Jim Wilkins wrote:
"Michael A Terrell" wrote in message
...

They hired an expert in RF system design from a college, since it
was their first 'Million Dollar Headend'. It looked like it was laid
out by a drunken teenager who had only seen an I-pad.

My degree is in Chemistry, a very hands-on field in which you may not
have an assistant, so we learned the practice as well as the theory.


This guy was a professor who was teaching CATV system design. I
wrote a simple program in Basic for a Commodore 64 computer to calculate
cable loss, and the insertion loss of line taps. You could select any
brand of hardline, in any available size by the OEM part number, along
with the taps by their OEM numbers. You entered the source level, and
the amplifier gains, then the distance between taps, and the number of
ports at each tap. It also allowed multiple bridging outputs per trunk
amplifier, and to help decide which direction it was to be run from.
Sometimes it allowed you to eliminate an expensive line extender
amplifier. Every amplifier you could eliminate from the design reduced
the electrical load, and improved system reliability. The electric
company charged you for a full line load from each of the 60 VAC, 30A
modified square wave power transformers, rather than meter the power
input for each. They were ferro-resonant transformers made famous bu Sola.

It did the strand map information in seconds, that took this bozo
hours to do. The only assistant in this type of work was someone who
drew the actual maps that showed the location f the hardware on
existing, and private poles, or underground installs.

I designed an interconnect between two CATV systems for their
community loops, to provide a private system for the local schools. I
did all of the calculations, and calibrated the equipment before it was
installed. I was only off by .25 dB at the interconnect site, and they
entire system was in spec at initial turn-on.



I haven't often seen the same from many recent electrical and
mechanical engineering graduates or the co-op undergrads I rode herd
on. After they left I redesigned their circuits with half the
components, which mattered when packed into a Xilinx chip.

https://www.wpi.edu/student-experien...lopment/co-ops

I picked up a lot of practical knowledge from the manufacturers' data
sheets I studied to learn how to use their products. Switches and
fuses for instance aren't that simple if you need to push their
capabilities while expecting long life.
http://www.littelfuse.com/~/media/au..._fuseology.pdf
One young engineer kept asking me for Polaroid scope camera film by
the case, until I showed him that data sheet which answered all his
questions.

The 30A output breaker on my welding transformer power supply can
hold 70A for a few seconds, to quickly measure diode drop etc. At
300A it's rated to open but not necessarily to close ever again.
-jsw

I have close to 200 databooks in paper format, and thousands of
datasheets or databooks in PDF files here at home.

I found design errors in many older products at Microdyne, and came
close to being fired over it, several times because the older engineers
were furious that a tech had the nerve to point out a ten yer old mistake.

There is currently a thread on a Facebook group where someone used
two short SFE 32 VDC automotive fuses in series to replace a 3AG/AGC 250
volt fuse. The idiots think that it's cool, and or funny. those 32 volt
fuses will not open reliably at 250 volts. According to the long
standing data, the first to open will create a ball of plasma, and keep
conducting. The heat will destroy the fuseholder, and the fire can
spread into the wiring, and on to the surroundings.