Tuesday, November 16, 2010

Building the Small Wonder Labs PSK-20

Encouraged by success in building the Hendricks Scout Regen shortwave receiver last winter, I decided to take the next step -- building a transceiver. I like phone QSOs, but my first love is digital, particularly PSK31. After looking around I settled on Small Wonder Labs' PSK-20 kit, a crystal-controlled QRP SSB rig operating at 14.070 mHz. While not a project for beginners, construction doesn't require advanced tools or calibration equipment. You'll need a multimeter and a 25 watt soldering iron plus the usual assortment of needle nose pliers, diagonal cutters and wire strippers.

The assembly instructions are clear, and the silk screened printed circuit board makes placement of components straightforward. Stage operation throughout construction can be checked with strategically placed tests using a multimeter. Two transformers were missing in the original shipment, but Small Wonder replaced them with no hassle. The only serious challenge was winding the four toroids, but a careful count of the turns reduces the chance of error.

Small Wonder recommends using Digipan to align the transceiver and for subsequent operation. I prefer Ham Radio Deluxe, so after alignment with Digipan I set up for operation with HRD.

With only 3 to 4 watts output, making a QSO requires patience. Not only that, but my vertical multiband antenna is hardly ideal for QRP operation. Nonetheless, my patience was rewarded with a contact -- AJ4YM in South Carolina (470 miles) . In quick succession I racked up contacts with K9AAN (500 miles), NS2C (840 miles), and VE4KZ (1207 miiles). And through PSK Reporter I can see my signal reaching the West coast, about 2400 miles from my QTH in central Pennsylvania.

It took me about a week's worth of evenings to build the PSK-20. Now, every evening -- and a lot of weekends -- are filled with my latest self-imposed challenge. Making a QRP contact with Europe!

-Steve KB3IHX

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