An oscillator-only transmitter sounds like the simplest possible means of getting on the radio air ”until you consider the challenges it presents as part of the system that is a transmitting and receiving station: The problem of an adequate crystal-controlled transmitter for the newcomer who wishes to come on the air for the first time on c. w. ha
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s never been very effectively solved for the amateur who has but a small amount of capital to invest in the first rig. The majority of the beginners now coming on the air use some type of a keyed crystal oscillator coupled directly to the antenna system. We all well know the results of this kind of operation. If the crystal is anything but the very best and most active type, the arrangement is capable of almost no usable power output. If the crystal happens to be an especially active one, it will be possible to obtain a respectable amount of power output but bad keying chirps are likely to be present, dots are very often not present if rapid keying is used, or the rig may frequently become temperamental after having lain idle for a few hours or days and refuse to key at all until it is retuned. Then, if the crystal does operate well and key cleanly, there is always the temptation to raise the plate voltage to increase the power output. This may be fine until the antenna accidently or intentionally becomes uncoupled some fine day with the result that we will usually be in the immediate market for another crystal "as close as possible to the frequency of the last one. " ”Jack Rothman, W6KFQ, "The Newcomer`s Special, " Radio, October 1938, pages 38 40 and 66. The usual beginner`s transmitter is built around a single tube, following the premise that more than one stage will make the first step too complicated or too expensive....
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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