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SDR on a shoestring

In November I spent $10 on a receiver kit and yesterday finally finished putting it together enough to hear signals on 80 meter CW. It was my introduction to software-defined radio; the kit was a SoftRock Lite, kitted by Tony, KB9YIG.

I had been on the fence about SDR for quite a while, and the bargain-priced SoftRock series tempted me more than once in '06. But the psychological threshold broke when the single-band SR Lite was introduced. Even if I destroyed the parts during assembly, I wouldn't be heartbroken over the loss of $10.

As it turned out, the surface-mount parts weren't all that difficult to deal with. I just used my usual construction gear and techniques and had success. (I am glad an extra capacitor was packed with the kit, since I accidentally disintegrated one with a solder sucker — lesson learned!) Our on-board sound card is adequate for the job, and I simply used a telescoping whip as an antenna for the test.

Once I figured out a simple sound setting in Windows, the free software went to work and W1MK was in my SWL log. At dusk, I heard (and watched) numerous other stations on the 48-kHz band of frequencies (including NEQRPer AI2Q).

SoftRock Lite assembled

That bandwidth is my only disappointment so far. The NEQRP net is 15 kHz above the top end of my SoftRock's coverage! And W1AW is even further afield.

I don't expect to leap with both feet into SDR -- I'd rather do my hamming without a computer in front of me -- but it's very cool to dip a toe into the water. So I'll second N1RX's recommendation: Give these simple, inexpensive kits a try! (A 80/40 RXTX is about to be shipped... got $32 to spare?)

Comments

As Scott says, the SoftRock Receivers (and now the new transceiver) can be a blast. The 80M Softrock uses a LO running at 4X the center frequency of the received bandwidth. The kit ships with a 14.060 MHz crystal standard. This sets a center freq of about 3.51 MHz. If you substitute a common 14.318 crystal off an old computer board, the center freq is now more like 3.57 MHz, and puts the NEQRP net freq and W1AW in tuning range. You did save all those old video boards and such, didn't you? Have Fun!
-Bruce N1RX

Found myself a 14318 xtal, switched the divider from x8 to x4 (the SR Lite comes with a 28 MHz xtal), and am listening again. Next week, W1AW and NEQRP net. Thanks for the hint, Bruce.