Click on the picture for the situation before restauration
Radioset, blocksystem, consisting of four connectable elements
In brown oak cabinets with ebonite front, Bakelite knobs and brass coupling strips.
The set consists of a tuning unit with a fixed and a movable coil, a HF unit with 1 tube and 1 coil, a detector unit with 1 tube and a power amplifier with 2 tubes, probably all bright emitters. The remains of 2 Philips DII tubes were found inside the unit, so the probable valve line-up was Philips DII (HF unit), Philips DI (detector) and 2 x Philips DII (amplifier). The radio came with a set of original coils. All coils have a solid and a hollow pin. The coils look British, with a pin diameter of 4.8 mm and a center distance of 19 mm. One of the coupling transformers is from the German Böco (almost certain not original), and the other is stamped DPM. There are no other marked parts.
The texts "Erres G RADIOFON" and "R.S. Stokvis & Zonen" are placed on the HF unit. The other cabinets have the text "RADIOFON", with the exception of the last, the power amplifier. An Erres G, made by Dutch firm N.S.F., was introduced in the Netherlands in 1923, but it does not look much like this unit. The only similarity is that it is also an HF module. The link with Dutch trade firm R.S. Stokvis & Zonen (using the brand name Erres) is still not clear.
The set was found in Finland but was most likely made in Norway.
History
The radio set comes from Finland, where it was left in a summer house in 1939 by a Fin who fled to Sweden at the outbreak of the Winter War between the Soviet Union and Finland, which began on November 30, 1939 and ended on March 23, 1940. After WWII, in 1949, the summer house was bought by a Finnish lady who found the radio there. A grandson eventually sought information about Erres and Stokvis and ended up on my website. In 2018 the set was given to me. It was shipped to the Netherlands in January 2019. With many thanks to the generous giver: Carl Fredrik Sandelin, Helsinki, Finland.
Given this history, the radio could have been made in a number of countries in the wider area. Finland itself is not an option because the abbreviations for long and short wave do not match the abbreviations (L and K) used on the tuning unit. In Finnish, the letters P (Pitka) and L (Lyhyt) would have been used. Norway is most obvious the country of origin.
In Norwegian sources, Radiofon is mentioned as brand of Einar Rustad & Co, Rosenkrantzgt. 20/28, Kristiania (Oslo). This manufacturer is active in the mid-20s of the last century. From 1923 the company makes radios, sells radio lamps under the brand name "Radiofon" and material for DIY sets. The company's advertisements appear from 1923 to 1925. In 1926 the company went into liquidation and in 1927 the written settlement took place. After the Second World War, a company called "Radiofon" (Radiofon-Radiofabrikk, A/S) reappears in the city of Bergen, but this company seems to have nothing to do with the Oslo-based company from the 1920s.
The building in Rosenkrantzgate 20 in May 2019. The six-storey building dates from 1916 and was designed by archictect Christian Reuter. The confectionery factory of Fred T. Møller was located here, and later also Radiofon of Einar Rustad. It now houses Kelly Services Management.

The March issue of 2008 of "Hello! Hello!", nr 101, of the Norwegian Radio Association (Norsk Radiohistorisk Forening, NRHF) shows a picture of a slightly newer Radiofon radio, probably from around 1924 (left), where especially a fairly unique reversing switch stands out - and to a lesser extent - a knurled nut with which the modules can be connected to each other using a brass strip.

A Radiofon receiver ca. 1924
Advertisement in Fiskaren September 19, 1923
In Norway, the first experimental radio broadcasts begin in the Spring of 1923 using a 500 Watt transmitter in Tryvannshøgda near Oslo. Everywhere in the country, daily newspapers offer radio courses to subscribers. The courses are given in collaboration with the company Radiofon, which also supplies the equipment. The cost of the course is deducted from the purchase price. In newspaper "Nationen" e.g., on 14 September of that year a radio course for its subscribers is announced: "Radiokurset begynder om 8 dage". Radiofon units are used in this course, according to this excerpt from the article: "For the participants of the course there is, as you know, the possibility to acquire very cheap but completely effective radios. The devices are from the well-known "Radiofon"-type. This means that all units are housed in cabinets of the same size and with the same appearance, so you can choose how large you want to make the radio when you purchase the individual "blocks." Many would like to start with a simple device, easy to operate and inexpensive. If you want, after further exercise (and saving enough money ...) new units or amplifiers can be purchased.
These can always be easily connected with the units you have already bought, so gradually, the range and volume can be adjusted. This major advantage of the "block system" means that all "Radiofon" devices are now manufactured according to this system".
It seems that this radio combination is one of the first to come on the market in Norway.
Data Valves  
Serial number: none
Dimensions (h×w×d): 56 x 20,5 x 10,8 cm
Made in: ±1923
Given to me in: 2018
Voltages: 4/80 volt
   

Click on a valve for more information

Circuit

What was broadcast in 1923?

 

Listen to "High Society" by King Oliver's Jazz Band, recorded in Chicago, June 24, 1923

The Radiofon tuner
With a fixed and a movable coil, an antenna connection, a series / parallel switch (L/K), a tuning capacitor and a connection for a frame antenna below.

The Erres G / Radiofon HF amplifier
With one tube, a fixed coil, a switch for switching off the module, a switch for polarizing the coils on the tuning unit. (in this way, coils having a different winding direction can also be used), a tuning capacitor and a rheostat for the filament current.

The Radiofon detector
With one tube, two clamps, where a grid leak resistance can be fitted (for slightly later tubes, not always necessary with bright emitters) and a rheostat for the filament current.

The amplifier
With two tubes and two rheostats for the flament current. Below, a binding post for a set of headphones.

This page was last edited on 10.10.2019