0V0 MEDIUM WAVE RECEIVER
WITH A BATTERY TUBE
(1964)

KLIK HIER VOOR DE NEDERLANDSE VERSIE


Televisions and radio's with tubes.

Radio!
All those beautiful parts and then finally the sound of a self-built radio, fantastic! I had made already a transistor radio, but now a radio with a tube had to be made! Radio electronics was my hobby! In the attic was the table where I was allowed to solder. Cutted wires from electronic parts in my socks, I was already totally used to it!


We played in unheated bedrooms. With ice on the windows
as double glazing did not exist and only living rooms were heated!
And we had real winters with much snow and ice!
And it was cold, we had real winters! Only living rooms were heated. So we played in unheated ice cold bedrooms. With ice on the windows as double glazing did not exist! But we have survived the harsh winter of 1963 without any problems! At that time, we were not dependent on electricity. If there was a power failure, we simply took a candle, the fire kept burning. And we did not have a fridge, we had a basement. And every evening, the water was cut off to prevent frozen water pipes.
We played with Lego, Meccano, cars and electric trains. And sometimes we were allowed to play with the radio at Peter's home! Those morse stations on the longwave, looking at those tubes, great! I got a book about radio and of course I had to build a radio with a tube!


The applied tube DL92.


The ATOM receiver was my first radio with tubes. It was a small 7 pin tube for use with batteries. The anode voltage was 13.5V (3 flat batteries in series) and the glow wire voltage came from a fat 1.5V battery.

The tube radio "ATOM" from the book "Boys Radio" was built.
The ATOM receiver was my first tube radio. With a small 7 pin battery tube. It is a 0V0, so only a detector tube and no RF amplifier and no LF amplifier. The construction consisted of Amroh aluminum chassis parts. And the very well-known 402 coil was used, with which the whole medium wave could be received. For the tuning I used such a well known "brown" mica variable capacitor.
For an optimal match, the antenna is connected to a tap of the coil. The tube is connected to the top of the tuned circuit. Grid detection is used, the grid-cathode space acts as a detector. The grid can also receive a negative bias due to the grid current that always flows when the cathode-grid voltage is close to 0 volts. Here it is a little difficult because of the voltage that is caused by the filament voltage. Different parts of the cathode have different voltages.
The tube does not only amplify the detected low-frequency signal, but also the high-frequency signal. From the anode, a part of the amplified high-frequency signal is fed back to pin 5 and 6 of the coil 402. By means of the potentiometer R1, the part of the RF signal that flows via the coil or via the potentiometer can be adjusted. And that is how the regeneration control works. For amplitude modulation it has to be set to the level that it does just not generate. Via R5 (probably a blockade for the high-frequency signal), the detected low-frequency signal by the tube flows to the crystal phone.
Unfortunately, the adjustment of the regeneration was not really good. You could not set it to the level that it just started to generate, because the receiver began suddenly to oscillate. But it had still a good medium wave reception. Maybe I just needed to change the polarity of the filament, at that time, I did not have the idea to try that out.
Early in the morning with my bare feet on the ice cold linoleum I was listening to the extended weather forecast and the prices of vegetables. Great when you hear that with your own receiver! With the curtain rail as an antenna and the bed as earth. And in the evening there were many foreign broadcast stations! That fading, wonderful!
Cold red toes, during many hours I was listening to all those medium wave transmitters. But that battery for the filament voltage, what was that quickly empty! A considerable drain on my pocket money! Unfortunately, I did not use this receiver very long. Accidentally I reversed the 1.5V battery and the 12V battery connections. A very short flash inside the tube and it was dead. I did not have money for a new one...


The famous Amroh mucore-402 coil wass used in this design.
(Picture from the website of Piet Blaas)
The anode voltage was 13.5V (3 flat batteries in series).


Boys Radio!
I did read in this book during many hours!
The design of this receiver was found in this book.

Life was simple.
Life was simple. Almost everyone had a radio with tubes tuned to the medium wave. Many also had a black and white television with tubes and only two channels, Netherlands 1 and Netherlands 2. On Wednesday and Saturday afternoon we were allowed to watch television. A program of one hour for children. And some had a record player. All those glowing tubes were wonderful to see! You had to pay tax for the use of a radio and television, unthinkable nowadays!


Almost everybody had a radio with tubes.

BACK TO INDEX PA2OHH