At some point every ham working with FM radios has need to do some tuning of the transmitter and receiver. If you are like me and lucky enough to have professional test equipment, this task is easy. If you don`t have access to professional equipment, you just have to be a little more clever. Note that a good deal of what I have to say here applies
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equally to the popular Mitrk and Maxar Motorola radios along with most other crystal controlled amateur and commercial radios. The basic principles are the same. If you become confused by what I have to say about local oscillators, mixing and "IF strips, " I strongly recommend reading about those subjects in the ARRL handbook. The knowledge you will gain you will find extremely valuable in the future. Setting the frequency of both the transmitter and receiver in a crystal controlled radio is pretty straight forward. Frequency counters that work on the 2 meter and 70 cm bands are common place and affordable. A decent counter in calibration gives you a good test equipment foundation that is hard to beat for the cost. With a counter transmitter frequency alignment is pretty simple and straight forward. First off allow all of your equipment (this includes the radio to be serviced) time to warm up so all of the oscillators are stabilized. I would wait at least 20 to 30 minutes. Make sure that YOUR test equipment is in calibration! It sure does not hurt to run a calibration check of your own gear before working on something as sensitive as a 9600 baud data radio or a repeater. If you are using a ham type counter keep in mind that most inexpensive counters do not have crystal oven. This means that it is very easy for your counter to be off frequency and lead you astray. If you are lucky, your counter will use a time base crystal...
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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