RF Cafe visitor David M. wrote to ask that I scan and post this article from the January 1963 edition of Popular Electronics. It is an article written by Philip Hatfield, of the Receiving Tube Department of General Electric that describe a very simple design that uses a ` compactron ` vacuum tube, which consist of two triodes and a pentode.
Click here to download the full size of the above Circuit.
The compactron was sort of a vacuum tube version of the multi-amplifier integrated circuit of today. They are still available for purchase on eBay for a couple bucks each. MOST of today`s short-wave receivers are truly sensitive and reliable devices, but they are also rather complex and expensive for the beginner to construct. Here`s a simple receiver, using one compactron tube, that will give you long-wave, broadcast-band, and short-wave reception. If you are considering putting your first receiver together, this one is for you. If you, have an amateur-band-only receiver, this unit will fill in some of the "holes" in the spectrum. Finally, if you already have a general-coverage receiver, this set will make a good "auxiliary" to tuck a way on a corner of the desk just in, case your "big" one quits. Use of a compactron allows a lot of receiver to be contained in a small box without undue crowding. the frequency range covered is from 250 kc. all the way to 16 mc. ; and, since plug-in coils are used, it`s possible to extend the range in either direction. Plenty of headphone volume is provided, and many signals will operate the built-in speaker in a very satisfactory manner. The Circuit. The 6AF11 compactron contains two triodes and a pentode. One triode is used a regenerative detector, the other as an audio voltage amplifier, and the pentode as an audio power amplifier. Plug-in coils containing primary (L1), secondary (L2),...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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