Building Your First Transceiver Kit
--Ten Tips for the First Time Builder--
by Robert S. Capon, W3DX Return to Home Page
(Formerly WA3ULH)
©1996-97 Robert Capon, All Rights Reserved
Have you ever though about building your very own transceiver kit? I had wanted to build a full functioning transceiver ever since I launched my amateur radio career 24 years ago.
When I attempted my first kit I had a false start with a project that was far beyond my ability. Its documentation was poor, the printed circuit board was not silk-screened for parts placement, the component density on the board was very high, and the wiring was extremely complex. I never completed the kit, and it was actually several years later before I made my second attempt to build a kit.
What I did not realize is that one of the most important aspects of building your first transceiver kit is selecting a kit that is appropriate for your skill level.
The good news is that even though Heathkit is no longer in the amateur radio business, there are still a number of firms offering very good ham radio kits that are suited to all skill levels from beginner to expert builder.
This article is designed to suggest criteria for selecting your first kit, and provides ten tips to help you successfully complete the project. So take the plunge, and discover how rewarding it is to build and operate a radio that you’ve made yourself.
Before you start, take a moment to observe several safety precautions. Be sure to work with safety glasses, which will protect your eyes from splatter of hot solder and from flying leads and debris. Also, be especially careful with the soldering iron, and remember to locate the iron where no one is likely to trip over the electrical cord. Keep your soldering station away from small children and pets, and be sure to unplug the station after each session.
Tip 1: Select The Right Kit
Transceiver kits come in all shapes and sizes, and it can be hard to select the right kit from among the choices available. Single band kits are much simpler to build and have a lower parts count than multi-band rigs. Choose a kit with a silk-screened printed circuit board to facilitate parts placement, and with a silk-screened and punched enclosure so that you don't have to do any metal work on your first kit.
For your first kit, select a kit that keeps point to point wiring to a minimum, or one that uses on board connectors or a wiring harness to facilitate construction.
CW kits are somewhat easier to align than sideband kits, so most first time kit builders start with cw rigs before graduating to more advanced projects. Be sure to choose a kit that has plenty of room inside to work. Finally, choose a kit that is well documented and is well supported.
Wilderness Radio makes two kits that are ideal for the first time builder, the "Super Simple Transceiver" and the "Norcal 40B". Both are superhet cw transceivers that come with silk-screened circuit boards, punched encosures and superb documentation. The kits have a novel design in which components mount directly to the printed circuit board, so there is no point to point wiring.
Tip 2: Read the Documentation Before You Start
Before you begin, read through the documentation very carefully, paying special attention to the information provided on component value data. Kit suppliers do a good job of anticipating your questions, so an ounce of prevention by reading the documentation is definitely worth a pound of cure.
Tip 3: Sort the Parts
If this is your first kit, take some time to prepare before building the kit. Before you open your first parts package, you may want to purchase a plastic compartmentalized parts box, which can be very handy for sorting components. I found some very suitable boxes at a local housewares/ kitchen supply store.
With every kit that I have built, there is at least one or two components whose markings are hard to figure out. However, what seems complex when you first open the kit can be simplified by sorting out the parts, and checking off the items on the parts list supplied with the kit. When you've checked off all of the clearly marked items, you'll probably be left with only one or two confusing components, and it will be much easier to figure out which is which.
Tip 4: Work With the Right Soldering Equipment
Most of the troubleshooting problems that are encountered by both experienced and inexperienced builders alike boil down to soldering defects. If you do not already own a soldering iron, I recommend a low wattage iron, (such as the Radio Shack #64-2067, a 30 watt pencil), with an extra fine pointed tip. This will be plenty of heat for printed circuit work.
I also recommend the purchase of a good soldering iron stand (such as the Radio Shack #64-2078) with a sponge tray. Using a good stand is an important safety consideration, and keeping the iron clean is one of the tricks to successful soldering. After every few solder joints, wipe the hot iron across the wet sponge to keep the tip clean.
Finally, you will probably need a good de-soldering pencil (such as the Radio Shack #64-2098A). I have never completed a kit without soldering at least one component in the wrong place. The de-soldering pencil will enable you to remove components with minimum wear and tear on the printed circuit board.
Tip 5: Put the Parts in the Right Place
One of the most common problems encountered when troubleshooting kits is that parts have been installed in the wrong place. I use a technique to help prevent this from happening. I populate the board with each category of component before I solder. For example, I install all of the resistors, solder them all at once, then clip the leads.
If you follow this technique, it becomes much harder to make a parts placement mistake. For example, if you install a 2N4304 transistor in the hole for the 2N4306, you'll catch your mistake when you get ready to install the 2N4306 and can't find it.
If you use this technique, you will be populating the printed circuit board with a lot of parts at once. One technique to hold the parts in place as you turn the board over to work is to bend the leads out at a 45-degree angle.
Tip 6: Put the Parts in the Right Way
Some parts have a precise polarity in which they must be installed, while other parts can be installed either way. Here is a rundown on parts polarity:
Tip 7: Wind and Prepare the Toroids Properly
Double check your toroid windings against the instructions supplied with the documentation. Remember that you count toroid turns on the inside of the toroid. Theoretically, the magnet wire supplied with most kits to wind the toroids uses a coating which is melted off during soldering. I have found, however, that the coating does not melt off easily, and that the resulting solder joint does not make a good connection in all circumstances. It is safer to carefully scrape away the coating with an X-acto blade or with sandpaper and tin the leads prior to soldering.
Tip 8: Keep Lead Lenghts Short
Make sure that component lead lengths and wires are as short as possible. This reduces the opportunity for accidental short circuits, and helps to eliminate problems related to stray RF in the transceiver.
Tip 9: Take Care with Wiring
When I built my first radio, one of my two mistakes was a wiring mistake with the receiver's VFO. (I reversed the VFO signal and ground.) Carefully check through all of your wiring to look for errors in routing wires. After you complete the wiring, put the kit away for a day, and come back and check each wire step by step with the instructions. It's a good idea to do this before you power up the radio for the first time.
Tip 10: Review Before the Smoke Test
Before you apply power to your rig during alignment, double check all of the wiring, especially the wiring to the power jack. When you check your power connections, check both the connections within the radio and double check the power cord to your power supply or battery. Most radios will be damaged if you reverse the positive and negative leads to your power source. Before you apply power, check the resistance between the center conductor and ground of the radio power jack. If the resistance is close to zero ohms, you probably have a short circuit. Be sure to find the wiring problem or solder defect before you apply power. If the documentation provides other pre-power checks, be sure to follow them before you apply power!
Armed with these ten tips, you're ready tackle your first transceiver kit. When you complete your project, you'll discover the satisfaction of building your own radio, and making contacts with a homebrew rig.
After you’ve mastered your first kit, you can begin to move on to more difficult challenges. There are dozens of great kits to chose from among today’s kit suppliers. These kits include cw transceivers, single sideband transceivers, 2 meter FM transceivers, 6 meter transverters, memory keyers, antenna tuners, watt meters, digital displays and even linear amplifiers! So take the plunge, and discover the joy of kit building.