The Mainline ST-5 was originally Introduced in the RTTY JOURNAL in May, 1970. It has rapidly become one of the most popular demodulators for RTTY. As back issues have been un available for some time, the original article is being reprinted. For those interested in 100 speed, change the 0. 068 capacitor on the input to the slicer to a 0. 039. A 741 m
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ay be used for the slicer if desired, in which case the 220 pf, 0. 005 Mfd. , and 1. 5K components are left off, as the 741 is internally compensated. Regulated voltage has been added, as shown. Keep in mind also that prices quoted were current at the time the article was originally written. Both Hal Communications and PEMCO, and possibly others, offer boards, components, kits and ready-to-use ST-5 units. Many newcomers to RTTY have complained that a current yet simple de modulator hasn`t been published for them to build. The W2PAT unit in the ARRL handbook is nearly 15 years old. In 1964 an attempt was made to replace the W2PAT design with a modestly priced updated unit, the TT/L-1. This design. together with the subsequent TT/L-2 is now the standard of the serious RTTY enthusiast. However, the original goal was missed by a country mile, since the TT/L-2 costs over $160 just for parts and has l4 tubes. The ST-3 was a successful solid- state design that introduced integrated linear operational amplifiers to RTTY. It was still moderately complex, however, and fell short of the goal to supply the beginner with something that could be built in a few hours. While developing a unit based primarily on ICs to replace the TT/L-2, a very simple modulator with great potential was developed: the ST-5. As with any simple circuit, the cost of the power supply is out of proportion with the rest of the unit. At 1970 prices the ST-5 costs...
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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