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 boards rolled into one 120 by 160 mm PCB. The board communicates to an associated PC via 100T/1000T Ethernet.

Hermes has the following features and facilities:

  • Uninterrupted coverage from 50kHz to 5%MHz
  • 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
  • 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 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 analog 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 Alex Antenna switch, HPFs and Tx LPFs
  • Ethernet interface supports fixed, APIP or DHCP IP address
  • Hermes responds to ping and ARP requests, auto senses Ethernet cable connection and connection speed
  • PCB is 160mm x 120mm, 8 layers

More detail are available at the Hermes Wiki Page.


Dues to cost of production, the ordering process will be somewhat different than any previous HPSDR projects. Hermes will be produced in a single production batch whose size is based on the number of orders places on this page prior to July 25. The number of orders placed up to and including July 25 will be the production quantity. No extra A&T Hermes will be produced by TAPR.

Credit cards will be charged for the cost of Hermes plus estimated shipping once the order quantity reaches 250.
Shipment is expected to be as early as September 6th or as late as October 15th.

$ 895 US for members of TAPR
$ 940 US for non-members
+ shipping/handling if applicable.