Category Archives: Projects

Work-around for Pesky OS X Kernel Panic with Arduino

I’ve been bouncing between my Windows PC and a Macbook Pro as I am writing the code for the Feather NTP Clock.  (Gotta love BitBucket and TortoiseHG which provide me with the latest source code wherever I am). While it … Continue reading

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Feather NTP Clock

While my obsession with accurate time continues, these days my obsession with avoiding the hassle of resetting clocks on DST/STD changeover and power failures grows. My original NTP Clock, based on the Raspberry Pi worked just fine, but it really … Continue reading

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Using a Diplexer (Duplexer) as a 2-meter LPF

First off, to be clear, I’m talking about a Diplexer, the small device that will fit in your pocket and costs < $60, that is used to combine 2-meter and 70-cm rigs to use a single antenna feed-line. However both … Continue reading

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KA1QYP Half Pint QRP Transceiver Passes FCC

In our continuing quest to evaluate the output purity of various QRP kits, Willy W1LY constructed a Bill KA1QYP Half Pint Kit. The assembled kit produced a solid 600 mW output and was one of the cleanest radios we’ve seen.  The … Continue reading

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Pixie with 5-pole Axial Filter Passes

Willy, W1LY, decided to try using the standard unshielded 1 uH axial inductor that the Pixie uses for it’s current 3-pole filter (C5=47o pf, L2=1 uH, C6=470 pF) as the starting point for a 5-pole filter that could easily fit … Continue reading

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Elsie Plot of QRP-Labs 7-pole 40-m LPF

This is the schematic of the 7-pole LPF used in the QRP Labs 40-meter LPF: The plot from Elsie 2.77 for the above filter looks like this: The actual SA response curve looks like this: The curves are remarkably similar. … Continue reading

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A “Better” QRP Transceiver?

NCRC had several reasons for building the Pixie as a club project, and getting it on the air is probably at the bottom of the list.  Fixing flaws in the Pixie design provides learning opportunities.  But by the time you … Continue reading

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Pixie Perfection

As has been noted in several posts, the stock Pixie 3-pole filter is hopelessly inadequate to suppress harmonics.  A typical Pixie will have a 2nd Harmonic that is only about -21 dB down from the carrier.  An external 5-pole filter … Continue reading

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P2N2222A for the Pixie

On Semiconductor has a variant of the old 2N2222A in a plastic case called the P2N2222A and characterizes it as a small signal RF amplifier.  I picked up a few samples and ran three of them through the Pixie.  In … Continue reading

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7-Pole Filter + Pixie

A friend of mine, Paul K1YBE, gave me a QRP Labs 40-meter Low Pass Filter Kit.  The kit came with three T37-6 cores, some #28 wire, 4 caps, a tiny PCB, and a couple of headers. Normally used with one … Continue reading

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