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N3JIM's 30m software-defined radio

Last updated Sun, 05 Jun 2011

(work in progress)

Back in April 2010 I bought a SoftRock SDR kit for the 30-meter band from Tony Parks, KB9YIG. It sat on my workbench for about a year before I pulled up the build instructions. First problem I encountered: the BOM doesn't match my older kit on one part -- BOM specifies 390 pF caps, whereas I received 220 pF caps. A close look at the schematic showed that 220 pF are actually correct. So time to start building! (June 4, 15:00)

Clean the board with a green scouring pad. Also clean leads of each part, and don't forget to flux before soldering!

Power supply

The first thing to tackle is the on-board power supply. I ran into a bit of a snag here with the voltage regulator. The traces on the PCB are very close together, and I ended up bridging two of them. But solder wick and some creative swearing soon had the problem fixed. ;)

Test results for this section:

Current (with 1kΩ resistor)=4.04 mA

Current (without resistor)=4.34 mA

Voltage at D1 cathode=12.52 V

Voltage at R11=4.93 V

Local oscillator

Nearly half of the components in the kit are for the local oscillator (LO)!

Is this homebrew? I don't think so, since it's a kit. The only thing homebrewed is the enclosure and external connections.