The performance of the 80 meter CW transceiver using the phase method for side band suppression is very good. Construction was easy with all good obtainable standard electronic components and without the expensive or complex crystal filter. Almost nothing is heard on the unwanted side band. Therefore I had the plan to make a four band version to s
Click here to download the full size of the above Circuit.
ee how the performance of the phase method for suppression of a side band is for other amateur bands. But it had a lot of disadvantages. No 30 meter band, some frequency drift, no accurate frequency read out, a double side band direct conversion receiver, spurious emissions did not comply with the current limits. There were a lot of problems with 50 Hz hum due to the audio transformers and 88 mH inductances in the filters. Therefore, it was time for a restoration. I decided to dismount all the old printed circuit boards and keep them as a memory. Only the enclosure is used again, the damaged paint due to the intensive use in the shack and mobile while sailing is left in original state. It should become a four band version of the 80 meter band CW transceiver with the phase method used in the receiver. Adding the 30 meter band and also a simple frequency counter were the most important wishes. The antenna signal is routed through a RF attenuator potentiometer to the four preselector circuits. It was easier to make four different RF amplifier than one with input / output switching circuits. The RF signal is split into two signals that are shifted 90 degrees out of phase (one plus 45 and one minus 45 degrees). Both are mixed to audio frequencies. The two audio signals are again shifted 90 degrees out of phase (again one plus 45 and one minus 45 degrees). When we add the two signals, the signals of one side band are in phase,...
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.....
characters left: