Difference between revisions of "HERMES"

Revision as of 23:14, 7 July 2011

Hermes - A DUC/DDC Transceiver

Hardware block diagram. Click to enlarge.

Project Leader: Kevin M0KHZ

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

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

Hermes has the following features and facilities:

• Uninterrupted coverage from 50kHz to 54MHz
• Transmit and receiver image rejection > 110dB
• Full duplex operation, any split over entire 160m to 6m range
• Future expansion possible to eight independent receivers using the same antenna
• 500mW RF output on 160 – 6m amateur bands
• Built-in high performance preamp, with a noise floor typically -135dBm in 500Hz
• Software-selectable 31dB input attenuator in 1dB steps
• High performance receiver – same specifications as the HPSDR Mercury receiver (ie Blocking Dynamic Range typically about 125dB)
• 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 analogue inputs (for ALC, SWR etc)
• Three user-configurable digital inputs (for linear amplifier over temperature, etc)
• Optional in-built switch mode power supply – less than xxxmA (receive) from a 13.8V supply
• I2C bus connector for control of external equipment
• Full QSK using the Kiss Konsole software, since digital signal processing is not used in the controlling PC for CW carrier generation
• Low-level transmitter output for transverter use (0dBm) as well as 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
• 122.88MHz master clock, which can be phase-locked to an internal 10MHz TCXO or external frequency reference
• Jumper-selectable external frequency reference, with signal processing, to suit numerous GPS-locked 10MHz reference sources
• Direct ribbon cable interface to Apollo 15W power amplifier, low pass filters and automatic ATU or Alex Antenna switch, HPF and Tx LPFs
• Low noise, high efficiency, Switching Power Supply designed by Kjell Karson,LA2NI
• Ethernet interface supports fixed, APIP or DHCP IP address
• Hermes responds to ping and ARP requests, auto senses Ethernet cable connection and connection speed

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

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

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 on information regarding Hermes on his web site here http://www.n9vv.com/hamradio.html

(click for larger image) photo courtesy Abhi Arunoday