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Hermes - A DUC/DDC Transceiver

Hardware block diagram. Click to enlarge.

Project Leader: Kevin M0KHZ

Update 11 July 2012

Hermes is a single board Digital Up and Down Conversion (DUC/DDC) full duplex HF + 6m multi-mode transceiver.

It is basically the Mercury, Pennylane, Metis and Excalibur (less TCXO) boards rolled into one PCB. The board communicates to an associated PC via 100T/1000T Ethernet.

Hermes has the following features and facilities:

  • Continuous, uninterrupted, receive coverage from 10kHz to 55MHz.
  • Supports Real-Time display of entire spectrum from 0-55MHz (with suitable PC software)
  • Supports 7 fully independent receivers (sharing the same antenna - and with suitable PC software)
  • Each receiver can display 48/96/192kHz of spectrum
  • Blocking Dynamic Range (ARRL Method) - no detectable gain compression below ADC overload
  • High performance receiver – same specifications as the HPSDR Mercury receiver (ie Dynamic Range typically 125dB)
  • Transmit and receiver image rejection > 110dB
  • Full duplex operation, any split over entire 160m to 6m range.
  • Transmitter two-tone 3rd order IMD of -50dBc on 20m @ 400mW output
  • 500mW RF output on 160 – 10m amateur bands, 350mW on 6m
  • Built-in high performance preamp, with a noise floor typically -135dBm in 500Hz
  • Software-selectable 31dB input attenuator in 1dB steps
  • FPGA code can be updated via the Industry Standard TCP/IP network Ethernet connection
  • Seven user-configurable open-collector outputs, independently selectable per band and Tx/Rx (for relay control, etc - with sequencing via PC code)
  • Separate open-collector PTT connection for amplifier control, etc, with sequencer
  • Microphone PTT jumper-selectable from tip or ring connection
  • Bias for electret microphones via jumper
  • Four user-configurable 12 bit analogue inputs (for ALC, SWR etc)
  • Three user-configurable digital inputs (for linear amplifier over temperature, etc)
  • Can operate from a 13.8v DC supply or +12v and +5v supplies
  • Jumper selected in-built low noise and high efficiency switch mode power supply designed by Kjell Karson,LA2NI – less than 600mA (receive - one receiver) from a 13.8V supply
  • I2C bus connector for control of external equipment
  • Full QSK operation (performance dependant on associated PC and control software)
  • Low-level transmitter output for transverter use via user-selectable output attenuator
  • Stereo audio outputs at line and headphone levels
  • In-built 1W stereo audio amplifier for directly driving speakers
  • Direct, de-bounced connections for a Morse key (straight or iambic) and PTT
  • Low phase noise (-140dBc/Hz @ 1kHz at 14MHz) 122.88MHz master clock,which can be phase-locked to an internal 10MHz TCXO or external frequency reference
  • Direct ribbon cable interface to Apollo 15W power amplifier, low pass filters and automatic ATU or ANAN-10 10W power amplifier and low power filters
  • Industry Standard TCP/IP network Ethernet interface supports static, APIPA or DHCP IP address
  • Hermes responds to ping and ARP requests and auto senses network connection speed
  • PCB is 160mm x 120mm, 8 layers

Apollo is a combined 15w PA, Low Pass Filter bank and Automatic ATU. The Apollo project is led by Kjell Karlsen LA2NI.

Hermes can be used as a Vector Network Analyzer: VNA

Hermes and Apollo in enclosure - photo copyright Kjell Karlsen 2010.

Update 7 August 2011

The primary PCB layout team member of Hermes, Abhi has a blog on Hermes at . --KV0S, Dave

Update 7 July 2011

A prototype board has been built and tested. The board is fully functional and meets or exceeds the performance of the Mercury/Penelope/Metis/Excalibur boards the design is based on.

Some minor board layout issues are currently being addressed and a pre-production layout is presently being prepared. The KD5TFD and W5WC versions of PowerSDR(TM) as well as KISS Konsole have been modified to provide native Hermes support.

Ken, N9VV, has a lot of information regarding Hermes on his web site here

(click for larger image) photo courtesy Abhi Arunoday

There are also the Hermes Board Build Notes

Update 2 December 2012

A useful website for Hermes users can be found at by Dick K9IVB. --KV0S, Dave

There are the Hermes Board Build Notes as well.