Construction of a radio telephone integrator and created my first radio phone / repeater. I had been playing with electronics and radios since that first receiver I had built back in 1973. With that simple receiver and a random wire antenna I had discovered the world of SWL and Amateur radio. Now with Leo`s inspiration I assembled the components for a full duplex radio telephone system using
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29 MHz for my input frequency and 158 MHz for my output. This simple system which used circuits found in the ARRL handbook enabled the operator to send touch tone command from a radio system in his or her car back to the base station and access the land line to make and receive phone calls. In these first few photos above you can see Leo`s hand written system schematics for the radio phone integrator. In the next three photos you can see my system with the commercial VHF radio which was the transmitter and the ham radio used as the receiver. In the photo to the left I was an old VHF radio running about 15 to 20 watts. The photo to the right shows the system after an upgrade with a %100 duty cycle VHF radio and power amplifier running about 95 watts. With this initial system Leo and I had good radio phone coverage all around northern Rhode Island and into parts or southern Massachusetts. As we developed our little "network" we each ran a full duplex system and shared each others nodes dramatically increasing our range. We both used the same system output frequency with different input frequencies and the only real trick was to figure out just who`s phone was ringing when one of the systems would activate! These next four photos above show my ham station as it grew and evolved over the next few years. Most of the items in my shack were kit`s, I built the HK-232 packet radio controller and the Code-Star CW Decoder. All the...
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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