenever it is plugged in, regardless of whether it is supported or not. Proper repair or restoration requires an isolation transformer to remove the direct connection, and care must be taken to never touch the metal part of the radio (chassis holder screws, empty control shaft, etc.) When the radio is plugged in. Many radios with hot chassis use an interlock on the back to ensure that the line is disconnected before the rear is accessible for tube replacement.

Then the transistor-based AC radio table usually uses a power transformer and operates safely, but with the possibility of humming of a failed electrolytic capacitor in the power supply, and possibly low volume of other failed electrolytic coupling capacitors. There are some early transistor radio tables using the principle of "hot chassis", but this is very rare.

Battery Operated Started Set

The minority of all-in-one sets of commercial ac commercials that emerged in the 1930s were plug & amp; play. Such devices should be checked for the possibility of live metal being accessible to users, and general safety checks are recommended. A lot needs to be fixed.

But not all types of pre-Depression era radios are more demanding to use, away from plug & amp; play. Setting up such radios requires a bit of electronic skill.

There are some problems with them:

• The failed component is expected, and this should be found error then repaired
• Component component improvements, but not trivial
• Some of these sets never work properly and may benefit from some trained debugging
• 3 power supplies are required to replace the used A, B and C batteries (unless the bias itself is used) (or DC power).
• A small detective job is required to know what PSU voltage is required
• Long wire antenna must be installed
• Installation of local soil (earth) is often required, and quite easy
• High impedance (or transformer) speakers are required
• Some ways to keep fingers away from direct connections that are exposed to the back are wise, and are often legally required.
• With 1920 and earlier sets using bright emitter valves, end users should understand the use of filament rheostats to avoid rapid valve failure.
• Users should be aware that allowing a set of historical reactions to oscillate causes them to transmit interruptions, which are illegal.
• Negative supply The DC host set must have its base capacitor skipped to convert it from the live chassis to the grounded chassis.

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Sound quality

The sound quality of the antique radio depends on the technology used in the set. This type of speaker is the main differentiator, with batteries or batteries also making a significant difference.

All valve sets produce second harmonic distortion, which is quite euphonic. Some also produce significant 3rd harmonic distortion, which is less pleasing to the ear.

Discussions are often heard about triode versus pentode valve distortion, and single ended versus push thrust, which affects the type of distortion generated, but this problem seems to be a secondary practice to the one discussed in this article, and it is well covered. in another article.

Loudspeaker Type

Moving iron speakers

The home-made pre-war sets usually use some form of moving iron speakers, usually horns or cone loaded, and sometimes the disc loaded. The sound quality of the radio is generally not important, because almost any defect in the audio signal will be disguised by the butcher visited by the loudspeaker. The question of sound quality is strongly dominated by speakers in these cases. Moving iron speakers suffer the following defects:

• Gross non-linearity
• Distortion of intermodulation weight
• Small bass response
• Bad treble response
• Strong resonance that is not muffled in the middle of the audio spectrum
• Noisy noises when presented with a loud bass tone
• The tendency of the moving iron to stick to the polar pieces, resulting in a 'whack' sound followed by very little sound output.
• Impedance impedance dirty
• Need for customization
• Prone to demagnetization
• Speaker horn is very directional
• Floppy cones are easily damaged

The sound of the moving iron speakers has a strong and clear character.

They are far from being faithful in their audio reproduction, and their technical specifications are not well controlled. An example is their electrical impedance, which varies across the audio spectrum with a ratio of more than 100: 1.

It is not unusual for an electronic student, when hearing some specifications of this device, to conclude that they are unlikely to be able to reproduce speech. But they do it, and in a voice that can not be misinterpreted for anything else.

Speaker dynamic inductor

It enjoys a brief success but is quickly eclipsed by the moving coil speaker. The Dynamic Speaker Inductor solves the worst problem of a kind of moving iron before, and provides a relatively pleasant listening experience. The major flaw of the ID loudspeakers is a poor treble response, giving them a dull drone boring.

Move speaker coil

These speakers are mostly of sufficient quality that radio characteristics become significant. The combined set of transformers has lost bass & amp; reduce the treble, the network leakage set where rf and af reinforced by the same valve gives some nonlinearity, and the output stage always gives a bit more non-linearity. But the quality of the moving set of coils can be fun, and wrong for modern portable radios.

Audio Idiosyncrasies

Battery set

Partial loss of bass and high frequency of normal treble, such as a small portable radio today. A small number of non-linearities are also present.

Some sets are susceptible to crossover distortion when the battery voltage drops. This is a kind of unpleasant rough distortion. In this vulnerable sequence, vital attention is taken to avoid it, or in some cases minimize it.

Parent set

Most old valve radios are in this category. The main set has the same defects as the battery set, but has a redeeming feature that gives them warm & amp; sounds fun. Audio output from almost all sets of main valves is modulated by 50 & amp; 100 Hz or 60 & amp; 120 Hz, creating extra frequency arrangement in audio signal. This additional content gives the impression of warm & amp; depth, and easily mistaken for a good bass response.

This modulation is made by several factors that work together:

• The low value smoothing capacitor causes significant Hz ripple of 100/120 Hz on the HT line.
• Significant 50/60 Hz internal cables, ac heaters and high impedance circuits cause 50/60 Hz injection to all radio stages
• Non-linearity valves at all stages

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See also

• Vintage amateur radio
• Radio history

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References

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External links

• The Antique Radio Shack- A high end source and an unusual antique radio from the 1920s to the 1950s.
• Classic Radio Gallery - Web site that contains a large antique radio view gallery.
• Phil's old radio - Radio collections ranging from models that stood on the floor of the 1930s to pocket transistor radios in the 60s.
• Antique Radio: A Collector's Resource - A website containing forums, galleries, and more.
• Philco Repair Stool - The website contains instructions and information about Philco radio and more.
• The New Jersey Antique Radio Club provides an environment where new and experienced collectors can share information about radio history and recovery.
• Attic Radio - Over 1,200 antique radios for sale, with photos.
• Archive Attic Radio - Photos of over 11,000 unique identifiable radios, plus links to audio, amateur and test equipment.
• WhiteRadios.com - Radio Antiques, History, and Assessment Gallery - A website dedicated to radio collecting and perpetuating love for hobbies.
• Curious Antique Radio (based on DMOZ).
• Antique Radio Classes the World's Largest Publishing for Collector and Recovery of Antique and Antique Radio, TV, Audio, and Other Electronic Equipment.

Source of the article : Wikipedia