I found Ward Silver's article on
vacuum tubes in the November 2017
issue very interesting. Nobody gave
me high voltage safety rules when I
started messing with that stuff, like
"High voltage is not for beginners"
and "Working with high voltage
requires the maturity and patience
that comes with age and experience."
Now, I have the experience and
definitely the age, but I’m not so sure
I have achieved the maturity and
I built my first radios using tubes
when I was 11 or 12. When I was 15,
I bought a pre-WWII 250 watt AM rig
from an old ham who was changing
over to a Johnson Viking I. It used
type 812 triodes in the final, and
type 811 triodes in the modulator. It
was in an open rack six feet tall, and
the power transformer probably
weighed 20 pounds.
Four 866 mercury vapor rectifiers
in a bridge configuration (three
filament transformers) generated
1,000 volts at a whole lot of current.
TVI was something of a problem, and
after a few months, I rebuilt the
whole thing from scratch in a Bud
cabinet, using all the original coils,
tuning capacitors, tubes, transformers,
While I was in high school, I used
it extensively on 40 meters (phone
and CW) and 10 meters, and a little
bit on 80 and 20 meters. The rig
never got used again after I started
college in 1954. The tubes,
capacitors, coils, and some of the
transformers were sold at a garage
sale in 2000.
I never got an electrical shock
from that rig, although even then I
was not new to being shocked. I have
certainly been shocked plenty times
since, and know that 24 KV from a
CRT power supply makes it seem like
my ears are flapping!
Jerry Nicholson W0FJC
Your comments are well taken.
I too grew up with high voltages
within inches of my face — homebrew
2 KW SSB amp, 450W 2M transmitter,
etc. Glad you lived this long!
Seriously, great info for readers!
Words of Wisdom
Based on Bryan Bergeron’s
editorial in the November 2017 issue,
it sounds as though he has a nice lab.
Inspired by his column, here are a
few words of wisdom based on many
1. Use good power supplies that
offer adjustable and fixed voltages. I
prefer analog meters on my supplies
because they respond quickly to
changes, and don't confuse me with
unneeded fractional digits. Get the
best supplies you can afford.
2. Use commercial-grade metal
plug strips, not the plastic types that
can easily break in a lab. Some of
these metal strips include a circuit
breaker. The receptacles have enough
space between them to
accommodate oddly positioned plugs
and bulky wall wart modules.
3. ALWAYS have your lab power
on a ground-fault circuit breaker. No
exceptions! It can save your life.
4. Work on a properly grounded
static-dissipating mat. Ground yourself
with a wrist strap when you work
with components a static discharge
5. Have a fire extinguisher close
Jon Titus KZ1G
Appreciate the words of wisdom.
I follow all but #1, simply
because I gave away my good analog
metered supplies to friends and
replaced them with high quality
digital metered supplies. Digital is
handy when working with
microcontrollers that are finicky about
First of all, I've been an avid Nuts
& Volts subscriber/reader way back
to when it was awkwardly large. So,
bottom line, my heart does a little
happy dance whenever a new issue
Regarding Bryan Bergeron’s
December 2017 editorial titled,
"What Your Preferred MPU/MCU
Says About You," as far as I'm
concerned, there were some hits and
misses. And, since he seemed to
invite comments — though, not
specifically on the topic he requested
— nevertheless, I offer the following:
I've used the PIC MCU since
they needed to be erased with UV.
My continued use has everything to
do with reducing manufacturing
costs. So, it's true that this user is "old
I don't remember why I selected
the PIC in the first place. Maybe
because of the relatively low start-up
cost (the PICKit2 was cheap and
MPLAB was free if you were willing
to code in assembly, which I was —
for awhile. Then, I sprung for the CCS
I think it was mainly because
back then, it was either the only
MCU on the block, or it had the
greatest popularity and thus the best
Bergeron was also right that I
don't chase after "greener grass."
When I start a design, I look for the
best PIC fit for the requirements,
which typically means a different
device for each project, and often
that comes with a learning curve.
Currently, I use the mikroC
development system which
occasionally — by using the included
libraries — makes adoption of a
different PIC flavor a little easier, but
their libraries are minimally
implemented. Typically, I have to do
my own implementation to get the
result I want.
For instance, I was unable to
communicate with an AD5292 digital
pot using their SPI library. They just
didn't provide the configuration
needed to do the job, so I rolled my
own, and got it working.
For two reasons, I recently
evaluated the Arduino (Uno and Mini
Pro) as a possible alternative
6 January 2018