13cm TRANSVERTER

transverter front

Front view. The status LEDs are visible. A solid READY LED (green, top) indicates control signals between radio and transverter are OK, blinking indicates an unconnected status. TX LED (red, middle) turns on when in transmit. The covered hole at the bottom is reserved for future use.

This 2320MHz transverter is based on W1GHZ’s board. The small PCB soldered beneath the transverter board is an RF synthesizer based on the SI4133 chip. It accepts an external 10MHz signal from my GPSDO. It produces a LO of 1890MHz so the IF is in the 70cm band. Since we don’t need to multiply the RF synthesizer output, two of the pipe cap filters are not needed anymore. On the top of the transverter board at the freed space a small board handles the IF paths between transmit and receive (W1GHZ’s board has only one IF connector and the mixer has to be driven with 0dBm maximum, so an attenuator has to be thrown into the TX path so as to be used with 0.5W coming from the FT-817 ) using PIN diodes (BAR50-02V). An external board utilizing the RFMD SZA-2044 amplifies the output at about 700mW. Another board utilizing an OMRON G6Z-1F-A relay handles the switching between TX and RX. There is internal provision for a high power amplifier in the future. The last board is the sequencer which is built around an ATMEL ATtiny2313 microcontroller. It is designed to take advantage of the TX inhibit pin in the FT-817’s  ACC connector. This effectively acts as a PTT input to the 817. The 12V voltage output from the 817 is also monitored and in the absence of it the transverter goes into ‘safe mode’. The cables are not cut to their final length yet!

transverter back

Back view. From left to right: IF connector (BNC), 13cm connector (N type), 10MHz external reference connector (SMA), control signals connector (8 pin mini-DIN), +12V supply connector.

transverter top

From left to right: Sequencer board, transverter board, relay and PA boards (just visible).

transverter front inside

The TX/RX relay and PA board.

transverter bottom

Bottom side of the transverter’s PCB. The RF synthesizer board is visible. It utilizes a SI4133 which is programmed by an ATtiny13 microcontroller to produce a 1890MHz LO with 10MHz external reference. An ERA-2 amplifies the output (at about +10dBm) which is then fed to the mixer using a small length of RG-402.

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