Difference between revisions of "Multi-Receiver"

Revision as of 07:42, 25 June 2011

Example of the connection points on the mercury board (Click for a larger image)

The openHPSDR receiver can be run in several configurations. Stand-alone, multiple receivers on a single MERCURY (one common antenna), and two or more MERCURY boards plugged into a single ATLAS (this allows two or more antennas). Each of these configurations require different hardware and software support but all have been successfully accomplished using MERCURY boards.

Stand-Alone

The options is supported by all software and all versions of the verilog code.

Current verilog code is Mercury 2.9 and Ozy 1.7

Multiple Receivers on a single Mercury

This options is supported by KISS Konsole on Windows and ghpsdr3 on Linux and (Windows under development).

This option is only supported by the Ozy 1.8 and Mercury 3.0 verilog code.

Multiple Mercury boards

This option is supported by KISS Konsole versions >1.0.6 on Windows and ghpsdr3 on Linux and most recently by a modified test version of PowerSDR v1.19.3.4 on Windows.

Dual Mercury board operations (Windows): Diversity operations using two coherent Mercury receivers is implemented in PowerSDR v1.19.3.4.diversity20 (K5SO 12MAY2011). This program is a modification of PSDR v1.19.3.4 and uses a radar-screen type display to adjust relative gain/phase of the non-reference IQ data stream to achieve diversity operation. Polarization diversity or spatial diversity are possible, depending upon what inputs are provided to the two Mercury boards. Mercury firmware v6.4 or v6.6 should be used with PowerSDR v1.19.3.4.diversity20, these programs are available for download from http://k5so.com/HPSDR_downloads.html.

Triple Mercury board operations (Windows): Directional steering and nulling operations using three coherent Mercury receivers are implemented in PowerSDR v1.19.3.4.directional1 (K5SO 20JUN2011). This program is also a modification of PSDR v1.19.3.4. The program provides a large user display interface that allows the user to select the receive direction and independent phase/gain control of the two non-reference Mercury boards. Mercury firmware v6.4 or v6.6 should be used with PowerSDR v1.19.3.4.directional1; these programs are available for download from http://k5so.com/HPSDR_downloads.html. Using triple coherent Mercury receivers provides up to 4.8 dB of signal gain relative to single Mercury board receiver and with careful phase adjustments can provide up to 70 dB of null on selected signals, depending on band conditions.

Mercury firmware v6.4 and v6.6 are compatible with the current versions of Bill KD5TFD's PowerSDR v1.10.4, KISS Konsole, and PowerSDR v1.19.3.4 therefore it is not necessary to change the FPGA firmware in the Mercury boards when switching among those programs. Power cycling the HPSDR board set (or alternatively, re-running initozy11.bat without power cycling) is all that is necessary to be able to switch between the programs in order to automatically load the proper Ozy/Magister FPGA code. Metis v1.3 also may be used with multiple Mercury boards.

The second and third Mercury board can remain on the Atlas bus while running the other programs with no ill effects; the second and third Mercury board is simply ignored by the other programs.

Required Hardware Configurations To Use Multiple Mercury Boards

Each Mercury board must have jumpers in place to specify an address for the board. Each board will have a different jumper-selected address. The address is specified by placing jumpers on J5 (GPIO pins) on the Mercury board. Looking at the Mercury board with the Atlas bus connector down, the GPIO pins on J5 are arranged such that the lowest pair of pins (closest to F1) are GPIO pins 1,0. Without a jumper, the logic value for the GPIO pin pair is "0", with a jumper across the pins the logic value is "1". The Mercury board address is specified as a 3-bit address according to the jumpers placed on J5. The GPIO pins on J5 are assigned as follows:

GPIO pairs:

9,8 = Mercury ID bit 2,

7,6 = Mercury ID bit 1,

5,4 = Mercury ID bit 0,

3,2 = Channels_8_1 bit

1) When using multiple Mercury boards ALL of the Mercury boards must have GPIO pins 3,2 jumpered. This jumper specifies that the data from the board will be sent to a single, board-specific Atlas bus line that is associated with the address indicated on GPIO pins 9-8, 7-6, and 5-4; as opposed to sending its data to Ozy over eight Atlas bus lines as is the case when there is no jumper across GPIO pins 3-2.

2) The address of the first Mercury board should be "000", selected by having no jumpers on GPIO pins 9-8, 7-6, or 5-4. The address of the second Mercury board should be "001", selected by having a jumper on GPIO pins 5-4; and so on for any additional Mercury boards present.

Therefore, for dual Mercury boards, the 3,2 GPIO jumper pair should be on both Mercury cards, the first Mercury board is set for Merc_ID = 000 (no jumpers on pins 9-8, 7-6, or 5-4) and the 2nd Mercury card is set for Merc_ID = 001 (a jumper across the 5,4 pair).

3) Configuring the 122.88MHz clocks on the Mercury boards:

3a) place a jumper on the CLKSEL "I" pins (lower two pins of the three CLKSEL pins) on one of the Mercury boards (this will be the "master" Mercury board), no such jumper is placed on the equivalent pins of the slave Mercury board,

3b) place a jumper on JP9 (enabling the 122.88MHz oscillator) on the master Mercury board but not on the (other) "slave" Mercury board

3c) place a jumper from the Atlas C16 pin to J8 (Aux Clk input) pin nearest the FPGA on both Mercury boards

3d) connect, with a twisted wire pair, pin 2 of JP1 (CLK SELECT) and a ground connection of the master Mercury board to pin 2 of JP1 (CLK SELECT) and a ground connection of the slave Mercury board, see photos at http://www.k5so.com/Clock%20connections.html.

3e) in PowerSDR, select Setup>Excalibur for the 10 MHz clock source and Mercury as the 122.88 MHz clock source.

Now both Mercury boards will be operating from the single 122.88 MHz oscillator on the master Mercury board. The twisted-wire connection between the Mercury boards is required to achieve long-term coherent operation of the two Mercury boards.

4) 10 MHz clock on Mercury: The 10MHz clock for the Mercury boards should be taken from Excalibur (or whatever external 10MHz source you use) via the Atlas C16 pin, with Mercury jumpered as noted in 3d above.

See also

• Multiple independent receivers - how to set up on Windows - not the same as above, but related.