Practical tips for home brewing.

Elsewhere on eHam I recently complained about the lack of technical articles. Hams cannot live on jokes alone.... But this immediately induced a guilty feeling as I realised I had done nothing about it but whine....

I am afraid I cannot offer you great wisdom or the project to build that will end all projects. You might even wonder about the language used in this article as English is not my native tongue. (I was born in PA country). But I think I have something to offer from long experience in home-brewing that might benefit newer hams that feel uncomfortable when they just plug in and play. Because in my very humble opinion a threat to ham radio , far greater than the CW issue, is the lack of interest in THE EXPERIMENT. By the way.... I do not have some sort of master's degree in electronics but was trained as lawyer and have been managing an insurance company for most of my life...

There are many occasions where a modern ham can benefit from some do it yourself. First, you save heaps of money. But even more importantly: making a QSO from a set up that - even as a minor part - contains something that you constructed yourself gives enormous satisfaction. Because when you know how the thing works that you made, you have the power over it and can change parameters and try to do even better! All the knobs and dials on your FTxxx or ICyyy only allow you so much and not more. But when you make something yourself you know you can change that resistor or capacitor and may be get more output, better signal to noise ratio or a higher gain.

Figure 1 - My shack

What do you need for this sort side of hamming... A really big junk box. A box, set of small containers, drawers, baskets and what have you with all sorts of components, bits and pieces, bolts, nuts, brackets and other unthinkables and unmentionables. Never throw away today what you might need tomorrow..... All circuit boards of old, obsolete or discarded equipment have something on them what you might need for your next experiment. I have not less then three shelves with containers in my shed with old boards, parts and equipment; some tens of years old. The other day I used a variable capacitor from one of the boxes of which I remembered that I it bought in a flea market some 40 years ago.....

Printed circuit boards can be easily stripped of components with one of these hot air guns to strip paint. Heat the solder side and knock the board to make the parts fall out. Amazing how many TLL and CMOS IC's survive this sort of abuse. Capacitors and resistors have short leads but are ideally sized for bread boarding or re-use on perf-board. Scavenging single components from a board usually requires desoldering litze of which I always have ample stock.

By the way: do the stripping outdoors.... The XYL (or OM to be Politically Correct) will object because of the smell and it is also healthier in the open air....

I also fill my junk box by selective buying at ham fairs and flee markets and (after dark) picking up the odd TV set, old computer or micro wave from the road side.... Res derelicta, the lawyers call that stuff.

You also need a breadboard and a versatile power supply. The power supply should have minimal 5 V, +12V and -12V at 1 - 3 Amp. So any old computer power supply will do. Decorate it with a voltmeter and/or mAmp meter. But without that it works just as well. I use a couple of old and cheap multimeters that I collected through the years. Lacking that... some component sellers have them for $10 - 15.... I have one of these older Heathkit breadboards cum power supply with built in sine and square wave generator up to 10 KHz. When you find one somewhere.... Buy immediately!

Figure 2- My breadboard

Other handy tools are a simple frequency counter (at least to 50 MC) and a signal generator (available in most flee markets). I also made a couple of marker generators from old crystals and Cmos dividers for various -exact - frequencies, like 1000 Hz, 1 MHz and so on. And of course a good - temperature controlled - soldering iron, various pliers and cutters and a set of screwdrivers and a bit set for taking things apart (and putting them together again - occasionally). Especially the tools make great presents for your birthday, Fathers/Mothers Day and Christmas. Things the XYL (or OM) or the kids can actually buy themselves and in secret without too much instructions and prompting from you.

The breadboard is handy to set up experiments with designs you may find in magazines or on the Internet. Before ordering the PC board just check out if it will work for you and do some experimenting and make some measurements. Sometimes the praised design is not so ideal after all....Use the stuff from your junk box and check out if you really need to buy that kit on offer or that you may have all the - slightly different - components in your junk box already. That makes it really interesting because it might even work better with the components you got.

Experimenting and copying designs for kits with components you already have, saves money and will eventually enable you to buy an oscilloscope instead of another ready made piece of simply reproducible electronics that other people market for profit. This is a really handy piece of gear, for signal tracing, fault finding, aligning and all other little jobs during an experiment. Dual trace, 20 MHz is affordable these days and will do unless you really go SHF...

After the breadboard testing I make most of my designs on Vero-board or - preferably - perf board with little copper islands and not with strips. Connections between components and IC sockets I make with wire wrap wire. Not wire wrapping but soldering. To strip the insulation of wire wrap wire use pliers and knick the end of the wire. The insulation will split and can be cut away with nail clippers. The result looks a bit like needlepoint and it needs the same sort of magnifying glass to do it neatly.

Figure 3 - like needlepoint - you need a magnifier...

Also try to build a library of books and data sheets for the most frequently used components. I have two very thumbed data books, one on semiconductors and one on TTL IC's. The last ten years I built a large favourites list of web sites with data and data sheets. For all the more specialised components in my collection I have the .PDF file with the data sheet and application notes stored in a special directory. Of course there should be an ARRL Handbook in every shack and a subscription to an electronics experimenters magazine keeps you up to date with developments.

When experimenting make copious notes of what you do, what changes you make and what the results of these changes are. This helps to find where you went wrong or why the circuit became smelly and started to smoke. That should not put you off.... It is all part of the experiment. Just grab a replacement part from your junk box and start again.

Recently I started to make digital pictures as well. Especially when repairing equipment while taking it apart. Make notes on a printed picture or make the notes with your favourite photo-drawing software. It is a great help when putting the thing together again afterwards and this way less nuts and bolts are left over....

Last but not least. have lots of patience. Do not expect something to work the first time. To get it right you really have to experiment. Use the multimeter to check if all voltages are where they should be. Measure across resistors to check wether active components draw the right current. Check your soldering for shorts, dry joints and so on. When you are at a dead end, give it a rest and do something else. Your sub conscious will keep at it and it'll come to you like a flash.

Also when mounting boards and other components in a cabinet - other than a prefab kit you bought - never rush things..... Have a good look through your junk box - that may give you an idea how to make the cabinet. I make a lot of cabinets from double sided epoxy PC board. Easy to work with (hacksaw and small drill). Can be soldered together and components like small switches can be soldered on. Ideal for front plates - glue a (colour) printed front on and it looks even professional.

Hope this inspires at least one person to take up his soldering iron and discover a fascinating side of our beloved hobby.

Henk - VK2GWK (ex PAoADC)

One Mile Beach NSW - Australia