The Hermes-Lite Project

The Hermes-Lite project aims to design and market a software defined radio transceiver that directly samples the antenna with an analog to digital converter, is completely controlled by Ethernet, and costs about USD 200. It is contained on a single 10x10 cm PCB. The standard enclosure is 10x15 cm and the extra space is meant for filters, transverters and other add-on boards. The Version 2 hardware includes a 5 watt push pull MOSFET amp as well as a 100 mW low power output. Since the FPGA and the digital up/down conversion is on-board, a sound card is not used for radio samples, and is only used for the microphone and for playing radio sound.

Filter Board by James Ahlstrom, N2ADR

The Hermes-Lite 2 is ready to use at 100 mW output or at 5 watts output as an exciter for a subsequent RF amplifier. But to use the 5 watt amp as a complete QRP rig, it needs transmit low pass filters. I designed a 5x10 cm filter board that clips to the main board and fits into the standard enclosure. It has transmit low pass filters for 160 to 10 meters, and a 3 MHz high pass filter for receive. The filter board is automatically controlled by the Hermes-Lite main board. The filter is currently being tested, so is not yet available.

Here you can see a photo of the board, and the schematic.

January 2, 2018. More to follow...