The next job is the LNA transistor replacement, but the trouble is repeated already within next contest. Such problem is usually result of unsuitable time sequence of switching between receive and transmitting, where due to different delays (for example by mechanical movement of relay parts) may happen conflict between beginning of transmission (e. g. by push down of key), although the complete transmitting chain
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is not ordinary switch on yet, or in opposite within switch down from TX to RX, when antenna relay already going to RX, but due to another PA relay mechanical delays the TX is not calm down yet and last dot of TX CW power (or roger beep) may still be observed. Result of such unpredictable transition status is not enough isolation between RX and TX chain in the antenna relay (because this relay is just moving) and the peak of power transported across the switching antenna relay may easy destroy input transistor of LNA or even receiver front end. Even in case, when different delays in our TX chain were adjusted properly and such trouble was not observed for years, change of transceiver or transverter may create change of the whole chain delay and when we want (for example) use older PA together with new transceiver (which has not mechanical, but PIN diode RF switch inside), or even when the SW delays of transceiver is setup to QSK, the trouble of LNA damage or in the worst case even antenna relay may be destructed. Substantial part of solution of such unlucky situation is an installation of appropriate time sequencer into each final stage PA, which is used. Each important parts of TX/RX chain will be then controlled in certain predicted time steps, what ensures, that the above described conflict between TX and RX ways will be eliminated. And because such additional control circuit shall be installed into any present PA, it...
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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