This is a Polle Royal table radio, manufactured by the Royal Radio Corp. of Providence, Rhode Island. I estimate the date of manufacture to be between 1923 and 1925. I have been unable to locate much information about the company other than it was one of the many small manufacturing companies to come and go during the infancy of the radio industry. Many of these small independent radio manufacturers were quite successful for a few years only to fail during the great depression. Many turned out a high quality product. This particular set appears to have been targeted at the higher end of the market and was technologically advanced for its day. It consists of a 5 tube Bakelite chassis using type #01 tubes and a Bakelite front panel featuring silk screened markings with gold leaf paint. The knobs feature machine etched pointers also filled with gold leaf paint. The cabinet appears to be pine or poplar with an ebony stain. Like all radios from this time period, it is a battery powered set, but this gave it the advantage of operation in both the city and rural areas not yet electrified. Unlike the kit radio that I featured two articles back that was designed to maximize battery life, this set was designed for maximum performance at all times and was probably sold to consumers who were not as concerned with the price of batteries. Although I have not been able to determine the original selling price of the radio, similar high end sets typically sold for a little over $200.00, the equivalent of $2600.00 in today’s dollars .
In my humble opinion, the vacuum tube rates among the most important technological inventions of the past century. It is considered by most to mark the birth of the electronic age, and until the invention of the transistor in 1947, it stood alone as the heart and soul of just about every electronic device developed.
Opinion varies over just who should receive credit for inventing the device. The debate focuses on four well known inventors; Americans Thomas Edison and Lee DeForest, Englishman John Fleming, and the German physicist Wilhelm Conrad Roentgen. For the purpose of discussion, let us define a vacuum tube as a vessel most often made of glass, porcelain or metal, from which as much air as possible has been pumped out, containing a number of electrical elements and performing a useful function. Based on that definition, all of them qualify in one way or another.
In 1895 German physicist Wilhelm Conrad Roentgen discovered that by placing two electrodes in an evacuated glass tube and applying high voltage to these electrodes, that not only would electricity flow through the vacuum, but that x-rays would be generated by the impact of the electrons striking the steel plate. Mr. Roentgen was not the first to observe that electrons could be made to flow in a vacuum, but his invention of the x-ray tube was probably the first useful and practical application of the phenomenon. As a result of his discovery, he was awarded the first Nobel Prize in Physics. Both of the elements in Roentgen’s original tube were unheated. It is not easy to get electrons to flow in a pure vacuum between unheated elements. Fortunately for Mr. Roentgen, vacuum pumps were not of the highest quality in 1895, and traces of remaining gasses became ionized (electrically charged) allowing current to flow.
Thomas Edison invented the light bulb in 1879. He did so by placing a carbon filament in a glass enclosure and pumping all of the air out of it. His early bulb had one major problem. Carbon seemed to evaporate from the filament and deposit itself on the glass, darkening the glass and thus reducing the useful light output. He noticed that more carbon seemed to evaporate from the end of the filament attached to the negative terminal of his power source. A year later he placed a second element in the bulb, a small metal plate near the filament. He observed that electricity would flow through the vacuum from the hot filament to the plate. He was unable to explain this effect but was hoping that the carbon would also be drawn to the plate instead of darkening the inside of the bulb. When this did not happen, Mr. Edison discontinued research on the phenomenon, but not before obtaining a patent for the “Edison Effect”, hoping that it might have some commercial application in the future.
John Fleming was an engineer, physicist, and professor who taught and lectured at a number of British universities. He presented an important paper on the theory and design of electrical transformers in 1892. He crossed the pond to take a job in Thomas Edison’s lab and became curious about the “Edison Effect”. Later, while working for Marconi Wireless he began conducting further research and discovered something that Mr. Edison had overlooked. He noted the fact that electrons would only flow in one direction, from the hot filament to the cold plate, and only when the filament was made negative, and the plate positive. In 1904 he patented this device as the “Fleming Valve” for use as a detector of radio waves. The English still refer to vacuum tubes as “valves” to this day. Ironically, his first vacuum tube was replaced by the first “solid state” device, the gallium crystal (henceforth the term “crystal radio”) about a year later. Larger versions of his “valve” would later become rectifier tubes used to convert AC to DC.
Lee De Forest obtained a Ph.D from the Sheffield School of Science at Yale University. His dissertation was on the subject of radio waves. Despite his degree, he remained more of an intuitive inventor like Thomas Edison, than an academic theorist. Upon inventing the vacuum tube as we now know it, he was quoted as saying he “didn't know why it worked, it just did.”
The average person probably wouldn't know what this object was if they came upon it at an estate sale or in an antique shop. They would have less of a clue were it not displayed with the headphones, which are also from the same time period. The two largest knobs are graduated with a scale that reads 0 to 100, the others are not labeled at all. If you were to turn it around, you would see the first clue that it might be a receiver of some type. There are seven thumb screw terminals, two of which are labeled antenna and ground. Three are labeled "B Battery", and the remaining two are labeled “A battery” and "Common". There is nothing to indicate what frequency it receives, such as 540 –1600, or whether it is AM or FM.
To a collector of vintage electronics, this item would definitely warrant a closer inspection. Since this is the first of my articles on vintage radio, I decided to go way back to the beginnings of radio as we know it today, the early beginnings of the vacuum tube era. This radio is a very early set, built with parts which appeared on the scene between 1919 and 1922. It may have been a kit radio, or it may have been designed and built by a hobbyist from plans found in an early wireless magazine. Perhaps it was built to monitor the broadcasts of the first licensed broadcast station KDKA which hailed from Pittsburg PA in 1920. It may have been built to allow its creator to monitor wireless telegraph transmissions between ships and shore stations, or for use by an early amateur radio operator.
There were receivers which predated the age of tubes. An Englishman named John Preece began wireless transmission of Morse code for commercial purposes as early as 1892, and Marconi made his famous transatlantic transmission on December 12, 1901, but I’ll cover those technologies at a later date.
This is one of the common questions that I am asked whenever the subject of vintage electronics crops up, which is often since I am an avid collector of antique electronic equipment.
Webster's Collegiate Dictionary defines "antique" as 1: a relic or object of ancient times or of an earlier period than the present. 2: a work of art, piece of furniture, or decorative object made at an earlier period and according to many customs laws at least 100 years old. 3:Made in or representative of the work of an earlier period.