The goal was to convert this radio for operation on the 70cm amateur radio band. This was unsuccessful as the VCO will not oscillate at the right frequencies for 70cm operation (the VCO control voltage bottoms out before the VCO gets anywhere near the 70cm band). The VCO is too small and it is too hard for me to trace the multilayer board tracks (
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I do not have a service manual for this radio) so I can not change the frequency determining components of the VCO. Please note that the antenna was removed from this radio and replaced with a dummy load for these experiments. However, all is not lost. This project was a valuable learning experience and with any luck, the tools that I produced in the process (essentially a crude logic analyser) will be able to be used to reverse engineer other serial PLL control protocols. I was unable to find a datasheet for the AN6311NFA, however, I was able to find data on two similar ICs made by the same manufacturer. This, combined with my oscilloscope, allowed me to identify the serial control lines on the AN6311NFA. One board with an ATtiny2313 microcontroller (clocked at 18. 432 Mhz) and an ST232 RS232<->TTL level converter was constructed. One complication encountered was that the PLL was supplied from a 3. 3V DC power supply, when spying on the serial comms to the PLL this is not a problem as 3. 3V is enough voltage to register as a logic high on the tiny2313`s input pins (when the tiny2313 is supplied with 5v). However, when driving the PLL, care must be taken to limit the voltage on the PLL input pins to 3. 3V or less, I did this by using pullups between the PLL input pins and the radio`s 3. 3V rail and by using the tiny2313`s outputs to pull the PLL input pins low when a logic 0 was required. Three different firmware programs...
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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