YO4HFU
50 &70/28MHZ Transverter


click to enlarge

 

 

Power output @ 13,8V: 50MHz=15W, 70MHz=10W, second harmonic < 65dBc.
Single N connector for antenna, suitable for a dual band Yagi...hi!


Download Schematic
Schematic...under construction...
Low Pass Filter 50MHz
Low Pass Filter 70MHz

Bibliography: 50MHz version, 70MHz version, 50MHz Italy Kit


PCB:
PCB-bottom
PCB-components position
Mixer

PHOTO:
Transverter 6m
Transverter 4m
Front Panel

Board

 

This transverter I started 4 years ago. I avoided using common blocks for 50 & 70 MHz. In the future I would never use a single board for low signal and power amplifier. Is very difficult to avoid self oscillation. All amplifiers stages have high gain at this frequencies.
Gain distribution must be chosen with care especially in the TX channel.
Attention should be paid to the dynamic range of the amplifiers. They have to work linear and not compress the original signal. There may be a low rejection of the remaining carrier even if the original signal have good quality. Limitations may reduce difference between a low signal and a high amplitude signal (power peaks). Output signal level must be directly proportional to the input...dB versus dB :)
Without spectral analyzer, it was impossible to get good performance.

 


 

 

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