The year was 1941 and the radio industry
was going strong worldwide. Sales of receivers was hitting new highs every quarter
and service shops had all the work they could handle for repair, upgrades, and installations.
The radio broadcast realm was scrambling to build new studios, install transmitters
and antennas, hire announcers and managers, and upgrade to keep up with the quickly
evolving business. Take a look at these 24 full pages of
products offered by the Sears, Roebuck Company in their Fall and Winter 1941-1942
catalog. It is typical of most radio manufacturers' catalogs of the era. For the
last decade engineers had been working overtime to satisfy consumer demand for fancier
cabinet designs with fancier features. So strong was public demand that people put
their highest priority on acquiring the latest models (not unlike the smartphone
craze of today). Then, ...
Every once in a while an RF Cafe visitor
writes to let me know that he or she found one of the vintage electronics magazine
articles I post regularly useful. It helps to validate my efforts, which is critical
for motivation to continue. A couple days ago Mr. Dave Jones (N1UAV), sent
me a note about the stacked television antenna project he undertook after finding
the "How to Stack
TV Antennas to Increase Signal Strength and to Reduce Ghosts" article from the
November 1965 issue of Popular Electronics magazine. His location about
90 miles outside of Nashville, TN, is a challenge for trying to receive a good signal
from a television station from both an attenuation and multipath signal degradation
perspective. Dave began with a single antenna, but was not happy with the performance.
The results of adding the second antenna is amazing ...
Sometime around 1980, while stationed at
Robins AFB, Georgia, I finally succumbed to the peer pressure of other more sophisticated
audiophiles in the barracks and bought a "real" stereo. Unlike my roommate who had
a full compliment of rack-mounted gear, my meager enlisted military pay only allowed
for a mid-grade instrument. The solution was a
TA−300 Integrated Tuner Amplifier. It put out a whopping 30 watts per channel,
but unlike my existing radio (a Readers Digest 800−XR), those 30 watts were nearly
distortion free when driving good speakers. Having only the pathetic 5 W speakers
that came with the 800-XR, I designed a set of speakers rated for 60 W, and
built the enclosures myself in the base woodshop. Unfortunately, in preparation
for a household move about 20 years ago, I sold the Sansui and the speakers ...
As you already know if you are planning
to be at the International Microwave Symposium (IMS) this year, it is being held
from June 2nd through the 7th in Boston, Massachusetts. The last time the IMS show
was in Boston venue was 2009, and RF Cafe was there. It was my very first IMS show.
The entire day was spent taking photographs and meeting as many RF Cafe website
advertisers as possible. I also got to visit with a few people from companies I
used to work for. The National Electronics Museum had a very nice display set up
showcasing the evolution of the Microwave industry. Up until a couple weeks ago,
Melanie and were planning on returning this year to the IMS show, but some family
matters have required some extensive travel lately ...
Knowing that I am an avid consumer of literature
pertaining to time and astronomy, Melanie picked up a book at the library for me
Longitude: The True Story of a Lone Genius Who Solved the Greatest
Scientific Problem of His Time, by Dava Sobel. When Christopher Columbus
discovered America, his intended target was, if you recall, the Indies. His original
charter was to find a direct westerly pathway from the Atlantic coast of Europe
to the immensely profitable trade production region of the Indies as an alternative
to to sailing around the treacherous Cape of Good Hope at the southern tip of Africa.
How could such an experienced navigator have missed his mark by so far, you might
reasonably ask? Didn't Columbus know how to use a sextant, or at least have a navigator
who could? The answer to the second question is, "no." The answer to the first question
is complicated ...
Just about everyone who has worked in the
radar field for a long time is familiar with the name of
Dr. Robert M. Page. He was the first to come up with
the concept of monopulse radar, and he invented the familiar Plan Position Indicator
(PPI) radar display and the RF duplexer which allows one antenna to be connected
to both the transmitter and the receiver. Amazingly, I recently received an e-mail
from Dr. Page's son, John Page. An interest in his father's career combined
with insight that only growing up under the loving care of Dr. Page can provide
has afforded him some unique tidbits of information that many (most, per John) historical
accountings omit. Rather than me summarizing his letter, you will want to read it
yourself as presented below. World War II aficionados will particularly appreciate
the information. John pays homage to his father's co-workers ...
If you were around here in 2014, you might
recall my publishing a paper titled, "Drone-Based
Field Measurement System™ (dB-FMS)™." Since then, I have seen a few companies
doing this (here,
here, here, and many more); others are
coming online all the time. Those people have actually implemented working systems
that seem to perform very well. I'm not saying they got the idea from my article
because more than one person can have a brilliant idea ;-). It's just good to know
that my idea had some merit in the real world ...
February 11, 2019
Hello. My name is Kirt, and I'm a
vintage wired and wireless communications publication addict.
This affliction has had a hold on me for going on two decades now. Call it my middle
age crisis. At sixty years old, there is no sign of abatement in enthusiasm. Nearly
every day I still find myself reading and commenting on articles and advertisements
from mid-last-century magazines, newspapers, and catalogs. Maybe I'm hopeless and
will never be able to kick the habit. I'm not alone, though, based on some of the
feedback received from RF Cafe visitors. for that reason and others, maybe, in truth,
I've grown comfortable with my addiction. While perusing a few vintage newspaper
editions from the World War II era looking for relevant stories, I ran across
this November 1, 1940 (exactly 78 years ago) special section in the Harrisburg
Telegraph titled, "Radio Industry Marks 20th Anniversary." It contains many
November 1, 2018
It is probably safe to say that most people,
especially today, believe that the United States was suddenly and unexpectedly thrust
into involvement in
World War II on December 7, 1941, when the Japanese navy
launched a surprise attack on Pearl Harbor. The fact is the U.S. was "unofficially"
engaged for over a year beforehand by "lending" both equipment and personnel to
British, Russian, Chinese, French, and other militaries as part of their effort
to drive back invading German, Italian, and Japanese Axis forces. World War II
actually began in the Fall of1939 with Hitler's invasion of Poland. Americans, being
safely separated from the front lines by the Seven Seas, knew little of and were
concerned little about the goings on "Over There." Once the call to arms was sounded
with the Pearl Harbor attack, the country quickly and enthusiastically converted
to full wartime mode. Manufacturing plants ...
In all my years of repairing and restoring
old radios, I have never had the occasion to re-string a
dial cord. There are many variations on dial cord construction
and diameter, but there are even more variations in that way the path around the
tuning shaft, tuning elements, and indicator dials are implemented. Larger radios
with lots of room in them are relatively easy to re-string and usually take a fairly
straightforward path, but smaller portable multiband radios like my 1970's-vintage
Realistic Patrolman−50 are a bit of a challenge, as I found out
recently. A Web search on recommendations for how to replace dial cords results
mostly in frustrated handymen who have seemingly given up on the job. It is easy
to understand why, especially on a ridiculously complicated routing scheme. My only
guess as to the need for the multiple pulleys and specific number of wraps around
each is because of the need to maintain very solid contact while tuning four separate
variable capacitors ...
Late in 2016, news outlets began reporting
on American and Canadian diplomats stationed at their respective embassies in Cuba
complaining of dizziness, nausea, headaches, ringing in the ears, and other seemingly
sound-related illnesses. Similar reports have come out of China as well. At the
time, doctors and scientists investigating the phenomenon thought maybe some sort
of weaponized sonic beam was being directed at the personnel. Certain
people were affected while others nearby experienced no such phenomena, leading
researchers to believe that the presumably sonic beams were highly concentrated
and directional. Some of the targeted personal were diagnosed as having suffered
mild traumatic brain injury with likely damage to the central nervous system ...
In 2010, I posted a short piece about where
to look on the Web to learn what upper management, board members, and large investors
were doing with
insider company stock trades. At the time, the MSN Money website
had a tool where you could enter a company's stock symbol and get a readout of who
was buying and - more often that not - selling stock. That web page is gone, but
I found the same information on InsiderCow.com. The dollar amounts are truly staggering
to people like you (likely) and me (definitely). Numbers reported are sale values,
not profit to the stock holder. Many of the stocks were issued as either grants
or options, but even outright purchased stocks are included as well. Regardless,
prepare to have your jaw drop if you have never seen this type of data before. Some
of the more familiar technology companies have been selected for examples ...
While not quite the equivalent of an Elvis
sighting, I was utterly surprised to see an open
Radio Shack store in the Ashtabula Towne Square Mall during a
recent trip to Ohio. As you can see in the photo, it is a shell of a store, with
products on display only along the walls. Do you remember the days when every shopping
mall and plaza had a Radio Shack crammed full of stereos, radios, calculators, antennas,
computer accessories (and the TRS-80), toys, and of course a huge portion of the
store dedicated to electronic project components? I had a "Battery Club" card for
a couple decades, and a current catalog was always on my bookshelf. If, as the old
saying goes, "Misery loves company," then the good folks at the Ashtabula Radio
Shack can at least take some solace ...
Old Farmer's Almanac (OFA) has been on my annual need-to-buy list
for as long as I can remember. It is chock full of useful data for sunrise and sunset
times*, high and low tide times, crop planting days, first and last frost days,
and significant astronomical events. There are stories of interest on topics ranging
from canning your garden's harvest to how to view a solar eclipse. - often from
noted authors, but also from lay people. I also enjoy the monthly "on this day"
type tidbits and the homey short story relating to the time of year. After 225 years
of continuous publication, it still features the hole in the upper left corner to
facilitate handily hanging it on the wall of your shed -- or outhouse. I gave a
1961 edition of the Old Farmer's Almanac found on eBay to Melanie as a birthday
present this year ...
HP 5212A Electronic Counter was found in a second-hand shop
sitting in with a bunch of random electronic gear. The "HP" on the front panel piqued
my attention, so I carried it to the counter and asked the nice lady to plug it
in, figuring if the front panel lit up and none of the smoke that makes electronics
work leaked out, I'd buy it. It did, it didn't, and I did, respectively. The outside
condition is pretty good, with most of the scratches being on the top and bottom.
Some oxidation is present on the bare aluminum chassis components, but a little ...
If you grew up in the era of rooftop television
antennas, then there is a good chance you are familiar with the electromechanical
antenna pointing systems that were often installed as well. Alliance, Channel Master,
Cornell Dubilier, Radio Shack, RCA, Winegard, and others made low cost, light-duty
rotators for television antennas. Ham radio antenna rotators were/are
more robust in order to handle higher weight and wind loads. Many television antennas
also cover the FM radio band (88-108 MHz), allowing them to do double duty.
Being an unapologetic technology renaissance man, I recently purchased (on eBay)
a vintage Alliance Model U−100 Tenna−Rotor that was unused in the original ...
The manned space program has unarguably provided
mankind with many new and innovative tools, medicines, electronics, materials, physics,
materials, appliances, and mathematics. Know officially as "spinoffs," products
like the portable heart defibrillator unit, the portable vacuum cleaner, freeze-drying
food processors, powdered lubricants, memory foam, quartz clocks and battery-powered
NASA inventions have not found an application in your basement
or garage, however, because their purpose is too specialized. Take, for instance,
the ZeRT, or Zero Reaction Tool ...
You might have noticed that since last November
the engineering and science themed daily RF Cafe header images have been much larger
than those which graced the pages in the past. The change was motivated mainly by
a desire to make them more viewable on the tiny screens of mobile phones. It also
gave me the opportunity to include more information. In the process, I took the
occasion of being on each daily
engineering and technology history page to check on the validity
of the long ago included hyperlinks to pages which validated dates of events. Use
Wikipedia was avoided because of the joke-worthy reputation it had for bogus ...
To be or not to be - that is the question:
Whether 'tis nobler in the mind to suffer the slings and arrows of outrageous bi-annual
clock shifts, or to take up arms against a sea of contradicting justifications for
and against its existence for DST, and by opposing, end it. Twice each year, a majority
of the western world is subject to a manmade disruption in circadian and habitual
cycles with an inane one-hour clock change on and off of "Daylight Saving(s) Time" (DST). Some historians claim that Benjamin
Franklin joked about DST in the 18th century, but it was New Zealander George Hudson
who proposed the modern day clock ...
Have you ever started a relatively simple
investigation into a trivial matter, only to find yourself going down the metaphorical
"rabbit hole" even after finding the original answer? Such was the case for me when
someone sent me an e-mail with a signature that included his
amateur radio call sign. The first three characters, KB3, matched
mine and that got me wondering on what date his call sign was granted compared to
mine. Let us say for example* the writer's call sign was KB3PGM and mine is (actually)
KB3UON. I looked them up in the FCC's ULS self-serve license ...
If, as the saying goes, "Misery loves company,"
then you will appreciate the following. Whilst perusing the December 2017 issue
of NASA's Motion Design supplement to their Tech Briefs publication,
I ran across the image to the right in an article titled, "Trends in Hydraulic Filtration"
(areas of interest are quite diverse here at RF Cafe).
After reading the caption stating that the holes were "fire holes," the first thing
that came to mind was
ESD damage. Sure enough, upon going back and reading more of the
story (provided by Argo-Hytos), I found ...
Another era, sadly, has come to an end. H. Ward
Silver (aka Ward Silver, NØAX) has announced the end
of his monthly column, "Hands-On Radio," in QST magazine. The title of each column
was enumerated as "Experiment #nnn," followed by the subject. To wit, "Experiment
#179 Maxwell's Equations - The Wave Emerges" is Mr. Silver's final column,
appearing in the December 2017 QST. "Hands-On Radio" topics ranged in intensity
from relatively simple discussion on calculating power dissipation in resistors,
capacitors, and inductors to more heady treatises on subjects like electromagnetic
fields within coaxial cable and waveguide to Maxwell's equations. Mathematics, too ...
One of my favorite old-time
radio personalities, Paul Harvey, had a trademarked feature titled The Rest of the
Story. For those of you not familiar with the format, Mr. Harvey would begin his
story talking about particular life aspects of a person that, while remarkable,
usually had no connection with the person's eventual claim to fame. The listener's
challenge was to guess who the person was before it was revealed at the very end,
followed by, "... now you know --- the rest [emphasis] of the story." As far as
I know the story of FM radio inventor
Armstrong was never a subject, although it certainly met the criterion. I've
already let the figurative cat out of the bag, so you already know my subject ...
From May 9th through the 11th in the year
of our Lord 1958, the very first "Jamboree
on the Air" (JOTA) was held by the Boy Scouts of America (BSA). The American
Radio Relay League (ARRL), in conjunction with the BSA, is promoting this year's
60th anniversary event occurring from October 20-22. As you might imagine, quite
a lot has changed over 59 years in terms of equipment, but the basics in terms of
encouraging and assisting the next generation of licensed Hams remains as always
the primary goal of organizers. The Boy Scouts, of course, join in for the fun and
learning experience. Jamboree on the Air events, held in October, do not coincide
with the National Scout Jamboree, held in July ...
Nikola Tesla was born in 1856 in Smiljan,
Austrian Empire, and died in 1943 in New York City. His life is so amply documented
far and wide that regurgitating the information in books and blog posts would be
a waste. Most of what you find there is second-hand, having gone through the filter
of an author's preferences. I like to search for stories on various topics in their
original publications; e.g., scanned newspaper and magazine archives. A hunt for
early stories on Nikola Tesla turned up many 19th century examples from the Newspapers.com
website. It is interesting that back in the day, men like Nikola and Edison were
referred regularly to as "electricians." The oldest article I found on Nikola Tesla
appeared in the July 1, 1889 edition of The Pittsburgh Dispatch, titled "The
Electric Fiend" ...
It's finally here - the
Great North American Solar Eclipse of 2017! The amateur astronomy
community has been anticipating and preparing for the event for a couple years.
Astronomy magazine dedicated the entire August issue to providing detailed
information on viewing suggestions along the entire path. Traffic from the Pacific
Coast of Oregon to the Atlantic Coast of South Carolina will probably be a challenge
as people vie for positions as close to the centerline as possible. Those who manage
optimal locations will see about 2 minutes and 40 seconds of total darkness. Others
within the 68-mile-wide path of totality will see from a fraction of a second up
to the full extent. According to a calculator on the Vox website, we will only see
a 76.2% eclipse, which will barely darken our skies ...
Hmmm.... let us see what made the front page
of the July 1, 1948 edition of Murray Hill, New Jersey's, The Madison Eagle newspaper:
"Man Found Dead, Wedged in Drain on Park Edge," "Lawyer Fined $50 on Zone Charge,"
and Sandra Dean Stevenson had been born two weeks earlier. Oh, also included was
"Invention Replaces Vacuum Tube" and "Local Man Invents New Device
in Electronics for Bell Lab; Could Revolutionize Radio." Page 10 ran, "Bell Laboratory
Releases Data on Newly Invented Transistor." It is widely known that Drs. Brattain,
Shockley, and Bardeen formerly announced on December 23, 1947, within the walls
of Bell Labs ...
We have all been treated to a seemingly endless
series of headlines portending rising ocean levels and the ensuing drowning of costal
cities due to
melting ice in the polar regions. This phenomenon ostensibly is
brought on by the exponential increase in carbon emissions from developing third-world
countries as well as established first-world countries in the post World War II
era ... or was it post Vietnam, or maybe post Gulf War? The reference keeps changing,
but it definitely began occurring since at least 1990, right? There is a problem,
though. In the early and mid 1970s climate scientists began warning us of an approaching ...
For some inexplicable reason, it seems that
of the many articles I read dealing with antenna and feedline efficiencies, rarely
receive side of the equation addressed. Yes, transmit power is
expensive and there is a legitimate reason to reduce losses when converting power
amplifier output to in-the-air power, especially for DX operations. However, it
doesn't do much good to launch the full permissible 1,500 watts PEP and make a contact
on the other side of the world if your system cannot receive a reply because of
the excessive line loss and/or mismatch loss between your antenna and your receiver.
Antennas and feedlines are reciprocal elements so if ...
Friends, former employees, and fellow lovers
of all things electronic, we are gathered here today to remember and honor our lifelong
friend and enabler of our hobby and passion,
Radio Shack - once a Tandy company, as we are familiar with it.
Radio Shack has lingered in failing health for a decade, all the time keeping a
brave face on its dwindling number of stores. Caretakers attempted a variety of
infusions and transplants in an attempt to save the American stalwart electronics
retailer. Alas, a confluence of poor management ...
For Mother's Day this year, the kids and I
got Melanie a 23andMe DNA testing kit. She has spent a fair amount of time over
the years researching the family lineage which, in case you care, traces back primarily
to Germany and Switzerland. Along with some of the online ancestry websites, she
searched the U.S. Census database for immigration and early American household information
(number of people, ages, names, occupations, etc.) The entire
1930 Census form consisted of a single page seeking basic information
on whether you own or rent, value of the home, live on a farm or not, color or race, ...
Long-time RF Cafe visitor and occasional
contributor Gary Steinhour, KF6U, recently sent me a note saying he had acquired
a very used
Heathkit DX-60B amateur radio transmitter and was in the process
of restoring it. Gary's first transmitter as a freshly minted Ham over 50 years
ago was a DX-60, so this was an effort to satisfy a nostalgic emotional attachment.
The project is complete now, and boy does it look nice! Gary provides a brief account
If you have ever seen the result of a lightning
strike on electronic equipment, then you know how devastating it can be - often
total destruction that includes molten metal. Woe be unto any human operator who
happens to be in contact with it at the time of the strike. Unprotected antennas
are begging for contact. Shortly after leaving a company where I worked on a Tx/Rx
system for a phased array weather radar I got word that the indoor equipment rack
took a major hit because the guy who maintained the site forgot to reconnect a
lightning rod system cable after moving it during ...
Miscellaneous Earlier Smorgasbords and Factoids: