10 GHZ Transverter

A number of amateur radio operators have begun their journey in the 10 GHz band using surplus microwave transceivers manufactured by M/A-Com, commonly referred to as "White Boxes." These devices can be modified to function as transverters, which convert signals from an amateur VHF transceiver to the 10 GHz band. In this context, the VHF transceiver serves as the intermediate frequency (IF) transceiver. The modification process typically involves removing the original components from the enclosure and retaining only the main tray with the essential parts. One specific White Box was partially modified by the late Dr. Arthur Schulman, VE3ZV, for use by Steve, VE3TFU, who later passed it on to another operator. Modifications to the RF circuitry were completed by Steve, VE3SMA, who has documented his process in a paper available on the website's Downloads page. For this particular unit, the receive filter in the transverter module was removed, and a new receive connector was added, while following the general modification procedure. Key components for amateur use include the RF unit, local oscillator (LO) unit, and linear regulator board, as illustrated in Figure 1. To prepare the unit for operation, various enhancements were made to simplify wiring and external controls. A printed circuit board (PCB) was designed for control and sequencing, accommodating all circuitry and wiring within the available space. The design was compatible with the Yaesu FT-817 as the IF transceiver. Originally, the White Box was intended for fixed installations with an AC power supply, but modifications were made for portable battery operation, including the addition of DC-to-DC converters for necessary voltages. The tray handle was utilized to install switches and connectors, including a power switch, IF connector, and fuseholders. To streamline setup and maintain an uncluttered workspace, the IF transceiver was powered from the White Box, incorporating a fuse, polarity protection diode, and power cable from the DC distribution board. An interface was necessary for switching IF signals between the transmit and receive modes of the transverter and controlling its operation. Careful sequencing was required for power, IF, and transmit/receive signals to prevent damage to the transverter circuitry. The developed circuitry for switching and control was based on Steve, VE3SMA's previous work. The control board schematic is depicted in Figure 2. The sequencing process must consider the RF relay characteristics to ensure that switching occurs without RF signals present, necessitating immediate switching before transmission and a brief wait before switching back to receive mode.

The design of the White Box transverter system incorporates several essential elements to ensure reliable operation in the amateur radio domain. The RF unit is responsible for amplifying the signals, while the local oscillator generates the necessary frequencies for mixing with the incoming VHF signals. The linear regulator board stabilizes the power supply, ensuring consistent performance across various operational conditions.

The choice of components and layout within the PCB is critical for minimizing interference and ensuring efficient signal flow. The integration of DC-to-DC converters allows for flexibility in power management, enabling the system to operate effectively in portable settings where battery power is the primary source. This adaptability is vital for field operations, where power supply options may be limited.

The implementation of an interface for the IF transceiver is designed to facilitate seamless switching between transmit and receive modes. This interface must be robust enough to handle the rapid changes in signal states while preventing any potential damage to sensitive components. The careful sequencing of operations helps to mitigate risks associated with RF relay switching, ensuring that the system remains functional and reliable during operation.

Overall, the modifications and enhancements made to the White Box transverter reflect a comprehensive approach to amateur radio design, prioritizing ease of use, operational efficiency, and adaptability to various environments. The documentation of the modification process serves as a valuable resource for other operators looking to undertake similar projects, fostering a collaborative spirit within the amateur radio community.A number of ham radio operators have made their start on the 10 GHz amateur band using commercial-surplus microwave transceivers made by M/A-Com. These units were originally built in white-painted metal enclosures and are known as "White Boxes" They can be modified to operate as transverters (transceiving converters) to convert the signals from an

amateur VHF transceiver to the amateur 10 GHz band. The VHF transceiver is known as the intermediate frequency (IF) transceiver in this application. Modifying a White Box for ham radio service usually involves removing the equipment from the box and keeping just the main tray containing the desired parts. My White Box had been partly modified by the late Dr. Arthur Schulman, VE3ZV for use by Steve, VE3TFU. Steve generously gave it to me, and another Steve, VE3SMA kindly completed the modifications to the RF circuitry before I received the unit.

Steve has modified other White Boxes and his paper describing the process is on the Downloads page of this website. For my White Box, he removed the receive filter in the transverter module and added a new receive connector but otherwise followed the procedure in his paper.

The main parts of use in ham service are the RF unit, the local oscillator (LO) unit and the linear regulator board as shown in Figure 1, a photo of the unit as Steve received it. I had to do the following things in order to get it on the air : My goals were to keep the wiring within the White Box simple, to make it easy to build.

To make it easy to operate, I wanted to make the external control, DC and RF wiring simple as well. As a result, I decided to design a printed circuit board for the control and sequencing. Designing the pcb to handle much of the internal and external interconnection allowed me to fit all the circuitry and wiring in the space available on the White Box tray. The circuitry was designed to work with a Yaesu FT-817 as the IF transceiver. The White Box was originally designed to work in a fixed location, with an AC power supply providing several different supply and bias voltages.

Since the ham radio version is generally used for portable operation with battery power, Arthur had added two DC-to-DC converters to create the necessary supply and bias voltages from the battery voltage. I used some perf board to re-mount the -5 v bias supply and added DC distribution terminal blocks. The tray handle seemed like a good location for switches and connectors, so I installed the power switch, the IF connector and a panel to hold the fuseholders for the transverter and the IF transceiver.

To make system setup easier and to keep the operating area as uncluttered as possible, I powered the IF transceiver from the White Box, with a fuse, polarity protection diode and power cable from the DC distribution board. An interface is required between the IF transceiver and the transverter to switch the IF signals between the transmit and receive portions of the transverter and to control the operation of the White Box.

Switching of the power, IF, and transmit and receive signals must be carefully sequenced in order to avoid damage to the circuitry of the transverter. This circuitry must detect whether the IF transceiver is in transmit or receive and: As described in his paper, Steve, VE3SMA had developed circuitry for switching and control while modifying another White Box.

I used his circuitry as a basis for mine. See Figure 2 for the Control Board schematic. The sequencing of the transverter must take into account the characteristics of the RF relay used to switch the transmit and receive signals to the antenna: because the RF relay contacts are not built to switch while transmit signals are present, the relay must switch while no RF is present. This entails switching it instantly when going into transmit, before any RF is present, and waiting briefly before switching it when returning to receive.

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