"Mom, can I stop by Mr. Tom's on my way home from school?" "Oh Jeff,I don't know. I don't like you hanging around that guy too much. He's so... well... strange." "Mom, I've told you... he's not strange, he just doesn't watch TV. He's really smart, and besides, it's on the way." "Oh, OK, but don't you be late for dinner, we're having your father's favorite." "Oh great," I thought to myself. I don't know what it is this week, but dad's favorites are usually something pretty gross.

Mr. Tom is a friend of mine. He's a ham radio operator, and doesn't seem to have many friends... at least not in the neighborhood. Most people think he's a grumpy old man, but they don't know him like I do. Tom just acts grumpy. I think because he's old, and life isn't like it used to be. At least that's what he always says.

RINNNGGG -- "All right class, before you go, pick up any scrap paper off the floor around your desks, and I'll see you tomorrow. "Yeah, yeah, yeah... just let me out of here," I thought to myself. It's 3:00 and I have to be home at 5:00 for dinner. "It takes 20 minutes to get to Tom's, and 10 minutes home from there. That would give me, what, an hour or so?"

Tom sure has a neat hamshack. Well... it really messy, but he has alot of neat stuff in it. I've seen him use computers to talk to people by typing on a keyboard, and sometimes he uses satellites. He shows me on a computer screen where the satellite is, and where the guy is that he is talking to, and it's usually somewhere far away. Tom also talks to people using Morse code. I think he does that a lot, but when he has visitors, he uses a microphone so they can tell what he is saying. Most of the people he talks to are in other countries, but they always speak English. Some of them aren't too good at it, but nobody minds.

KNOCK, KNOCK, KNOCK -- "Yeah? What do you want?" "Hi Mr. Tom. I just wondered if you were gonna work any DX today?" (I had learned that speaking his language helps). "What?... DX?... Who are you, boy?" "Mr. Tom, it's me, Jeff, I live up the street." "Oh yeah? Ya like radios, do ya, boy?" "Yessir, I sure do!" We have this same conversation about twice a week. "Well, all right, come on in and lets see."

Every time I go in Tom's shack, it's a thrill. He has so much neatstuff, and every time, there is something different. Today, he had a radio that looked really old there in the operating position. That's the only part of the bench that's ever neat.

I noticed near the radio, about a half dozen devices, all similar in appearance. They looked like old tubes, but were metal instead of glass. I picked one up... a risky move around old Tom. "What's this, Mr. Tom?" "Don't drop that thing, boy!" "OK, I'll be careful, but what is it?" "It's an I F filter. Ya plug one in the socket here in the back of this radio right here. There's new-fangled radios now that have these built in. You pick which one to use by pushing buttons on the front." "Oh... well, what do they do?" "WHAT! What do they do? You don't know nothin' about no radios, and bandwidth, do ya, boy? How old are ya, anyway?" "I'm eleven, and in the sixth grade." I just put the grade bit in because I knew it was his next question. It always is.

"OK, well, looky here now. See this chart along the top of the wall? It goes all the way from the door to that window over there. Ya see that?" "Yep." "Well that's the electromagnetic spectrum chart. It shows what different frequencies are used for. Low frequencies with long wavelengths are at the left end down there by the door, and higher frequencies go to the right. It goes all the way up to 150 megahertz. That's two meters. Some guys use frequencies higher than that!" "Wow! Well, what do these filters do?" "OK, now listen to me!"

"What a radio does, is let you 'see' a part of the spectrum with your ears. When you turn the tuning knob, you change where on this chart you are 'looking'. Ya see that boy?" "Yeah, but what about the filters?" "All right! all right... I'm getting to that. See, this chart is about fifteen feet long, and the radio lets you 'see' through a 'slot' of the spectrum. These filters determine how wide that 'slot' is. Ya see, the dial on this radio is set to a frequency, but the radio actually hears that frequency, plus all the frequencies above and below that one for a ways. The further above and below... the wider the slot on this chart." "Why do we care how wide the slot is?" "Why do we... agh, geez... What are they teaching you in school, anything? We care because different types of radio signals take up different amounts of the spectrum. See, this dial shows a frequency. That's the center frequency. When I talk into the mic, I take up that frequency, plus all the frequencies above and below that. How far above and below depends on what mode I'm using. Here, listen to these guys here squawking on single-sideband. They use up between two and three kilohertz on the chart, so I plug in a three kilohertz filter back here. Now, if I tune around, you can hear a different conversation about every three kilohertz up the band. See, their bandwidth is about two and a half kilohertz, I guess. Now let's tune down here to the other end of the band where the Morse code is. OK, see? Right here I can hear three different conversations going on at the same time, but each is at a different pitch coming from the speaker."

I had to ask, "Well, why do we hear three conversations?" "It's because the 'slot' we're looking through is three kilohertz wide, and these fellows are only about one kilohertz apart on their dials, so several come through at once." "Well, aren't they interfering with each other?" "No. You're forgetting about the filter. Look, gimme that one marked 500 on it. It is only half a kilohertz wide... a narrow slot indeed. Now all I do is remove this 3K filter, and plug in the 500, and now look, only one station." I jumped in with "So if I wanna hear the other conversations, I gotta turn the knob, right?" "Yeah... you're learning now! Ya see how much closer together these conversations are? Only one kilohertz, instead of the three you have on sideband. That means more people can fit on the band." "Well, if Morse code uses so much less space, then why doesn't everybody use it?" "Cause everybody doesn't enjoy it... and there's enough room for everybody to work whatever mode they want. At least for now."

"You sure ask a lot of questions, don't ya, boy?" "I guess, but I won't ask any more today, it's nearly dinner time, and I've got to get home." "Well don't rush off... don't ya wanna know about this stuff over here?" "Some other time Mr. Tom. If I'm not home to watch pop eat his favorite dinner, I won't be able to come around no more." "OK Jeff. You better git then." "Yeah, bye Mr. Tom." "73 kid."