Old Projects

First Project

ESZ-4000 Satnav, Satellite Navigation Computer.

(Click on Photo, below, to open PDF brochure – 2.13MB):


Actually, I did NO engineering work on this one. I was just a kid starting college, and was hired as the low man on the totem pole. So I did everything else, such as: wire up test circuits, draw schematics (on a drafting table with a pencil; No CAD), and verify PCB artwork (also hand taped; No CAD). As being the low man, I also, ran errands, such as getting the engineers their lunches, pick up parts and supplies, and pack parcels then take them to the local UPS or FedEx depots. The 2nd ‘Oil Crunch’ was also happening (1979), so I also waited in line for gas, with the bosses car.

In addition to gaining experience in electronics, I learned about geoid height. Sea level varies, not just with tides, but because the Earth’s density is not uniform, gravity varies at different locations, so the mean tide varies accordingly. There are actual hills and valleys on the oceans’ surface, made of water.

The company, I worked for, did the engineering, for the manufacturer (Navidyne), who was based in Virginia. This museum site is the only other place on the web, that shows a photo of the unit.

Several years later, Navidyne asked us to design a Loran receiver for them. This became the ESZ-7000 (Click on Photo, below, to open PDF Brochure):


Loran-C was a ground based navigation system. It gave better precision than satellite systems, plus signal was always present, when in range of land. A satellite may not be in range, at times. Loran was used, when close to port.

My employer specialized in “computerizing” products, which was relatively new at the time. Everything now, has a computer in it. That wasn’t always the case. A computer implies software, so we wrote a lot of code. Initially, in assembly, almost exclusively. But over a certain size, using a high level language improves productivity. So, in the early eighties, one of the bosses, adapted Forth, to embedded control (it wasn’t know as that, at the time). It worked out well, and was pretty slick, so the company offered it as a product (click on Photo to open PDF Brochure):


We used two models of Tektronix development systems, to develop our projects. The 8002, and the newer 8550. These computers had emulator pods, that plugged into processor IC socket, on your target hardware. Tektronix made the full systems, including OS. Tektronix should stick to instruments, and stay away from computers. These were slow dogs compared to the contemporary CP/M computers. Years later, in the IBM PC era, emulator makers, just made the pod, and they plugged into a PC, by way of a COM port (pre USB). Now I just use a small ISP dongle, that plugs into a USB port. The Tektronix units (and their HP 64000 competitor) cost in the $10K+, range. Often closer to $20K. An emulator that plugged into a PC cost between $2K to $5K, in the mid-80s, to early 90’s. An evaluation board for the Motorola HC05, worked better than those early development systems. it plugged into a PC, via a COM port and only cost me $500. The AVR ISP (now discontinued) that I currently use, only cost me $30. Times have changed !

As a last hurrah, the company designed a ‘smart’ mixing board. One of the bosses (the one who wrote the ProForth Compiler) was a musician, and did his own multi-track recording, so we designed this mixing board for him (he wrote just about all the code). On the side, we tried to sell it as a product to others interested.

(click on photo, to open PDF brochure):


This unit communicated with a MIDI Sequencer, to record the mixing session. No audio went to the actual panel. The fader data was sent serially to a central module, where the audio level was adjusted thru VCA (voltage controlled amplifiers).

The irony of thing was that the popularity of microprocessor technology doomed the company. Instead of temporarily hiring a company to design the product, companies built up their own in-house capabilities in this area. The company closed its doors, in spring of 1988. Those of us too young to retire, found new jobs with our former customers.

My next employer was a customer of my former employer, Magnasync. This was, and then again, was paired up with famous name Moviola. Often referred to as Magnasync-Moviola. Moviola made film editing equipment, while Magnasync’s primary product, from the 70’s on, were voice logging recorders. My prior employers assistance was to put it under computer control. What is now called embedded control. Magnsync’s prior models were the 1500, 1700, & 2000. The new model, released in late 1981 was the Specialist.


(Click on photo, above, to open Brochure)

These recorders, were analog, and recorded upto 60 voice channels, on a 1″ wide 3600ft long tape, on 10″ reels, that held 25 hours. There was also a time track, that could be used for later searching, for specific playback. A search was a sight to see ! Those tape reels were massive, an you could lose a finger, if you got your hand in the way ! To ensure, that each channel was properly recording, each a fail-safe tone recorded onto the tape continuously. These tones where subaudible, but detectable by the units circuitry. These were rock solid units. Unfortunately, they had their own y2K-ish problems. The time code originally used, was IRIG-E, but that was replaced with Magnasync’s own proprietary code. This code, extracted down to a 32-bit number, with 0=Jan 1, 1984, in seconds. That timecode overflowed sometime in early 2013. I left the company in the mid-90s, to work for Comverse Technologies, which had its own soap-opera-ish adventures !