Man, what a long day! Work is so tedious sometimes. This week I’ve been proofing scientific literature (revising scientific manuscripts in an attempt to improve them as much as possible to increase their probability of acceptance and timely publication). I’ve been using Office 2003 (with “track changes”) to do this. I make changes, my boss makes changes, I make more changes, and it goes back and forth a few times. I wonder why office 2007 is so bad. Does anybody truly like it, and find it to be a significant improvement upon 2003? … or Vista over XP? [sigh] Maybe I’m just getting old, inflexible, and grumpy.
Here, take a look at what I’m working on [snapps screenshot]. I had to blur the content for intellectual property protection and to avoid possible future copyright violations. The light bubbles on the right are deletions. The dark bubbles on the right are comments. The red text is insertions/modifications I made. Pretty intense, huh? Pages and pages of this. And, upon successful completion of a manuscript, my reward is to begin working on another one! Luckily we’re almost caught-up on manuscripts… but that means we get to start writing grants… I’m starting to grasp the daunting amount of time a scientist must spend writing in the laboratory as opposed to performing actual experiments or even doing literature research.
Last night I assembled a Pixie II circuit similar to the one pictured here. I must say that I’m a little disappointed with the information available on the internet regarding simple RF theory in relation to transceiver circuits. I’m probably just not looking in the right places though. (Yes, I know about the ARRL handbook.) The thing is that I’m just now starting to get into RF circuitry and the concept looking at solid-state circuits and imagining a combination of AC and DC flowing through it is warping my brain. I have everything I need to build an ultra-simple Pixie II transceiver (which is supposedly capable of morse code transmissions over 300 miles, and QRSS applications over 3,000 miles) but I refuse to use it. No, it’s not because of moral obligations preventing me from powering it up before I get a general class radio license (shhhh). It’s because building something is useless unless you understand what you’re building.
I’m trying to break this circuit down into its primary components. I understand the role of the lowpass pi filter (before antenna). I understand the role of the 1st transistor and related circuitry in amplifying the output of the oscillator (left side). I totally get the audio amplifier circuitry (bottom). It’s that center transistor (which supposedly handles signal amplification, receiving, and mixing) that I can’t get my mind around. Every time I think figure it out for one mode (sending or receiving), I lose the other one, and visa versa. It has me very frustrated (and a little depressed about the whole thing) because this should be much easier than I’m making it. There’s no thourough documentation on this circuit! I selected it because it was extremely simple and I assumed I’d be smart enough to figure it out. I guess I was wrong. I wish I had an oscilloscope so I could probe the RF passing through various stages of this circuit [sigh]. Back to the ARRL handbook. Maybe if I read chapters 5-11 a couple more times I’ll magically understand it.