[ Most recent update: 24 Oct 2011 (Minor changes to text.) ]
TOOLS
If you are going to build stuff, you will, of course, need some tools. Chances are, if you are reading this, you already have most of the tools you need to get started building. If not, the Construction Techniques chapter in the ARRL Handbook does a good job of showing what you need. Actually, the ARRL Handbook is one of the most useful tools you can have, so consider it to be "tool number one" on your list. You can sometimes find used Handbooks, on the “freebie” table at your local Ham Club meeting. I’ve seen them in used bookstores for five to ten bucks. Even if you pay the new price, whatever that is these days, the Handbook is worth every penny.
You don’t need all the items mentioned in the Handbook in order to get started. I think a minimum list should include:
[] ARRL Handbook (tool number ONE)
[] Long Nose Pliers
[] Duck Bill Pliers
[] Diagonal Wire Cutter (commonly called “dikes”)
[] Wire Stripper for removing insulation from wire
[] Assorted Screwdrivers (at least a couple sizes each each: slot and Phillips)
[] Assorted small wrenches, both traditional English and Metric
[] Soldering Iron (25 or 30 Watt “Pencil” type)
[] Quarter-inch Electric Drill and Assorted Drill Bits
[] Hack Saw with Blade(s)
[] Pocket Knife
[] Digital Multimeter (DMM) that measures Voltage, Current, and Resistance. You can get a basic DMM that is more than adequate to do all the measuring required for ten dollars, or less. For less than a hundred dollars, you can get a DMM that includes a transistor and diode checker in addition to measuring Voltage, Current, Resistance, Capacitance, Frequency, and Temperature.
Just about any DMM will serve you well. The DMM I use most, pictured below, is a cheapie that I purchased for $2.99 (plus tax) on "sale" at Harbor Freight a few years ago.
TIP OF THE DAY: Virtually all DMM’s come with a standard pencil-type test probe. The first thing I do with a new DMM is to remove the pencil-type probe tips and replace them with grabber-type probe tips, such as the ones shown here.
Grabber-type probe tips are relatively inexpensive, about $2.50 each, plus shipping, and they are worth every penny (and then some) when testing or troubleshooting. I use grabbers on all my test equipment.
[] 12 volt POWER SUPPLY. Like many things electronic, power supplies come in a variety of sizes and prices. For the project(s) presented here, you will need a power supply that can deliver a nominal 12 volts and current of about 2 amps. Most of the individual modules require only a fraction of an amp for testing and operation - - the Transmitter Amplifier module will require about 2 amps.
While not absolutely necessary, a REGULATED supply with ADJUSTABLE output and METERING for both Voltage and Current is a great help when building and testing circuits, particularly when powering up a circuit for the first time. The front panel of a home-brew supply that meets these requirements is shown below. It fits nicely into an aluminum box that measures about 7 x 6.25 x 4.5 inches.
This supply has two separate outputs: The banana jacks on the right provide regulated voltage that is adjustable from about 1.5 volts to about 15 volts. The banana jacks on the left provide fixed regulated 12.5 volts. The large knob controls the adjustable output.
The meters are connected to the adjustable voltage.
If you already have a 12 volt power source that is not adjustable and/or metered, don't worry about it. I'll show you a way to work around that problem when we get to testing and troubleshooting.
NOTE: When doing circuit testing in general, and for testing newly assembled circuits in particular, always start at near zero volts and s-l-o-w-l-y increase voltage while monitoring the current. This way, if there is excessive current you catch it before your newly built circuit goes up in smoke because of a wiring error.
Yes, I occasionally make wiring errors, and you will, too - unless you are very good and/or very lucky.
Power supplies are easy to obtain. If you don’t already have a suitable power supply, you can purchase one at most any electronic parts outlet. Also, don’t forget to check out your local Ham Radio club when looking for a power supply. With any luck at all, you can pick up a “loaner”, or perhaps even get one of your very own for free.
And, you can, of course, build your own power supply. The ARRL Handbook provides details for building a variety of power supplies.
I recommend the following OPTIONAL TOOLS in addition to the tools listed above.
[] Pistol-grip Soldering "Gun" (100 - 150 Watt). Seldom needed, but when needed, nothing else
will do the job.
[] A GENERAL COVERAGE “SHORT WAVE” RECEIVER, preferably with digital read-out, such as the Grundig "Yacht Boy" pictured below. To be useful for Ham Radio purposes, the receiver must be capable of receiving Single Sideband (SSB) and Morse Code (CW) in addition to the more common AM and FM signals.
In addition to serving as a back-up receiver for your Ham Radio station, a well-calibrated receiver can serve as a frequency meter on your workbench.
If you already have a Ham Radio station for the high frequency (HF) bands, you station can serve as both a frequency meter and signal generator.
[] An electric “hobby” tool with assorted cutters and grinders. The “DREMEL” is one such tool, and there are other brands available.
[] Although an OSCILLOSCOPE is one of the most expensive pieces of test equipment, it is also one of the most useful devices for testing and/or troubleshooting electronic circuits. I purchased a Tektronix 465M 'scope as military surplus several years ago, and it has served me well.
I hasten to add that an oscilloscope is NOT required for testing the circuits shown here, but it would be a great help in case one of the modules you have lovingly assembled just sits there and does nothing. To be useful for testing and troubleshooting Ham radio electronics, an oscilloscope should be rated at 100 MHz, or better. A good, used ‘scope in this category will probably cost somewhere between $500 and $1,000, as of April 2011.
One source for used oscilloscopes is Fair Radio Sales www.fairradio.com/
Don't forget to check out your local Ham radio club where you may find a "loaner".
MISCELLANEOUS SUPPLIES
A list of generic supplies is shown below.
NOTE: While a complete parts list is provided for each module, you might want to buy some parts and supplies in bulk to have materials on hand when needed. For example, to build the complete transceiver you will use:
[] Radio Shack #276-148 Dual Printed Circuit Board, or equivalent. The exact number of circuit boards will depend upon how you package your finished transceiver and what optional features, if any, are included. About a dozen of these boards are required to build the transceiver with no optional features.
[] Electric Tape
[] Shrink-tubing (more expensive than tape, and much better for many applications)
[] Solder (Rosin Core, NOT Acid Core)
[] Insulated copper Hook-Up Wire. #24 or #26 in several colors. White, black, red, green, yellow, orange, and blue are commonly available. I prefer stranded hookup wire, as opposed to solid, because it is more flexible.
[] Enameled solid copper wire, sizes: #28, #26, #24. This will be used for fabricating inductors (coils) as needed. It is helpful to have at least three colors of enameled wire. If, for whatever reason, you want to have only two sizes of enameled wire, I suggest you use #26 and #24.
NOTE: The term "enameled" is used here to refer to the wire commonly referred to as "magnet wire", which traditionally used enamel as an insulation material. Most magnet wire manufactured these days use a polyurethane/polyamide (nylon) insulation material.
[] Bare copper wire, #22. A total of about 12 feet of this is required for the Ground Buss and Tie Points on all the circuit boards used in the transceiver.
[] Two feet, or more (depending upon how, exactly, you choose to package your transceiver) of RG174 1/8 inch diameter coaxial cable.
[] About two square inches of single-sided printed circuit board.
[] About four square inches of thin, solderable sheet metal (preferably copper) for shielding.
[] A #10 nylon or teflon bolt with nut, about 3/4 inch long. Required for mounting the coil that determines the frequency of the variable frequency oscillator (VFO).
NOTE: If you choose to use two or more boxes to house the transceiver, various jacks and connector will be required for the cables between boxes. More about this when we get to final packaging and assembly.
PARTS
A COMPLETE PARTS LIST WILL BE PROVIDED FOR EACH MODULE.
I get many of my PARTS from discarded consumer electronics items and military surplus. I urge you to do the same. First of all, these parts are cheaper than ones you buy from electronic parts suppliers (if you ignore the cost of the labor you invest in salvaging the parts). Second, and probably more important, it is the “green” thing to do. It seems a waste for perfectly good electronic and mechanical parts to end up in the dump along with yard trimmings and kitchen garbage.
Having said that, I hasten to add that it is highly unlikely you will be able to find all the parts you need via salvaging.
If you simply cannot bring yourself to do salvaging, there are numerous suppliers eager to provide parts. The suppliers I use most:
JAMECO www.jameco.com/
MOUSER www.mouser.com/
Digi-Key www.digikey.com/
There are some parts that may be difficult to find via “normal” parts suppliers. These parts, I usually get directly from the company that makes them, or from an authorized distributor:
AMIDON www.amidoncorp.com/
My source for toroidal cores required for some inductors, such as the inductors used in the filters for both the receiver and the transmitter sections of the transceiver.
Mini-Circuits www.minicircuits.com/
For the SBL-1 diode ring mixer used in the Product Detector module.
And, of course, there is always your friendly, neighborhood Radio Shack store, the source for the Radio Shack 276-148 Dual Printed Circuit Board, which serves as the foundation for virtually all the modules used in the transceiver discussed in subsequent parts of this series.
Equivalent circuit boards can be cut from bulk stock at much less cost, if cost is a concern.
If you live in or near a city with a population of 100 thousand, or more, chances are you have an electronic component supplier (other than Radio Shack) within easy driving range. With electronic parts, as with other merchandise, it pays to shop around.
If all else fails, just Google the part of interest, and let Google find a supplier for you.
In Part 3 we will take a look at Packaging in general, and the Radio Shack 276-148 Dual Printed Circuit Board in particular.
- END OF Part 2: TOOLS, SUPPLIES, and PARTS -
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