[hpsdr] Photos of SDR-1000, HPSDR, & LP Filters Enclosure Project

[Guy Atkins]

HPSDR enthusiasts may be interested in four photos I've posted to the Web:

http://www.guyatkins.com/files/sdr_front.jpg Front of homebrew
SDR-1000/HPSDR (receive-only) enclosure with Griffin Powermate tuning knob
and LW, MW1, MW2, and Bypass filter position switch. 

http://www.guyatkins.com/files/sdr_rear.jpg Rear view with USB ports for
Griffin Powermate tuning knob and PC control line, antenna input BNC, audio
in/out jacks, and cooling fan. 

http://www.guyatkins.com/files/sdr_inside.jpg Inside view, showing original
SDR-1000 board stack along side of HPSDR "Ozy" control board and "Janus"
sound card replacement board; W1VLF custom low pass filters for LW, MW1, MW2
with shielded rotary switch; cooling fan; custom, balanced I/Q connection
between SDR-1000 and Janus board; various other custom cables, including
short DB25-to-DB25 IDC ribbon cable (replaces bulky parallel port cabling).
Torroid and binocular core ferrites used throughout for RFI supression. 

http://www.guyatkins.com/files/sdr_inside2.jpg Another inside view of the
homebrew SDR-1000/HPSDR receiver enclosure. 

I've recently completed the combining of my receive-only SDR-1000, HPSDR
Janus and Ozy boards, and Paul Cianciolo W1VLF's low pass filter modules
into a single enclosure. This effort does away with three separate
assemblies and a snarl of external cabling, and makes the whole affair more
compact and neater.

I was going to need to build an enclosure for the HPSDR boards anyway, so I
decided to repackage the entire SDR radio's components under "one roof." A
Griffin Powermate USB knob is attached to the cabinet front for
"traditional" knob tuning to complement keyboard/mouse control. The low pass
filtering for longwave, medium wave lowband, medium wave highband, and a
bypass position is accomplished by a four-position rotary switch to the left
of the tuning knob.

I avoided having to use a separate power supply for the HPSDR boards' +12V,
-12V, and +5V requirements by supplying appropriate voltages directly from
the SDR-1000 board stack. The -12VDC regulator on the HPSDR Janus board
conveniently uses the -15V output from the SDR-1000's DC-DC converter as its
input supply. I previously modded the DC-DC converter by replacing the stock
chip with a much higher quality, low-RFI module bought on Ebay. (No more
wandering spurs!)

The SDR board stack conveniently sits on some unused Atlas board DIN
connectors, and four spacers on the stack are insulated from the bottom of
the Janus board. The stack is secured to Atlas with multiple loops of
monofilament fishing line, around the stack spacers and tied through
plated-thru holes in Atlas. A thin 1/8" sheet of medium-density foam fits
between the upper Ten-Tec enclosure cover and the edges of all boards except
Atlas. The slight pressure with this foam completes the securing of the
boards and makes the assembly quite stable.

One of the DIN connectors is still available for the future Mercury board,
although I will have to move the project to a larger enclosure if I want to
make more slots accessible for other HPSDR boards/devices.

Lettering on the enclosure (a Ten-Tec BK-959) is still to come, but for now
it's a fully functional SDR-1000 with improved dynamic range and lowered
noise floor due to the HPSDR boards replacing the former Presonus Firebox
sound card. I have yet to do any serious DXing with the radio connected to
the HPSDR boards, since I hadn't used them until this project was completed.
However, I'm heading north to the Queen Charlotte Islands (BC) today for a
week-long DXpedition with other MW enthusiasts...the setup will get a
thorough test soon!

More details and photos on the low pass filters I use for trans-Pacific MW
DXing with the SDR-1000 can be found here: www.sdr-1000.blogspot.com

Guy Atkins KE7MAV
Puyallup, WA