'Splainin' Things:

My Follow-up to the Lecher Wire

By

Eric P. Nichols, KL7AJ

I was elated with the response I got to my recent Lecher Wire post. As a follow up, last Friday at the March Arctic Amateur Radio Club meeting, I demonstrated my Lecher Wire. At any rate, my demonstration was equally well received in the flesh. Many of our old timers were almost tearful with nostalgia over seeing the thing, and a lot of “kids” (anyone under thirty) were totally mesmerized. We had one guy, somewhere in between say, “I've been playing with SWR bridges for twenty-five years and I never had a clue what I was actually doing. This is the first time I'd ever even heard of such a thing!”

This is what it's all about. All the textbook theory in the universe just won't give you the feel for things like actually having the hardware in your grubby little hands. This is why I love explaining things, to see the “aha!” light up the eyes of my rapt audience. The Lecher Wire is probably about as close as you're ever going to get to actually “seeing” radio waves.

I presented a little contest. After giving a basic demonstration, I asked if anyone (excluding the really old timers) would like to try to tell us what the frequency was of the R.F. signal in the thing. (I used a grid-dip oscillator to drive the Lecher Wire, and I really had no clue how accurate THAT thing was at UHF). One medium young feller came forward, and gave us the answer, which was EXACTLY right on the money. (Within the cursor thickness of my GDO, 348 MHz). I was duly impressed, not only that he got it right, never having seen the device before, but also that my 40 year old GDO was so accurate! (Confirmed later with an actual frequency counter). So it turned out my flamboyant demonstration device actually turned out to be a fairly precision instrument!

Next, I threw out another zinger. I asked what the standing wave ratio on my device was. Answers were all over the map, but a couple of guys got it right...INFINITE. So I asked the next question. “Here we have a transmission line, at UHF, with infinite standing wave ratio. How much loss do we have on it?” Again, answers were all over the map. This time I picked someone with a really WRONG answer...but someone who I thought SHOULD have known better. He boldly stated the losses would be huge.

“How would you measure that?” I prodded.

“Measure the voltage at one end and then measure it at the other,” he said, sounding a little less self-assured.

“Good answer,” I said. “Would you care to demonstrate for us?”

Fortunately my Lecher wire was a couple of wavelengths, plus some spare change, at the frequency of interest. My friend came forward, slid the meter to find a voltage peak real close to the generator, and squinted at the meter, scribbled on his mental scratch pad. He then slid it down to the far end, looking for another peak. It was IDENTICAL.

“Well, I'll be $%^*!@” he said, and returned to his seat.

Case closed.

I then put a 330 ohm termination on the end of my wire, and then showed how the meter read nearly half scale the entire length of the Lecher Wire. At first there were a few bumps in the voltage, but I then adjusted the spacing of the rods until it was absolutely flat. (By the way, for future reference, in case anyone's interested in duplicating this, two half-inch diameter copper pipes, spaced 4 inches apart, center-to-center, is real close to 330 ohms).

After coffee break, everyone wanted to come up and slide my meter around and twiddle with my GDO (another device a lot of those present had never seen before). I made my Lecher Wire big, bold, and indestructible, because I WANT people to get their grubby hands all over the thing. This is something we need to be teaching our new hams, just as much as theory.

(Incidentally, I understand a lot of our high schools have removed the actual LABORATORY from their chemistry classes. What kind of insanity is this? I know the professional worrywarts blanch at the thought that a student might suffer irreversible trauma upon experiencing a smelly chemical reaction, but good grief!) Our young people have been “virtualized” into oblivion.

More often than I care to consider I hear various hams on this forum and others say something like, “We need to get beyond the mad scientist image to really promote Amateur Radio...yada yada.”

Pray tell...WHY?????

If a young person can't be a mad scientist in ham radio, where CAN he be one? Obviously not in high school chemistry class any more. Let's face it, the young, optimistic, motivated mad scientists in Japan and China, and India and Pakistan, and Thailand and even South America are cleaning our clocks!

We can complain all we want about outsourcing and related issues. But I've worked with Indian and Chinese, and Pakistani and Malaysian undergrad students, and believe me, they GET this stuff! They have the PRINCIPLES down cold, often before they're out of high school. They don't have all the digital goodies, network analyzers and modeling software, or even DVMs that we take for granted, so they HAVE to do things the mad scientist way. (Although, not too surprisingly, it's easier to get actual electronic components in India than it is in Radio Shack, these days).

One of the reasons (if not THE major reason) amateur radio exists is to be a font of knowledge and technical expertise, upon which society as a whole may draw in both good times and bad. Amateur radio has a golden opportunity to take over where the educational systems and government are failing. Young radio amateurs should emerge from our ranks with a real grasp of how this universe is held together and the ability to lead this country again into technical prominence. If THAT doesn't qualify as public service, then, pray tell, what does!

You see, the Lecher Wire is more than two pieces of copper. It displays the law and order inherently built into the physical universe. It is not subject to politics, fad, fashion, or rhetoric. A Democrat or a Republican will obtain exactly the same results with a Lecher Wire. A Christian or a Muslim will obtain exactly the same results with a Lecher Wire. An old geezer like me and my pink-and lavender-haired teenage daughter both get identical results with the Lecher Wire.

How many other things in life are so reliable and constant?

Respectfully submitted,

Eric P. Nichols, KL7AJ