YO4HFU
50 &70/28MHZ Transverter


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


Download Schematic

Block Diagram Dual Transverter
Transverter 50MHz/70MHz to 28MHz
Low Pass Filter 50MHz
Low Pass Filter 70MHz

Bibliography: 50MHz version, 70MHz version, 50MHz Italy Kit (interesting TX amplifiers with negative feedback)


PCB
PCB-bottom
PCB-components position
Mixer

Photos
Transverter 6m
Transverter 4m
Front Panel

Board

 

This transverter I started in 2010 and was completed after 4 years, free time problem.. Basically is OE9PMJ design adapted also for 70MHz/28MHz use.
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. Better is to use separately TX power board (shielded). Only one power transistor was used, one more stage can be found on the PCB (bypass or edit PCB file).
Gain distribution must be chosen with care for 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 suppressed carrier (SSB) even if the original signal have good quality, this happen when TX mixer or other stage is overloaded.

 


 

 

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