Amateur radio is practical: we use what we buy or build. A device can be ugly, deficient, cheap, less than state-of-the-art and still be immensely useful. If it helps you to put a signal on the air you will be successful. There are no asterisks on an operating award because your home brew QRP transmitter was a oddball collection of parts spread across the operating desk, held together with bits of tape and clip leads.
I use computer design tools and breadboards to test my designs. They often remain prototypes for a very long time. Witness my long running project to design and build a digital controller for my prop pitch motor rotators. The breadboard direction indicators sitting on the old 24 VDC power supply and a standalone panel meter is still there and working! Ugly and embarrassing but it gets the job done.
The new one is getting better although not yet completed. With the weather warming it will take a while longer as my focus turns to antenna and tower jobs. That's okay. I don't need a pretty station to be competitive in contests and the DX pile ups.
Despite all the design and prototyping I continue to make many mistakes. Maybe I discover that a design is deficient and I have to research and try alternatives. Or the design is fundamentally sound but impractical when implementation is attempted. Worse, the design and implementation work, it goes up high on a tower and then fails because it isn't immune to abuse by the weather or the flow of high power.
I have not been shy about highlighting my mistakes on the blog. And there have been many! I believe my biggest mistake was to attempt to make a hardware-based antenna switching system. At the time I believed that this would be a relatively straight-forward first step toward a software solution. I was very very wrong! It was mechanically and electrically complex, inflexible, overly large and difficult to use.
I recognized my mistake and (reluctantly) discarded it. However, my first software solution was also deficient. I am still using it but it is due for a redesign. The UI (user interface) is confusing to guest operators and even to me at times. I know because I keep pressing the wrong buttons for the wrong radio or antenna. The next version will be much better, I hope.
There is no shame in making mistakes. That's how we learn. What is shameful is hiding mistakes or denying them and continuing on as if all is well. No one will be fooled by your evasion. Laugh at yourself, accept the lesson and try again -- to err is human.
Other examples of mistakes I've made, and the lessons learned, can be found in the blog. A few examples are gamma matches, 160 meters on the 80 meter vertical yagi, blazing the wrong trail for a Beverage antenna, breakage of scrounged aluminum, and even the choice of manually-tuned tube amps in a station intended to be used by guest operators. Searching my blog for the word "mistake" tags a lot of articles! Many of them are for operating mistakes or small things like forgetting to tighten bolts, but in this article I'll focus on design and construction.
I will also overlook ugly construction. When the ugliness is 100' up the tower, no one will notice but me. When it's on or under the operating desk, I can always cover it. No one dares ask what's underneath the cloth -- most hams have one or more ugly contraptions in their stations.
You've certainly heard this phrase. It means to delay or avoid doing something because there are uncertainties or alternatives. Deciding what is best, let alone perfect, can be fruitless since there may not be one. This is especially fraught when the requirements are skimpy or vague, as they often are for projects hams are wont to build. That is, we really aren't certain what we are trying to achieve. That may be okay in some cases since exploration can be a good way to learn.
The key is to think through the options and research alternatives as well as you are able, then do something. You may choose a poor or non-optimum path, but so what? We aren't building rockets or nuclear reactors where failure isn't an option. When an unforeseen difficulty arises, correct your course or throw it away and try a different approach. Don't stubbornly persist with your first choice, or abandon the project because you are consumed by doubts.
That said, I strongly advise against jumping into construction with no analysis at all. Many hams work that way, and I did as well when I was much younger. Impatience can be a curse, leading you into the wilderness without a compass. You may find yourself taking two steps backward for every step forward.
Do at least some planning and design work before jumping into construction, which is usually the fun part. Know your destination and keep aiming at it no matter the bends in the road along the way.
Devil in the details: "minute details can have a big, often negative, impact"
Often the reason we get caught in analysis paralysis is that there can be so many options and details in a project. This is as true for an electronic project utilizing software or PCBs with dozens of components, as it is for towers and antennas where questions about static and dynamic loads, tensile strength and other challenging questions are critical for durability and safety.
Don't be afraid to ask for help. But for many in-the-shack projects you can work it out without serious risk other than a little money and your time. However, don't simply proceed by trial and error since there are fantastic and free design tools for you to use, and online fora where you can ask questions. Those can help you to avoid many elementary mistakes. Examples of design tools include EZNEC, LTspice, KiCad, Elsie and so many more.
That said, a custom design can entail many pesky details that you will have to work through. The shape or position of one part can impact the success of the project. Let me illuminate this with a project that I am currently working on: a 40 meter reversible Moxon antenna. Let's look at the element switching system component where a relay changes each element to be either the driven element or a director. Both elements have the same component but with the roles reversed.
The linked article contains the switching system design which you may want to review before continuing. The only item from that article I'm reproducing here is the element switching schematic. The central coax switch for selecting the driven element is not included in this discussion. That's for the wire version, while the NEC5 design for the rotatable version I'm building can be found here. Full antenna detail will be published after the antenna is up and working.
On the right is the centre feed point of one of the elements, as it has been assembled in the hay field. On the left are most of the parts for the switching system that will be placed at the feed point. There are a DPDT relay, non-conductive spacers (to support the reflector coil and element connector tangs), solder lugs, custom made aluminum tangs to connect the switching system to the element halves, an ABS enclosure and a coax connector. Here are some of the details I've been considering in the design:
- Minimum enclosure size to accommodate the parts that permits good RF design and that minimizes wind load. It must be strong enough to withstand the weather.
- Minimize lead lengths to the connector, coil and element for low stray inductance.
- Fits over the element hardware and can be secured, while allowing ease of attachment and maintenance. Those tangs will be formed to fit under the hose clamps.
Consider a few of the many details that I must address:
- A high-Q coil tends to have equal diameter and length with space between the turns. For the required 1.2 μH coil those dimensions are on the order of 3 to 4 cm. The fit is tight so I've made the length a little longer than the diameter.
- To adjust the coil (mainly due to lead inductance), one tail must be solid (for support) and one flexible. That is, to compress or expand the coil.
- If the support spacers are too close the aluminum tangs must be positioned outboard of the screws, and inboard if the supports are wide apart. I need them close so that they can be bent outward to fit under the hose clamps (projecting outward from element centre). That increases the risk they could touch, but will reduce stray inductance. Also, the tangs must be appropriately sized (width and length) so that the entire enclosure can be rotated in and out of the hose clamps for insertion and removal.
- Will the enclosure stand on the tangs or be tight against the hose clamps or the large element u-bolts? For the former, the risk is that wind load will fatigue cycle the aluminum tangs and ABS enclosure. For the latter, the risk is that weather and the pressure of the clamps on the enclosure bottom could deform the plastic which might eventually crack.
- Stiff wire must be used for internal wiring so that the relay is held in place by the wires. This is the dead bug style I used in similar cases such as auxiliary coax switches and stack switches. Since #18 solid copper wire has worked in the past I'll use it in this project.
There are other details which I've omitted; there are a lot of them! Perfection is impossible but analysis is still prudent. Yet I will confidently predict that there will be one or more mistakes made in my design and construction choices.
One mistake already discovered is that the plastic spacers (threaded for #6 screws) won't hold the screws very well when adjusting and torquing the top and bottom screws. Therefore I will place nuts on the bottom screws (for the tangs and solder lugs) to hold them securely. The coil solder lugs on top don't have to grip the spacer as solidly. The screws will have to be cut to measured lengths so that they grip well but don't get close enough to arc or short inside the spacer.
At this point readers may wonder why I'm going into this excruciating amount of detail. But that's just it: the devil is in the details. Even a simple project entails a large number of decisions about details that will have consequences. Those choices are inter-dependent since they affect each other.
All of us must make many choices, consciously or not, when designing and building any project. When a problem is inevitably encountered, we revise and improve. Mistakes are just part of the process.
There is no escaping the details. Buying a product instead of home brewing also entails details in its installation and use: there are interconnection and system details to be worked out. A station like mine is very complex and it can be a struggle to make everything work in harmony.
Accept that mistakes will happen
Saying that mistakes happen is unsurprising and uninformative. What I tried to communicate in this article is to accept their inevitable appearance no matter how cleverly we design and build the contraptions we use in our stations.
But it is important that we learn from our mistakes; that's one of the wonders about our technical hobby -- that there is so much to learn. Learning can be fun and fulfilling even though we may cringe when a mistake is discovered dangling from a tower or by the acrid smell of burnt electronics.
We should do our due diligence, while being careful not to obsess over preventing every possible point of failure. There lies paralysis, and that's never good. Move forward by trying something when you're stuck, or get a second opinion from someone with greater experience.
The only time to stop is if a mistake would risk life or property. That's one time that you are advised to seek an expert. Asking for help is not a sign of weakness. Nor is admitting and correcting a mistake.