Syllabus Sections:-

Down-converters

4q.1 Understand that VHF and UHF operation can be carried out by using down converters and transverters ahead of HF equipment.

The use of down converters and transverters ahead of HF equipment was popular until about the late 70's.

Down converter

A down converter take a signal from a band higher than HF ie higher than 30MHz say 2m and converts it down to an RF signal in the HF band range. This is achieved by mixing the 2m signal with an Intermediate Frequency to give an output on 28-30MHz.

The signal that came in on the 145MHz band is now being heard on a receiver tuned to the 28MHZ band and so long as the HF receiver can receive the mode of the signal is will be heard just as if the receiver could receive 145MHz directly.

The Transverter

Whilst the down convertor only dealt with the converting down of a signal the transverter could not only achieve the conversion down but also the conversion up. This then enable a radio amateur with only an HF rig to transmit and receive 2m.

Where is such equipment used to-day ??

It is not used in the lower frequencies but the microwave frequencies commonly down convert to 2m or 70cms when receiving satellite communications and sometime a transverter is also used.


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