Some of us still get a great buzz out of home construction.
Sasha 4L4P is an avid constructor and has recently built a VFO and has sent the following information about his work.
In today’s world, the demand for up-to-the-minute transceivers is increasing day by day. These new technologies offer modern approaches that have replaced classical frequency generation systems. But if we return to the classics for a while, we will notice that they had their own beauty and features. Presented in this post is a variable frequency oscillator (VFO) built by one of the Georgian radio enthusiasts, Sasha Chakvetadze, 4L4P.
While building it he had to consider the difficulties involved, which are the main reason why we moved on to more modern solutions. When working on an analogue 9-band VFO (Variable Frequency Oscillator), there were several challenges which he had to consider such as frequency stability. Temperature changes and power supply fluctuations can also cause frequency drift, affecting stability.
Component tolerances:Variations in components like capacitors and resistors can lead to inaccurate frequencies.
Harmonics and Interference: Analogue VFOs may generate unwanted harmonics or spurious signals, interfering with other channels.
Power Supply Noise:Power supply instability can introduce unwanted modulation or noise into the signal.
Tuning Issues:Mechanical or electronic tuning may not always provide precise control over frequency, leading to non-linearities.
Phase Noise:Analog VFOs are prone to phase noise, which can reduce signal quality.
Temperature Sensitivity:Temperature variations can affect component performance, requiring compensation.
Mechanical Stability: Rugged construction contributes greatly to stability and can be seen in Sasha’s solid, excellent workmanship throughout.
To overcome these challenges, the use of high-quality components, careful circuit design, and feedback mechanisms can help improve performance and stability.
The schematic diagram follows the photographs of the finished VFO.
