Wednesday, May 23, 2012

Handiham World for 23 May 2012

Welcome to Handiham World.

You can do it!  

Today, just as we did last week,  we are going to begin with Troubleshooting 101 as part of our initiative to help new ham radio operators (and even some of us older ones) learn how to do some basic troubleshooting for ourselves. Yes, it can be tempting to ask someone else to do things for us.  This can become a bad habit when it keeps us from learning new things, especially things that we could - with a bit of practice - learn to do for ourselves.  Knowing these basic things can serve us well in the future when no help is available. 

Troubleshooting 101

Let's get to today's troubleshooting question: 

Question: This question has to do with my workshop. Let me explain; over the years I have collected quite a few electronic parts and lots of hardware used in electronics and computers. While I have built some projects in the past and have done some repairs on various pieces of equipment, it seems like I seldom use many of these parts that I have saved up. My wife told me that the basement is getting to be kind of a mess and that I should clean out some of the "extra junk" from my shop. My question is, "How does one decide what to keep and what to throw away?"

Interestingly enough, I was just thinking about this very problem recently. It seems like whenever I have to work on something in my own shop, almost invariably I will have to go out and buy something to complete the repair or project. I am almost never able to pick something out of my junk box and make it work. Since I have been an amateur radio operator for decades, I have saved up a collection of really good stuff that I am possibly going to use some day – for something. The problem is that I have stuff that has been in the same place in the shop for 20 years and has never been touched. Now, you may be thinking that my workshop is such a mess that I just can't find anything. That is not the case. I pretty much know where things are, but I just don't seem to ever need them for a project or repair even though that is the reason I am keeping them.

Does any of this sound familiar?

I'll bet it does; just about every other amateur radio operator does exactly the same thing. We might find an interesting treasure at a hamfest or swap meet, but we really don't know what we would do with it other than use it for a project that never seems to materialize. So to answer the question, you need to come to terms with the reality of the situation. Let's lay it out and be as honest as possible:
  • Technology advancement: Technology has marched on, but your junk box collection has not. The fact of the matter is that most of the stuff you have collected might have been good for fixing electronic equipment that was in vogue 20 years ago or more. Today's electronics use different kinds of parts and sometimes are not even user-repairable. Those vacuum tubes and wire wound resistors in that box underneath the workbench are probably not going to be much good to anyone but a person who restores old radios. If you are not such a person, then it is time to get rid of those kinds of parts. I could go on about other parts for radios and computers, but you get the general idea. If it is not likely to be used in current technology, get rid of it. 
  • Time is limited: Be honest about your time. You do not have unlimited time. You're busy, perhaps busier than you have ever been, especially if you are still in your working years and are raising a family. Do you really have time to work on projects that will take many hours or even weeks or months to complete? It may be better to pare down your collection of project parts and keep only the most essential. Your reward for doing this is a tidier shop and less clutter. This will make it easier to do the projects that you do actually have time to complete.
  • Your interests have changed: At one time you were interested in packet radio and by gosh, you still have that old terminal node controller on the shelf. Along with that, there is an old computer that used to run DOS and that would be "perfect" for your packet station. After seeing a club program about rhombic antennas, you decided to start collecting wire to make that rhombic antenna someday. Of course, you are also interested in getting several of those old computers you have saved back into service. Maybe you can put Linux on them. Well, guess what? If you haven't done anything with these items for several years, your interests have probably changed and you are not likely to get around to any of these projects – ever. Give as much of this stuff away as possible and recycle the rest. Most counties and municipalities have some kind of recycling program for computers and electronics.
Just how honest can you be with yourself? After years of collecting all this junk, it can be difficult to admit that you are never going to get around to using any of it and that you are better off just getting the workshop cleaned out and tidied up so that you will have more space to work and less clutter.
Over the years I have seen some real junk collections. A few of them have been jaw-droppingly amazingly enormous collections worthy of being a swap meet in and of themselves. I could never imagine how anyone could have deluded themselves to the point that they actually believed all of this stuff would someday be useful! It would've been impossible for the person to use half of this stuff in two lifetimes, let alone one lifetime. One guy, an elderly gentleman, had a basement full of shelves arranged in rows, all stacked with equipment and parts at least 30 years old. Another had a basement and an additional storage building with row upon row of shelves holding old parts and radio gear. It is not as uncommon as you might think.

We have to face up to the fact that keeping things simple, actually expedites project-building and troubleshooting. When you have too much stuff, you waste time moving it around or digging through it to find some little part you think you might have. This is usually not worth the time and effort. You are better off buying a new part that will be exactly the right one when you need it. Furthermore, too much junk and clutter can make you prone to simply putting off a troubleshooting project because it is too much effort to work in your shop. If that is the case, you REALLY need to do some serious organizing.

At Radio Camp we will be talking about the essentials of a good, efficient home workbench. We won't go into this lean and mean list of shop basics right now, but I will reveal that it is surprising how little one needs to have a really effective troubleshooting and project space.

Email me at with your questions & comments.   
Patrick Tice, WA0TDA
Handiham Manager

A dip in the pool

It's time to test our knowledge by taking a dip in the pool - the question pool, that is! 

Today we are taking a question from the Extra Class pool:

E4C09 asks: "Which of the following is most likely to be the limiting condition for sensitivity in a modern communications receiver operating at 14 MHz?"

Possible answers are:

A. The noise figure of the RF amplifier
B. Mixer noise
C. Conversion noise
D. Atmospheric noise

Long ago, when receivers used vacuum tubes and discrete components and when a VFO could drift like a rowboat in a hurricane, we reveled in the "good old days" of radio.  Yes, these were the times when we sometimes listened with our hand on the tuning knob, either to follow a drifting signal or to try to find a sweet spot where we might hear a signal through all the noise.  In retrospect, they were really "the bad old days", because our equipment is so much better now.  Receivers are so good that they have noise figures below noise that would occur naturally in the atmosphere and stability that rivals crystal control. Thanks to these advances atmospheric noise is now the biggest worry, so answer D is correct. In essence, engineers have done everything possible to the receiver itself to eliminate internally generated noise. It's hard to do much about atmospheric noise, but now modes of operation have evolved to fight back against poor conditions.  PSK-31, for example, is amazing - it works even on days when you would be hard pressed to hear a CW signal. As far as receivers go, if you are looking for the good old days, we are living in them right now!