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What is the point of ham radio
radio : by Tommy - October 16, 2017, 09:14AM
I hear this question quite a bit. "What's the point of ham radio?" usually tied in with "You know you can just pick up a phone and call someone right?" or "The internet lets you chat across the globe too, you know?"
Yes, I know it's possible to accomplish a task in a seemingly more efficient way, but that's not what makes ham radio interesting. Whatís the point of sailing, fishing, rock climbing, hiking, gaming, hunting, knitting, auto racing...? There are more efficient methods of travel, attaining food, clothing, etc. So what's the point of any hobby, really? Those who enjoy the hobby will say "it's fun", but that's not a very clear answer because what is fun to one person is boring to another.

With ham radio, like any other hobby, it's a pastime - one that happens to have a lot of electronic underpinnings.

In fact, I liken it to catch-and-release fishing more than chatting or phone calls. Yes, you talk to people, but the majority of hams donít care about the content of the conversation as much as where the other party is.
In my fishing analogy, I say casting out your lure is like calling out on the radio. "Will I get a bite?" = "Will someone hear me?"

Someone probably will hear you and answer your call. So you respond and find out how well they're able to hear you, where they're from, and perhaps some other information about them. That's like reeling in a fish to measure and weigh them. "Wow! This guy's in the mountains of Nepal!"/"Wow, what a big fish!"
Sometimes the "fish" isnít very big, the radio contact may be relatively close distance to you, so you say so-long and "cast" again - hoping for bigger fish.
Or maybe a rare fish...
Or a hard-to-catch fish...
Or a relatively famous fish...
Or maybe you want to try fishing with different equipment (bigger, smaller, new technology, relay through a satellite, etc) and see if that helps or hurts what you "reel in".

Continue reading...

tags: ham radio diy

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7400 Oscillator
hardware : by Tommy - January 21st 2013, 10:51PM
I recently came across a schematic that showed how to build an oscillator using the NAND gates inside a 7400 chip. After poking around online, looking for the 7400 (and not some variant) I learned the LeTourneau University College of Engineering has a parts supply closet with a whole stash of them for 5Ę each. (I've known about the parts closet for quite a number of years, but only recently discovered a tall filing cabinet full of most commonly used ICs. (No NE602 or 612s, I'm afraid, but that's another post for another time.)

So, with my 7400 in hand, I was able to breadboard an oscillator using the "colorburst" crystal at 3.579 MHz. The oscillator emits a square wave at the fundamental frequency, so harmonics abound. In fact, just through playing around with another receiver, the 3rd harmonic at ~28.632 MHz is considerably stronger than the others that fall in the ham bands. (All higher harmonics are just above the ham bands, though I may be able to pull them back down with a variable capacitor in series with the crystal.) I need to do some range testing on this to see just how far I can get on the various bands.
My next trick is to build a bandpass filter network to dampen the harmonics down to legal levels. Then, I'll have a bona fide transmitter, though very, very low power. Perhaps a final amplifier is on the drawing board next.

tags: electronics diy radio

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