A word on amateur radio kits

Posted by Nate Bargmann on Mon, Dec 17, 2012

Over the next few weeks I plan a series of posts on the amateur radio kits that I am building this winter.  The other night I was describing the first one I am building, the AC-1 Junior by Dwight, KG4HSY, a single tube 40m CW transmitter with a roundtable group on 160m.  I was asked by Mike, K0XYZ, if I thought it would be a good first kit for someone getting started.  After considering it for a bit I offered that I thought it would be a good first kit for someone wanting to explore vacuum tubes but probably not for a very first kit due to the high voltage present.  That conversation gave me the idea for this post

Like most any recommendation for the newcomer, something relatively simple is often a good choice for a fist time project.  As noted in my previous post about the code oscillator, it was my first electronics kit and its construction involved a few different techniques from printed circuit board soldering of through-hole components, to soldering wires to various jacks and a volume control.  The component count and the simplicity of the circuits meant that a newcomer to electronics could probably troubleshoot it with a multi-meter.  Battery power from a 9 Volt battery meant that poking around in the unit posed little hazard.  Taken together, these are probably good qualities of a kit intended for a first-time builder.

As Heathkit is no longer in business and Morse Code is no longer a requirement for licensing, a code practice oscillator is probably not the first project that comes to mind for the would-be builder.  One project worthy of consideration may be the Scout regenerative receiver by Doug Hendricks, KI6DS.  At this time I am awaiting delivery of a Scout kit.  Judging by the assembly manual available on the Web site, it rivals the legendary Heathkit manuals.  Even at that, some aspects of this kit’s assembly may benefit from advice of an experienced builder ( the kit is targeted toward Boy Scouts working toward the radio merit badge where, presumably, someone familiar with electronics kit construction is close at hand) although if the manual is followed exactly, assembly should be completed without issue.  As a regenerative receiver, the kit offers the builder a chance to examine a reasonably simple receiver and have fun monitoring the amateur 80, 60, and 40 meter bands along with broadcast and other shortwave curiosities between 3.5 and 10 MHz.

Besides relatively simple receivers, QRP (lower power, less than 5 Watts) transmitters are also popular in kit form from various vendors.  Perhaps the most popular vendor of amateur radio kits from station accessories to 100 Watt transceivers and a 500 Watt amplifier is Elecraft, a small company in California dedicated solely to its amateur radio product line.  While some of Elecraft’s kits are no-solder final assembly affairs—K3, P3, KPA-500—the rest are of the complete assembly variety.  Elecraft’s manuals are also very good, rivaling the Heathkit manuals of yore, and Elecraft’s customer support is highly rated.   A new kit builder could do much worse than buying an Elecraft kit, in my opinion.

While waiting for that first kit to arrive some tools and supplies are worth procuring.  First a reasonably large work area that is well lit is essential.  A sturdy bench that is comfortable to work at makes kit building a pleasure, not a chore.  A DC power supply with adjustable voltage output and current limiting will serve you well into the future (multiple voltage outlets are another nice feature).  Modern components are quite tiny so good lighting and possibly a magnifying lens are required to properly identify components.  Some kits require static electricity protection so an anti-static mat and wrist strap that are grounded may also be required (Note!  Always use a properly designed and designated anti-static mat/wrist strap. These mats/straps contain a high value resistor to guard against electric shock.  One should never strap their body directly to ground without such protection.).  Basic hand tools such as nut drivers and screwdrivers (straight blade, Torx, and Philips), needle nose pliers ( large and tiny), wire stripper, diagonal cutters, flush cut cutters, and Allen wrenches will be a good start.  An accurate ruler with both inch and metric rules is useful as is an X-acto knife or two and a small flat and round file to clean up slightly misaligned holes.

Among the nice to have but not always necessary tools are a Dremel tool, hot glue gun, emery board/sand paper, circuit board holder, a compressed air source (canned air is fine), freeze spray to identify a thermally sensitive component or solder joint, and even an Internet connected laptop/computer to look up component or other data online.  Extra supplies such as hardware can be built up over time as will a “junk box” of extra parts.

As most electronics kit building requires a soldering iron, it is probably the first tool one thinks of when jumping into kit building.  Most kit soldering can be done with a 25-35 Watt soldering iron with a fine tip.  Larger soldering irons may be useful in special cases but otherwise are too bulky and too hot for delicate work.  Fine wire electronics solder is preferred as larger gauge solder will give a greater chance for solder bridging (an undesired condition where two connections that should be isolated have continuity due to improper soldering techique).  Desoldering braid and or a desoldering pump should be handy in those rare cases when a component needs to be removed.  If life leads you down a path of a lot of soldering, a temperature adjustable soldering station will be a worthwhile investment.

As soldering properly is critical to having a working kit, engage yourself in some soldering practice, particularly if you’ve never done it before.  Soldering tutorials can be found around the Internet.  Study them and then practice on some scrap circuit board first.

Perhaps an even greater art than soldering is desoldering!  I had plenty of practice removing components from scrap TVs I was given in my early years in the hobby.  Desoldering properly is critical for performing electronic repairs.  Careless desoldering can lead to ruined circuit board traces or even other damage in an electronic device.

Kit building in and of itself doesn’t teach much about electronics if all that is done is stuffing the board(s) other than identification of components.  On the other hand, careful assembly and referring to the schematic and circuit description can at least give one a basic understanding of the assembly being performed.  Kit building is no substitute for an understanding of electronics but can certainly be used to enhance such an understanding.  Kit building will allow you to develop good construction skills and may even give you a chance to learn some troubleshooting and repair skills.  Most of all, a successful kit build is rewarding when it works the first time and the kit becomes a useful item in your shack.  Kit building will give you the skill and confidence to take the next step, homebrewing!