This is the unexpurgated, pre-edited version of the article `Improved Anode-Circuit Parasitic-Suppression For Modern Amplifier-Tubes` that appeared on page 36 in the October 1988 issue of QST. A more recent treatment of the subject appeared in the September and October 1990 issues of QST. The article is titled `Parasitics Revisited. ` The purpose
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in publishing this manuscript is to allow the reader to see whether on not QST is influenced by advertisers. To do this, open up a copy of the Oct. 1988 QST, and compare. Anything in parenthesis is not part of the manuscript text. The information in parenthesis was added later. The traditional copper-inductor/carbon-resistor anode [plate] parasitic-suppressor has been used in vacuum-tube amplifiers for at least 50 years. The earliest record of an anode parasitic-suppressor that I can locate was in a transmitter that was built in the early 1930s by the (Art) Collins Radio Company. (In late 1990, I was made aware of some interesting information on anode-circuit VHF parasitic suppressors in the 1926 Edition of The Radio Amateur`s Handbook. This information was inexplicably omitted from post-1929 editions. Info provided by Dave Newkirk, WJ1Z) Much of the reason for Art Collins` early success can be attributed to the fact that he, almost alone, understood that where RF is concerned there is no such thing as a zero-potential "ground" and that any wire or strap was a capacitor-inductor VHF tuned-circuit as well as a conductor. He understood that an "RF-choke" acted like a short-circuit at certain frequencies and that sometimes a resistor would make a better RF-choke than an RF-choke! Because he understood these "RF secrets", he was the first manufacturer to build a transmitter that: worked on all frequencies up to 14. 5MHz, was...
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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