WA5BDU - Nick Kennedy's
Ham Radio Page

I've been enjoying the hobby of ham radio since being licensed as WN5BDU in January, 1962 at the age of thirteen.  I've enjoyed many facets of this diverse hobby over the years, but I remain mostly a CW (Morse) operator.  On the air activities include casual QSOs and competitive events such as contesting and a bit of DX chasing.  Off the air, I'm building stuff or writing microprocessor code.

I've lately spent a lot of time involved with a development in ham radio which emphasizes small, simple (usually) low powered radios, called the QRP movement.  QRPers tend to use CW a lot and also like to build equipment from kits or from scratch.  The technical side appeals to me.

My Rig - Current Equipment

Elecraft K3 my main HF rig, KX3 for field. Hallicrafters HT-40 1960s novice tranmitter Drake 2B classic tube receiver with 2BQ Heath VF-1 classic VFO from 50s & 60s K8RA mini paddle KT-34A 4-element triband beam at 48 feet Lots of home built radios

ICOM IC706-IIGX for mobile & VHF W6AAQ screwdriver antenna for HF mobile ATS-3 sophisticated QRP rig in an Altoids tin Begali Pearl keyer paddle 130 ft dipole fed with 450 ohm ladder line Line length switch for above Quarter-wave inverted-L for 160 meters

History: My older radios and times


Technical stuff - my projects

One-chip receiver	A 40 CW meter receiver using the TDA1072 AM radio chip
EFHW Antenna Matchers	The end-fed half-wave antenna is enjoying popularity for portable use due to its ease of erection and no-feedline design Here are two matching circuits for the EFHW
Introduction to LTSpice (pdf) Introduction (Microsoft Word) Tutorial #1 Tutorial #2	LT Spice is a free circuit analysis program.  It's easy to use but there is the usual initial familiarization problem.  The link at the left is a PDF file of  my introtuction and tutorial.  Download from the link below: http://www.linear.com/designtools/software/
Permeability (current) controlled oscillator	A simple circuit from EDN which varies the frequency of an oscillator by passing current through a toroid, changing its permeability by saturation.  The result shows up in the frequency of the oscillator.
Amplifier to boost DDS output	I have an NJQRP DDS and another designed by K6ESE both of which put out a couple milliwatts of RF power.  This circuit boosts that to about 5 watts for use as a QRP transmitter or to allow the DDS to drive a tube-type transmitter.
A 60 meter SSB transmitter	This is a 10 watt SSB transmitter I designed and presented at OzarkCon in Joplin in 2005.
A simple autodyne receiver	An interesting receiver that can lock to the station being received (such as WWV).
Thermostatic fan control for MFJ-4225MV P/S	A circuit to allow the fan in the MFJ-4225MV (or other) power supply to run only when needed, which quiets it down a lot.
Some mods to KD1JV Butterfly source for DDS	Steve Weber made his source code for the Atmel Butterfly demo board available for users to modify.  I added the ability to toggle between the AD9850 and AD9851 versions of the NJQRP DDS boards plus the ability to use a rotary encoder for frequency control.
Crystal characterization and filter design	From a presentation I gave at OzarkCon in Joplin, Missouri in 2008
1-bit sine generation with a PIC MCU	Just for fun, generating a sine wave with an 8-pin PIC
2M FM Receiver with MC3362 chip	I've seen several articles making HF receivers out of FM receiver system ICs.  I thought I'd try one as an FM receiver first.  My first iteration uses the Si570 synthesizer controlled by Arduino as LO
My Ham Blog	Here's my ham blog.  Some enteries repeat stuff on this page but a few are found only on the blog.
Squarer circuit for power measurement	Uses four matched transistors in a translinear circuit
2-tube homebrew QRP TX project	A 6CL6 / 5763 crystal controlled 5-watt transmitter
My 1929 Hartley Transmitter	Notes & schematic on my '29 design 2 watt transmitter
PHSNA Article in QQ Sprint 2014	Article on Poor Ham's Scalar Network Analyzer Uses an Arduino and an AD8307 log power measurement IC PDF 2.8 MB
Ladder.ZIP ladder.txt	An Excel spreadsheet that does ladder network analysis including crystal filters, and plots the response. Based on a description by Wes Hayward in Introduction to RF Design.
Phasing RX Powerpoint	I discussed the design and construction of a phasing type receiver at OzarkCon 2016. My powerpoint slide show is linked at the left.

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