By Matt Erickson KK5DR
Introduction
In the beginning, all ham radios were home brew. Over the last century, ham radios have become mostly commercially built.
A few of us have returned to the roots of radio, and build at least some of our gear. You may only make antennas you may build tuners, amps, or even your own radios. Its all up to the individual as to what you are willing to take on as a project.
I build HF amps, and antenna tuners & antennas. The most complicated are by far the amps. I write this article to try to help the new home brewer get more into and out of their projects.
The reasons you build your own gear may be many or few, public, or very personal. My reasons are both public and private.
Perhaps the most important, and difficult of all, is where to start, and how. My advice is, decide what you want to build, then READ, read all you can on the topic, and find books, and articles that deal with the idea you want. I find that magazine articles are a great source for ideas, procedures, and advice on your project. I read books on radio, and seek the advice of old-timers that have a great amount of experience to draw on. Don’t be afraid to ask questions, and question conventional thinking too. Read as much as you can on related subjects also.
Start small; don’t try to build something that is far beyond your abilities as a beginner. Try a project that is very simple, but will sharpen your skills, and build your confidence. Starting small will mean that you spend less money too. If your project does not finish the way you wanted it to, you will not be out a large amount of money or time this way.
I have had a few home brew projects that didn’t end up like I would have liked, from these I learned where I went wrong, and how not to make the same mistakes again.
This is where most home brew projects go bad, when the builder tries to do the building to fast. Slow down, take your time, leave the finishing schedule, open ended. Take frequent breaks from the project, don't try to start and finish the item in a single sitting. Doing the building to fast will cause mistakes to be made, and in haste will be over looked, and in some cases can cause serious problems later, also you will be unhappy with the end results of a hasty built project.
Think about it
Here is where the project will actually take shape, and can be redone and infinite number of times. The project can be operationally tested, using the known theories in real time or in slow motion, all in the virtual space of your mind's eye. I spend a huge amount to time thinking about my current project, building it, and rebuilding it over and over. I test and retest the operation repeatedly, using what I know about the items theory of operation.
Drawings, sketches, and schematics help the thought process, and hone the operational parameters. It is like 3D virtual modeling that requires little or no effort and can be done anywhere, at any time.
It is best not to think about the entire project all at once, better to pick a specific area, and think it over thoroughly, working out the "kinks", then document what you have on paper, or computer, and study it, to see if there are any errors that you didn't see in your mind, but now show clearly on paper.
Thinking a project through, will make it go much more smoothly.
While you are thinking about your project, come up with a step-by-step procedure for the actual building. Understanding what needs to be done, and when is most important. For example, if you fail to take into account a certain item needing to be done first, and work past it, it might make that item difficult if not nearly impossible to do, when you do get to it.
Thinking about how one step will affect another, and yet another, will go a long way to a smooth procedure.
Think about how you want the item to operate, and how you want it to look when finished. Time spent here will be well worth it in the end.
OOPS!
Mistakes WILL be made. No matter how much you try, they WILL be made, don't get mad, don't get discouraged, just step back, look at what was done, learn from it, and move on.
Most mistakes will be minor, but there can be major flaws too, what is most important, is that you learn how and where the mistakes were made, and how to avoid them again.
Don't be afraid to "try, try again". You will not be defeated, unless you "give up".
Design
Try to use tried and proven designs in the beginning. When you have more experience and confidence you can start designing your own. However, you need to test your ideas, and document them for later use. When testing your designs, build it on a bread-board, and run the tests, if the circuit you have designed works well in the bread-board phase, move on to placing it in a cabinet, and test it again if possible. The results may differ and changes might need to be made.
Books and magazine articles are a treasure trove for designs. Start by coping the designs of others, then add your own personal touches, and variations on the same theme.
Parts is parts
Where to find parts? That is a good question. I have found ham fests to have many parts I can use, and very low prices. In the last few years, I have found the Internet to be a good source for radio parts, but prices can vary wildly, and buying parts site-unseen, can be risky. When buying part via the Internet, you might do well to ask for pictures, from several angles, and physical dimensions, manufacturers name, model numbers etc. Using this info, you can plan their use.
Fair prices? You may ask around, and look at historical sales for a price benchmark. Most of the time the price you pay, is going to be what you are willing to give for the item. Some times if you lucky, you will get a really fair deal, or even a super bargain, and from time to time, you might even find parts for free.
Taking time to search out parts is the key to getting a good value, if you are in a real big hurry, you will likely pay a much higher price. I have spent much more time sourcing parts; than I ever did actually building the project.
Patience is the virtue here.
Safety!
When building a piece of ham gear that has high voltages or RF voltages, safety must be a concern. While designing and building the unit, you will need to be aware that if it is possible to come into contact with lethal voltages during normal operations, the gear is NOT safe. For example, I have seen a few home brew HF amps that had lethal voltage wires exposed on the exterior of the unit, this is NOT good design engineering. If it is possible to contact the wires, even accidentally on the outside of the unit, the item is UNSAFE. On units that have these voltages, it is wise to build in a means of disabling the voltages, should the operator expose the interior of the unit, such as a safety interlock switch.
In these days of personal injury lawyers suing all manner of companies and persons, you would do well to install a safety interlock, should the unit be sold or end up in an estate sale. Should an "idiot" kill themselves on the unit, a civil suite might come your way, or fall on your estate, if the unit does not have any safety devices installed. If you have installed one or more, at least you will have shown that you made a reasonable effort to prevent "accidents".
Cost?
How much to spend? It is nearly impossible to factor into the total cost of a given project, the labor time spent, it has little or no selling value. However, parts have a known value, and can be factored into the cost of the project. How much should you spend? My rule of thumb, is to not pay more than 50% of the price of a commercially built unit, in parts. I try to pay only 30-50% of new cost on each used part, unless the part is new, or must be custom made or ordered.
Being a good "scrounger" is the key to keeping the costs of parts low.
Most home brewers do not build to sell for a profit these days, they build as a matter of pride, and the quest for expanded knowledge, to better understand how radio gear works.
There is no way to explain to a "non-builder", the sense or satisfaction, and pride that you get when a project is finished and works as well or better than it was planned to do.
If the finished project looks as good as it works, is just icing on the cake. The knowledge you gain during the building, will only enhance your ham radio experience.
73 de Matt KK5DR
Copyright © 2005 Matt Erickson KK5DR, All rights reserved.