Pre 1914 Radio Communication

	1: Marconi Wireless Cabin on Board the "Tongue" Lightship. The Trinity Brethren were among the first to recognise the value of Marconi's invention to those who go down to the sea in ships. Ten years ago they ordered the equipment of the East Goodwin Light-vessel with wireless apparatus. Communication with South Foreland Lighthouse, 12 miles distant, was most satisfactorily maintained. The '' Tongue " installation is typical of the many lightships now fitted.
	2: Schooner "Volunteer." Chartered by the Newfoundland Government in 1902, for the purpose of erecting Marconi stations along the coast of the Labrador. The ship was used as a stores and dwelling place by the engineers fitting up the installations, who had to carry out their work in weather, and under conditions, of Arctic severity.
3: Mr. Marconi and Assistants at Cape Breton Station. The illustration shows Signor G. Marconi with five of his assistants outside the High-power Wireless Telegraph Station at Cape Breton, Nova Scotia, and gives some idea of the severity of the weather conditions under which Sig. Marconi and his staff carry on their work at times. Mr. Marconi is the third figure from the left.
	4: G. Marconi. Born at Bologna, 1874 Married 1905, daughter of Lord Inchiquin. Carried out first experiments in wireless telegraphy at Bologna. Same first tested in England between Penarth and Weston. In 1899 established wireless communication between France and England, and Trans-Atlantic service between England and America in 1907. In addition to the warships of the British and Italian Navies, most of the ocean liners have the Marconi apparatus.
5: Marconi Station at Banana, Congo Free State. This station was erected by the Marconi Company in July, 1901, to the order of the Congo Government for communication with a similar station at Ambri-zette, Angola, and was operated by natives, illustrative of the ease with which the Marconi apparatus can be mastered and worked. Station now dismantled.
	6: Marconi Station at Niton, Isle of Wight. Erected by the Marconi Company in 1901. Situated on the most southern point of the island. Many early experiments were carried out there. The station has a working range of 150 to 200 miles, and carries on a public telegraph service with ships voyaging between the United States and London, Germany, France, and Holland.
7: Messina  Station. The station at Messina, destroyed in the recent lamentable catastrophe, was illustrative of the multifarious usages to which Marconi's invention may be put. Connecting, as it did, the Italian Peninsula, by means of the similar station at Eeggio di Calabria, with Italy's largest neighbouring island, the service of the Italian State and Sicilian Railways was considerably accelerated. The station is being refitted.
	8: Cape Cod Station. Erected in 1900, this station transmitted direct to a similar station at Poldhu, in Cornwall, England, 2,800 miles distant, an inaugural message from President Roosevelt to His Majesty King Edward, in January. 1903. The poles carrying the aerial wires are now replaced by the familiar lattice work towers. It has provided since 1904 a daily news service to the principal Trans - Atlantic liners.
9: Wireless Telegraph Motor Car. The illustration shows the first application of the Marconi system to moving stations. This steam motor car with its light zinc cylinder serving as an an antenna, was able to communicate, as long ago as 1900, with a corresponding station up to a distance of over 20 miles. Moving stations carried by mules or light field carts now provide instant means of communication up to more than 100 miles.
	10: Cape Breton Station. Erected by the Marconi Company in 1902 for Trans-Atlantic communication, but has since been rebuilt. Now carries on constant communication, day and night,- with station at Clifden, Ireland, transmitting public messages, and supplying a daily news service to Atlantic liners for publication on board. The view is taken from seawards in mid-winter.
11: South Goodwin Lightship. Situated at the southeast corner of the Goodwin Sands. Was equipped with wireless telegraphy in May, 1905, by order of Trinity House. Communicates with stations at Dover and North Foreland. Has been of great service in summoning assistance to vessels in distress on the Sands. Six lightships in all have now been equipped with wireless telegraphy.
	12: John 'Jack' R. Binns. Born at Brigg, Lincolnshire, on 16th Sept., 1884. Entered Marconi service as ship telegraphist at the age of 20. By his devotion to duty he was the means of saving 2,000 lives on the S.S. "Republic," when in collision in the Atlantic, remaining at his post for nearly 50 hours. For this he received an address from the Mayor of Peterborough, and a special presentation from the Directors of the Marconi Company.

13: Jack Binns' Cabin on the "Republic."  The illustration depicts the wireless cabin on the S.S. "Republic" from which Jack Binns sent out his now famous call " C.Q.D.," which brought help from all quarters to the "Republic " after her collision with the S.S. "Florida." On the left are the transmitting instruments and key, and on the right the receiving instruments and recorder. The cabin was partially destroyed in the accident.

14: First Type Transmitting Apparatus. The illustration shows one of the early induction coils and oscillators used by Mr. Marconi for the production of Hertzian waves as employed in wireless telegraphy. The discharge which sets up the ether waves takes place between the two large brass balls, which are partially immersed in oil. , This type has been considerably improved upon.

15: Marconi  Syntonic Receiver.  Invented by Mr. G. Marconi. By its means several wireless messages can be received at the same moment. Two or three, each "tuned" to a different wave, will, if connected to the same "aerial" wire, pick out and record the particular message transmitted by the station using the same '' tune." It is thus possible to receive English, French, and German messages at the same time, each on its own instrument.

17: Marconi Station at Holyhead.  Opened for communication with ships entering and leaving Liverpool, in 1901. From left to right is: Coherer receiver in screening box (front opened), transmitting "jigger," Morse inker with battery of Leyden jars behind, transmitting key, and induction coil by means of which the oscillations, or waves, are created. Stations of this type have a working range of from 150 to 200 miles.

18: Marconi Cabin.  A typical Marconi installation on board ship. The instruments shown are, reading from left: Receivers, Morse recorder, Leyden jar battery, transmitting key, and transmitting coils. These sets enable regular commercial communication to be conducted at distances up to 200 miles, the messages being received on a tape. In the latest type, the messages are received by sound through telephones at much greater distances.

19: Marconi Magnetic Detector.  Invented by Mr. Marconi in 1902. Based upon the change taking place in an iron band travelling between two magnets, when affected by Hertzian waves, which causes a sound in the receivers similar to a telegraph buzzer. Records signals at 3,000 miles. The simplest and yet the most perfect wireless receiver yet invented. Rapidly replacing old coherer receiver where paper tape records are not required.

20: Marconi  Portable Wavemeter.  Invented in 1908 by a member of the Marconi staff, for the measurement of electrical oscillations ox-waves employed in wireless telegraphy. By varying the adjustment until the loudest signals are heard in the telephones, the wavelength is indicated automatically on a scale. Weighs 6 lbs., and only measures 9 ins. by 4 ins. by 6 ins. One of the most useful contributions to the art of wireless telegraphy.

22: Marconi Wireless Cabin on Atlantic Transport Liner.  One of the earlier type installations. The vital portions of the apparatus are duplicated (see two induction coils or transmitters at extreme ends of picture, and the two coherer receivers in screening boxes on the left). In centre is Morse recorder, Leyden jars, and, in front of coil, the transmitting key.

23: Receiving Room (High-power Station, Clifden).  The illustration shows an operator at the High-power Marconi Station at Clifden, Ireland, receiving a message from Glace Bay. Nova Scotia, over 2,000 miles away. Receiving is done by sound through a pair of telephones similar to those used by telephone switchboard operators, and ia carried on at a speed of about 30 words a minute.

24: First Type Lecture Apparatus.  One of the early sets of apparatus used for lecture purposes. To the right is the coherer, tapper, and relay, and on the left a call bell with telegraph sounder. The component parts are the same as in the commercial receiver, but more compactly arranged with the view to easy portability.

	Marconi Receiving Apparatus on an Atlantic Liner. Reading from left to right, the instruments are : Special side lever transmitting key, screening box containing coherer receiver, on which stands a tape wheel; behind is a switchboard carrying starting and regulating switches, voltmeters, ammeters, pilot lamps. The tube from top of screening box is the switch throwing receiver in and out of action by means of the side lever of the key.
	21: Marconi Wireless Telegraph Station, Bari, Italy.  Erected by the Marconi Company for the Italian Government. Now forms part of the Government network of stations for public service with similar station at Antivari (Montenegro) and other places. The two towers support the aerial, consisting of a number of wires arranged in the shape of a fan, point downwards, which lead into the instrument room.
	25: Italian  Portable Marconi Station. This automobile Marconi station is intended for military purposes. It has a working range of 100 miles, and can be brought into action in ten minutes. In addition to propulsion, the engine is used for raising and lowering the aerial elevator on. the roof, and for generating current for the apparatus. Messages can be transmitted and received while travelling at half speed.

Crown TR-690

Crown TR-690 Personal Portable Radio  (sent in by Paul Rumpf in Australia)

The radio was bought by my dad James in around 1965. He used to take it to the footy (Aussie rules) to listen to the  commentary. It was playing up and dad asked me to fix it. This was around 1990. Dad left us in 1996, and I never actually got around to fixing it until now with the Covid 19 lock-downs (lockups). Repairing these things is daunting at first sight because the compactness and the PCB tracks are all unfamiliar. The circuit diagram has been traced as well as could be done without taking components off the PCB. As a basis for the circuit I based the drawing on a ‘typical’ Japanese 6 transistor radio.

similar circuit diagram

Notes:-

• The mixer transistor is 2SA102, and IF transistors are 2SA101. Typical emitter current is around 0.5 mA for Q1 and 3. Q2 is the AGC transistor and the emitter current varies with signal level. 
• The self-oscillating mixer Q1, has the local oscillator signal fed through the emitter of Q1. Accordingly the emitter resistor is NOT bypassed with a capacitor. 
• The variable tuning capacitor in these types of radio have usually used different capacitance values for the aerial and the oscillator sections to eliminate the need for a padder. In this design, the two capacitor sections appear to be identical because there is a small capacitor (padder) in series with the oscillator section. 
• The bias feed resistors for each RF transistor have been assessed by measuring the ‘Base bias current’ by connecting the mA meter from the transistor base to ground. Q1 and Q3 current: - 0.2 mA; Q2 current 0.085 mA. 
• Emitter currents are around 0.5 mA. 
• The bias point for Q4 has the emitter voltage at about half the supply voltage; ie -4.5 Volt. The two problems with this radio were (1); the earphone jack had a short which shorted the voice coil and (2); there was an intermittent open circuit between the collector of Q4 and the coupling transformer primary winding. 
• The attached images should help to understand the layout. Audio quality is just OK; there is no crossover distortion. 

 Hope these notes help someone.

Editors notes:- I've found with this design of circuit, the 3 electrolytic's tend to fail, especially the 10uf (or similar) between the volume control slider and the base of the first audio amp. Causing low volume, the others cause instability or squealing.

Nice publication of Crown transistors

Radio symbols named

These are early US symbols, other countries may have designed their own. The first 3 valves are battery designed with direct heat to the Cathode and use less current than mains valves, they were improved over the years. The Screen Grid valve was later called Tetrode. These symbols were draw-up in the early days of radio or telegraphy and many are still in use today. Condensers were later called Capacitors.

Some later improvements the the vacuum valve/tube shown here in UK style

1929, 3 valve home build (restoration)

 

I was lucky to find this beauty at a reasonable cost along with BTH horn speaker from a guy in Wednesbury in West Midlands. They were in an unrestored grubby state, but with no real damage to the cabinet that would have been professionally made as an upgrade after a home build had been built. The problem with home builds is that a circuit can never be found and I had to reverse engineer one for myself. I was quite surprised how sophisticated it was. With 3 separate HT supplies, 1 grid bias battery and a 2 volt heater accumulator required to fire the giant up. I later found the reproduction period hall table to put it on - that I found on Facebook sales in Erdington.

The repair

All valves were pretty much exhausted and needed replacing. The screened grid PM12, the top cap broke away and I had to etch the glass back (with a grinding tool) to re-solder a wire to it. I made a 2v power unit with a 'buck converter' i/c and fitted that a 2 x 1.5v batteries inside a plastic box (originally the store box for a JVC car stereo front) nice clip lid to give access to replace batteries. The i/c's are found on line for a 'buck', lol

2v power pack I made with 'Buck' i/c, a switch and an LED to remind me it was on.

The grid leak battery was still in it's holder on the rear, so I made a carboard copy and installed a 7.7v battery inside (lot's of 1.5's in series.) Didn't re-use old one it had been tar filled.

Grid leak batteries new and old

The 3 HT units I made with 10 x PP3s in series fitted in the Kodak boxes they were posted in, Only gives 90v per rail, but most calves will work down to as little as 30 HT. To save space I fitted the 3 x HT battery boxes in the screened can middle unit at rear.

This photo shows the inside after a good clean-out of spiders and webs, as you can see the radio is constructed in 3 compartments; left: screen grid, RF amp and detector unit, centre: feedback and tuning, right: audio amp and tuning.  A is where I etched the wire back to glass top of valve, B is hidden behind screen can but needed a 1uF the was open circuit, HT decoupling, and C was the Inter Stage audio transformer(TX1), 3:1 ratio, that was open circuit, luckily I had some period parts to replace them. The plug in coil in the centre area I moved forward a little to give room for battery box's.

Even the inside of the cabinet had been varnished, so made cleaning years of dust away a doddle. The hole of the inside slid out of the cabinet with only the bias battery fixed to the rear. Because the cabinet was so dark, died a mahogany colour I added a collection of cigarette cards from the mid 20s showing and naming all 1920s radio components for the constructer, this brightens the whole look of the unit considerably.

Even the aluminium screening can, un-seen when radio running was given brush engraved finish and a removable lid for the top was also added. The BBC had insisted these units were better screened by the late 20's due to interference being caused with neighbour's radios, due to local oscillators. 3 plug-in coils were fitted and would need to be changed for LW reception if needed. Many terminals at rear for all the batteries to be wired plus speaker with more for aerial and earths. I touched them up with Tipex to highlight symbols on them.

Revophone 349 crystal set (1923)

 

It's a bit complicated this one, lol I found the empty Revophone box in one buy and the chassis was found in another buy. The twin tapped coils had become highly tangled and I spent quite some time putting that right. The brass name plaque came from underneath the radio, so I moved it to the top, the chassis was an unknown manufacturer but may be a Revophone of another model, still confused.

The tangled mess before I tackled it

Keeping the old look I cleaned-up the crystal housing tube, re-made the cat's whisker and painstakingly checked the continuity between all the wire switch terminals, of which there was many. The nice thing about lidded 20s radios is that the Ebonite is protected from the Sun's rays that turn it a brown colour with age. 

The circuit here, as with most Crystal Sets is very simple and needs no power source, all the energy is in the airwaves of local transmitters, usually b/w 50-75 miles away using high power is all it needs. In fact the power is that high, I read once the a cottage near a transmitter site was draining the current for the transmissions using large loop of wire in his loft, it was enough to power his lighting. He was found out and fined, lol Anyway back to the radio ... 4 terminals are for aerial, earth and headphones, a long length of will is needed for an aerial as indicated by the original label in the lid. The layout is upside down on that diagram, 'cus it was another model.

The factory was very large and employed many people from the local Tipton, West Midlands area during it's hey days of the 1920s and 30's. They made cookers, fires and even street lighting under the name Revo, when the radios were being built they offered a crystal set the size of a tobacco tin at a bargain price of 5 shillings and 6 pence. The site was located along side the Birmingham Canal for ease of shipping in those early horse drawn days of the industrial revolution. More can be found here:- Tipton History site

Bread bin home build 20's Parts

 

A 1920s style radio and parts in a 2019 bread bin with folding see through lid. My design was based around the General multi-coil 3 function unit; that's aerial loading, grid coupling, and reaction coils with 3 control knobs all built into one unit.

L1, L2 and L3 all housed in a General made unit

The unit is shown here with face plate and control knobs removed. I was lucky to find this on line cheap as part of the Bakelite facia was broken, but I didn't need it in this job it was really built for a wooden front. In my design you need to open front to tune controls, and closing them after keeps dust away and also allows you to see internal parts, about 20 in all if you add connecting screws. The circuit above shows the 2 valve design. Coil 1 receives the signal and had a tapped connector that then feeds it across the 300pf tuning capacitor.

where it is tuned to the required frequency and fed by coupling capacitor to the G1 of the Triode valve that has a Grid Leak resistor (2.2M) negative bias to chassis causing the valve to rectify the incoming RF signal and amplify with the help of feedback from coil L3 that is a Trickle Coil, that means it's loosely rotated inside the aerial coil to a point where feedback is controlled without whistling. 

Hard to capture picture of Trickle Coil inside main housing of General made coils

I've added a photo of the 2 valve holders that I restored, before and after. They were silver plated copper, so it cleaned up nice, the undersides had see through insulation.

Lots of old parts survive, vintage radios get scratches or wood worm and the innards are sometimes kept. I thank those hoarders with all my heart, lol 

The wooden bread bin was around £20 from a well known retailer, designed for a rustic look.

The coil tap switch is shown here, all well made and expensive at the time I expect. I made a plastic strip for the connecting terminals at the rear and used brass nuts and bolts, not Philips screws (too modern) trying to get the feel of a period build. I'm not sure how far back curved bread bits go back but I remember having one in stainless steel for a wedding gift, only to be confiscated by the DTI in a studio raid once when I had used to as a screening can for two tape decks, lol

  This photo just shows me placing parts inside so they could be  seen from front and also gave enough room for the 18 SWG copper wiring. I drilled 2 holes in left side for speaker wires, but all the others were contained at rear inside.