Independent Projects

1974-1978

As a  young kid I loved to take apart anything to see how it worked...the telephone, my sisters music box, a portable radio, etc... much to the dismay of my mother.
My dad helped me build a simple crystal radio then he taught me how to read schematics and gave me a schematic from a QST article and said "see if you can build this".  It was the "octopus" a simple circuit for checking semiconductor junctions using an oscilloscope.  I had to find a box, select the parts, do a physical layout, then solder it all up.  It worked!  I was thrilled!
I then built a code practice oscillator using some GE-2 Germanium transistors dad had in his junk box (I might still have a couple!). I really liked this electronic stuff.
So dad bought me a book of electronic projects and I proceeded to build each one.  I scraped together all the cash I could from mowing lawns, and working for Dad in his side business of making the wood parts for antique cars (model A's mostly). I even spent one hot July de-tasseling corn for a whopping $5.00/hour, double that if we worked Sundays, which we did of course. Pretty good money for an 8th grader.
Anyway, one of the high lights from that book that I wish I still had was:

A super regenerative shortwave receiver that covered 3.9MHz to 15 MHz.  It used only two active parts, here are some of the main components:

Some other projects of my youth: 1976 got my ham license, Built a two tube 180 WATT 5 band CW transmitter, used a heathkit 5 band VFO dad had packed away in the attic.  That attic was a treasure trove to me.

1978-1980

Found a pile of data books at a church bazaar book sale.  This fired up my electronics interest big time.  All those app notes where GREAT!  Some of the books I remember (and maybe still have):


Designed and built a solid state QRP CW transceiver. I basically took lots of individual schematics I found in QST and the motorola data books and put them together to make a transceiver.  Some key features:

First contact was with a station in Ohio, got a 599 report, he did not believe I was running only 5 watts.
Other contacts where as far away as europe.  Made a total of maybe 10 contacts with it and then I got bored with it and never turned it on again.

I built an analog SSTV (slow scan TV) display based on a circuit in QST, but I used 741 opamps and an NE565 PLL instead of the 88mH toroids (yuk!), tubes and transistors -- that signetics application manual came in handy!  It used the oscilloscope as the video display.  It seemed to work but I couldn't afford a new CRT tube with the long persistant phosphorus for the scope. I could only use it in a totally dark room by cranking the brightness up and seeing just a small band of the image as it painted down the scope face.   I spent a bit of time doing that since all those old farts  with the SSTV stations (and especially those Italian stations) seemed to send a lot of center fold type pictures.... HA!  Who said being a geek was sheltering!
 

1980

Got my extra class amateur radio license -- KO0F. It was my goal to get that before heading to college, since I figured I would never have time to do it, and wouldn't be interested enough to go for it in the future. I wanted it just to be able to say I did it.
Designed and built an 8080 computer which featured:

Later that year I updated my computer with the following features:

Built a 16 character one line video ASCII display that used an oscilloscope as the video monitor.  This board was based on the "Scopewriter" (POPULAR ELECTRONICS, August 1974) I used the following chips: Added a 8251 UART with a tunable NE555 for the baud clock.
Designed tunable RTTY demodulator using NE565 PLL.
Designed and coded software to display Reuters HF news wire transmission and display them as scrolling text on the "Scopewriter" ASCII display.  The first headline that scrolled across was "Sudan:  Hut falls on man, killing him."  I thought that was a strange news item.... A hut?  No explanation, that was all it said.

Built other misc. circuits for the ham radio hobby based on articles in the QST magazine.

1981 a busy year...

More updates to my computer....

Added 16K of DRAM (from a scrapped Memory card I bought for $2.00 at a hamfest, I think it came from control data.  I reverse engineered the schematic using a DVM and National Semiconductor's data books.  It worked great!)
Added four S-100 expansion slots.
Added an S-100 8K byte video display card that could display ASCII (40x25)  or graphics, the highest mode being 128x128 and 16 colors (or grays on a black and white TV converted to a monitor.).
Designed and built a new SSTV demodulator using an ne565 PLL and an 8bit  Analog to Digital Converter. (Basically a Frequency to Voltage converter).  I built this so I could see the images from the Voyager space craft that the JPL ham radio station sent out as soon as they got them.  Man was that cool!!!  I still have the cassette tapes with the SSTV images recorded off the radio.
Designed and coded the software to decode the SSTV signals and display the images.
Added Ascii keyboard.
Designed and coded RTTY transmit and receive software using the new video display and ASCII keyboard. Dad (W0CXG) really like the RTTY program I wrote  and used it a lot while I was at school.  He made me write a user manual giving step by step instruction on how to load the program from the cassette tape and how to enter the call address to fire it up, plus details on all the function keys.  This was very valuable experience on how to document and how to make a user interface more friendly.
Designed a single pass compiler. (i.e. Type in the instruction mnemonics instead of hex.)
Designed a full screen text editor to edit and save assembly code.
 

1982

I started college.  I got a Heathkit H89 computer with 32K RAM.  Dad bought it just before he died. I was both very happy and very sad.   We talked about all the fun stuff we were going to do with the H89.  I ported my original RTTY program over to the H89 and added lots of improvements, I had 90K of space on the floppy drive!  WOW!  The H89 came in very handy for all the papers I had to write. I was one of the few lucky folks that didn't have to use a typewrite and could edit electronically.  It came in VERY handy for all the C programming assignments, I didn't have to wait in line for a small amount of time on the university terminals in the computer center.  I'm sure I got a lot more sleep than most folks...THANKS DAD!!!!
I spent many nights reading the news groups using a 2400 baud prototype modem I got from my buddy who worked at multitech.

1983

Started upgrading the H89....

Increased the memory to 64K DRAM.
Increased the CPU speed from 2MHz to 4MHz, software controlled.
Rewrote the CP/M BDOS to fix all the timing loops that got goofed up at 4 MHz.  Good thing heathkit provided all the source code for CP/M back then...
Added a second floppy drive.
Disassembled a number of comercial programs and added my own features.  (And to fix their hard coded timing loops.)
Wrote a BASIC program for scheduling people's work hours at a pizza place I worked at, it did  much of the scheduling automatically based on profiles for each employee. It took into account which teams of people worked well together and which ones didn't.  The store manager thought it was great!.  But the upper management wasn't interested.  Oh well. I was ahead of the times I guess.
Added a battery backed real time clock.  Modified the BDOS again to support it.  The last time I fired up the H89 cpu card, after it had been off for 5 years,  the clock was still within 3 minutes.  Amazing!  I think that was in 1993 -- the last time I had it on.
 

1984

Got a REAL job at 3M!  I worked part time in between classes and in the evenings.
 

1985

Got the heck out of school (with EE degree in hand!).
Upgraded the CPU card in the H89 to an 8 MHz AMPRO Z80, with 360K IBM compatible floppy suport!  I got it dirt cheap, all those IBM clones where killing the CP/M Z80 market.  It was a boat anchor before it arrived, of course.  But we still used Z80's a lot in the embedded stuff at work, so it was a great developement system.
 

1986

Bought an IBM XT clone for $600 -- WITH a 12 MHz turbo button!  Started doing consulting on the side writing drivers for PC add-in cards.  Boy, I hated that stupid Intel 8086 architecture.  The 68000 was so much cleaner!  What idiot picked the intel processor?!  You had to access the memory in 64K chunks!?  Yuk, its little more than a bank selecting 8080!   The 68000 was so much cleaner!!!   Too bad business people were  so technically deficient and didn't embrace the apple mac, too bad apple was so stupid in its marketing!
 

1988

I wanted to get up to speed on this C++ stuff, so I wrote a C++ program to control my Yaesu and Icom radios from the serial port.  Created a base radio class then derived a yaesu class and an icom class.  Later added a kenwood class, but never tested it. I still use that program, it has a simple database for logging interesting stations, and of course it can do scanning and such.
 

1989

Started spending the big bucks (ha!) I was making on off the shelf stuff instead of building it myself. I did enough designing at work, I figured.   I was amazed at all the Mighty Fine Junk there was out there.  People could actually sell this stuff?!  Hmmmm..... I should start selling my stuff, it works better IMHO.  I haven't yet...
 
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