A transverter is a transmit and receive converter that enables a transceiver operating on say the HF bands to be used on one or more of the VHF bands or vice versa. The following block diagram shows an example of a transverter using a bi-directional mixer with additional transmit receive switching and RF/IF amplification. The changeover switches are left to the builder but may be passive in the form of miniature relays (including reeds) or electronic in the form of diodes or analogue switches.

Key:

BPF - Band Pass Filter

DBM - Double Balanced Mixer

IF - Intermediate Frequency

Rx - Receiver

Tx - Transmitter

Notes:

• This arrangement is applicable to almost any frequency range and is intended for use in a low impedance environment. The RF to IF to ratio should not exceed 10:1 in order to simplify the problems of image attenuation.
• Transmit/receive changeover switches are shown in the receive position. The switches may be relays or PIN diodes as preferred by the constructor.
• If the above circuit is only to be used on receive then leave out the switches and transmitter parts.
• Depending on the switch contact material it may be necessary to wet the contacts by passing a few milliamps of DC current through them to ensure reliable contact.
• The IF preamp must have low noise, 50ohms input and output impedance, high dynamic range and a gain of about +9 to +12dB.
• A low loss roofing filter may follow the diplexer only as long as it provides a 50ohm impedance at all frequencies. Design information on diplexers and roofing filters is here.
• The Rx preamp is optional for the HF band use but required for 50MHz and above and could be switched in and out of circuit.