See Page 1 |
2 |
3 |
4 | of the May 2023 homepage archives. Sunday the 14th
 This custom RF Cafe
electronics-themed crossword puzzle for May 14th contains words and clues which
pertain exclusively to the subjects of electronics, science, physics, mechanics,
engineering, power distribution, astronomy, chemistry, etc. If you do see names
of people or places, they are intimately related to the aforementioned areas of
study. Being that "N" is the 7th letter of the alphabet, it is used as the first
and/or last letter of many words in today's crossword puzzle. As always, you will
find no references to numbnut movie stars or fashion designers. Need more crossword
RF Cafe puzzles? A list at the bottom of the page links to hundreds of them dating
back to the year 2000. Enjoy.
 The RFCafe.com website exists partly on the support
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 KR Electronics has been designing and manufacturing
custom filters for military and commercial radio, radar, medical, and communications
since 1973. KR Electronics' line of filters includes lowpass, highpass, bandpass,
bandstop, equalizer, duplexer, diplexer, and individually synthesized filters for
special applications - both commercial and military. State of the art computer synthesis,
analysis and test methods are used to meet the most challenging specifications.
All common connector types and package form factors are available. Please visit
their website today to see how they might be of assistance. Products are designed
and manufactured in the USA.
Friday the 12th
 A while back, I posted the "Battery Types
and Their Characteristics" article from the April 1973 issue of Popular Electronics
magazine. While preparing it I ran across Eric Wrobble's vintage battery collection.
All of the battery types shown in the lead photo of this 1963 Radio−Electronics
"Inside
the Dry Cell" article can be found amongst them. Back in the day, energy storage
density was low compared to the chemistries employed in modern cells. Nickel cadmium
(NiCad) dominated the rechargeable battery market for dry cell types. Lead-acid
cells did and still do pack a lot of energy into a given volume of space, but they
are very heavy and can be potentially destructive if the electrolyte finds it way
outside the shell. In the early days of radio controlled model airplanes, wet cells
were often used for powering the airborne electronics, and many otherwise survivable
crashes resulted in loss of the model because acid leaked from a crack in the battery
pack. Today, lithium polymer (LiPo) and lithium ion (Li-Ion) cells and battery packs
rule the portable electrical device world. They pack an enormous amount of energy
into a volume, recharge quickly, and are very safe...
 OK, I give up. What is a "pukka
amateur?" According to an online dictionary: pukka, adj (esp in India) 1. properly
or perfectly done, constructed, etc. a pukka road 2. genuine pukka sahib. Then,
we have a Blattnerphone. That sounds an awful lot like Blattenberger, or maybe more
like Blattnerberger. Anyway, a Blattnerphone was an early attempt at recording sound
on a steel tape - never heard of it before now. My native language is English, but
evidently there are still a lot good words to learn which have been forgotten by
society over the years. If you read enough vintage magazines from the first half
of the 20th century, you will run across many words and phrases that are still in
the Merriam-Webster dictionary, but you hardly ever see or hear them used anymore.
These are some great candidate words for Scrabble...
 Exodus Advanced Communications is a multinational
RF communication equipment and engineering service company serving both commercial
and government entities and their affiliates worldwide. Power amplifiers ranging
from 10 kHz to 51 GHz with various output power levels and noise figure
ranges, we fully support custom designs and manufacturing requirements for both
small and large volume levels. decades of combined experience in the RF field for
numerous applications including military jamming, communications, radar, EMI/EMC
and various commercial projects with all designing and manufacturing of our HPA,
MPA, and LNA products in-house.
 "There was a time, not too long ago, when
hardware design was the pinnacle of the technological world. While hardware startups
used to be abundant and advisable to start, it now feels like
hardware has fallen out of favor in the venture-capital world. The software
industry now enjoys the palpable excitement that used to exist around hardware -
and rightfully so. Compared with software startups, hardware startups have become
much more expensive, time-consuming and riskier to build. Software isn't inherently
easy or cheap to build. Still, the software industry has experienced tremendous
growth over the last 20 years. A large part of this is the abundance of modern tools
that have been developed to support software developers as the field grows. When
you look at the electronics engineering industry, however, you find that the tools
are antiquated and lacking. Where are these modern and powerful tools for the hardware
space? At Flux, we are determined to fix the broken hardware design paradigm..."
 Television interference (TVI) was a major
concern for amateur radio operators back in the heyday of broadcast TV. Other than
radio broadcasts, magazines, and newspapers, it was the only other major form of
media available; there was no Internet. Even the lowest priced TV sets represented
a significant portion of a typical family's disposable income. There was no government
handout program that provided every household with a television set and antenna.
Consequently, people were very irritated by nearby electrical or electronic equipment
that dared to interfere with their reception - and rightly so. Ham radio operators
broadcast on bands that were fairly well separate from the TV channel frequencies;
however, harmonics and intermodulation products often fell in the TV bands, and
that caused real problems with the public perception of amateur radio. Articles
like this were aimed at helping people tame the TVI and make peace with their neighbors...
The RFCafe.com website exists partly on the support
of its visitors by way of a small percentage earned with your
Amazon.com purchases, which typically works out to less than
$20 per month. That does not even cover the domain registration and secure server
fees for RFCafe.com. If you plan to buy items via
Amazon.com, please click on this link to begin your shopping
session from here so that I get credit for it. Doing so does not cost you anything
extra. Thank you for your support.
 Since 1996, ISOTEC has designed, developed
and manufactured an extensive line of RF/microwave connectors, between-series adapters, RF components
and filters for wireless service providers including non-magnetic connectors for
quantum computing and MRI equipments etc. ISOTEC's product line includes low-PIM
RF connectors components such as power dividers and directional couplers. Off-the-shelf
and customized products up to 40 GHz and our low-PIM products can meet -160 dBc
with 2 tones and 20 W test. Quick prototyping, advanced in-house testing and
high-performance. Designs that are cost effective practical and repeatable.
Thursday the 11th
 Time to put on your thinking caps once again.
No person is credited for these three "What's
Your EQ?" challenges from the March 1963 issues of Radio−Electronics
magazine. In other instances (see below) it is E. D. Clark. BTW, EQ stands for Electronics
Quotient. My solution for the "Four−Bulb Puzzler" was different from the one proposed.
Given that semiconductor diodes were available at the time, I put a 6.2−V zener
diode (a common value at the time) across each bulb, figuring if the bulb burnt
out (open-circuited), the zener would drop the voltage normally dropped by the 6 V
bulb. While the bulb is operating, the voltage across the zener would not turn it
on. Of course there could be a problem with the current through the diode being
too high when turned on, without a limiting resistor. "Simple Circuit?" would take
more time than I am willing to expend right now. With "Ohms, Sweet Ohms" don't let
the wording of the proposition bias (pun intended) your analysis...
 Somehow the existence of "C-Q Serenade" managed to
evade my attention. I think it recently appeared in the ARRL's QST magazine, but
not certain that is where I saw it. The song opens with a Swing era tone with the
lady singing, "dah-di-dah-dit dah-dah-di-dah." Per the YouTube page, "This
private label record was pressed in souvenir of the May 7th, 1960 Dayton Hamvention.
Vocals are by Joyce Hahn. This song apparently covers an earlier French Quebec version
I'd love to find. In fact, there is a CT "Track number", CT-26815, just like most
French and a few other English Canadian songs recorded through the 60s and early
70s. The record itself has no catalog number." Check out
Morse Code in the "Western
Union" song (and others)...
 "The
Dartmouth Summer Research
Project on Artificial Intelligence, held from 18 June through 17 August of 1956,
is widely considered the event that kicked off AI as a research discipline. Organized
by John McCarthy, Marvin Minsky, Claude Shannon, and Nathaniel Rochester, it brought
together a few dozen of the leading thinkers in AI, computer science, and information
theory to map out future paths for investigation. A group photo [shown above] captured
seven of the main participants. When the photo was reprinted in Eliza Strickland’s
October 2021 article 'The Turbulent Past and Uncertain Future of Artificial Intelligence'
in IEEE Spectrum, the caption identified six people, plus one 'unknown.' So who
was this unknown person? Who is in the photo? Six of the people in the photo are
easy to identify. In the back row, from left to right, we see Oliver Selfridge,
Nathaniel Rochester, Marvin Minsky, and John McCarthy. Sitting in front on the left
is Ray Solomonoff, and on the right, Claude Shannon. All six contributed to AI,
computer science, or related fields in the decades..."
 The "BS" part of
this device's name must refer to the FAA's outrageous requirement that R/C hobbyists
carry identification devices aboard every model - not just drones but even
gliders
and power planes. The $89 (+ tax and shipping) price tag is a far cry from the FAA's
promise of "inexpensive" devices. This is yet another unnecessary tax upon citizens.
"Dronetag has announced their 'Dronetag BS' system as a cost-effective method to
bring consumer UAVs into Remote ID compliance. Dronetag BS is, of course, short
for 'Dronetag Basic Solution,' though
the company is sure to draw in some eyes with their brash take on the normally staid
UAV market. The firm will offer Dronetag BS for an
introductory price of $49 upon its
May 22 drop date, offering the special for the first 24
hours of its release. For those that miss the intro rate, the standard retail price
will remain at $89. The firm obviously has its feet in the trenches with the average
drone pilot, admitting that many don’t quite think much positive regarding the new
Remote ID regulations.
The Dronetag BS allows operators to easily bring their small aircraft into compliance
with a compact..."
 OK, class, put your books away and take
out a pencil. Spread your chairs out because we're going to have a short test today.
A collective sigh permeates the room. Remember those days? I still have nightmares
over those moments, and they were decades ago for me. At least this "Electronic
Noise Quiz" from the August 1962 edition of Popular Electronics magazine
won't affect your GPA. Sometimes PE's quiz illustrations are kind of hard to interpret,
but this one does a pretty good job (except item "E," but I'm not telling what it
is since nobody helped me). You will need a fairly diverse background in consumer
type electronics to do well, and having a few gray hairs, like me, will probably
help ;-) Good luck. BTW, my score was a somewhat embarrassing 80%...
 With more than 1000
custom-built symbols, this has got to be the most comprehensive set of
Visio Symbols available for RF, analog, and digital system and schematic
drawings! Every object has been built to fit proportionally on the provided
A-, B- and C-size drawing page templates (or can use your own). Symbols are provided
for equipment racks and test equipment, system block diagrams, conceptual drawings,
and schematics. Unlike previous versions, these are NOT Stencils, but instead are
all contained on tabbed pages within a single Visio document. That puts everything
in front of you in its full glory. Just copy and paste what you need on your drawing.
The file format is XML so everything plays nicely with Visio 2013 and later...
 TotalTemp Technologies has more than 40
years of combined experience providing thermal platforms.
Thermal Platforms
are available to provide temperatures between −100°C and +200°C for cryogenic cooling,
recirculating & circulating coolers, temperature chambers and temperature controllers,
thermal range safety controllers, space simulation chambers, hybrid benchtop chambers,
custom systems and platforms. Manual and automated configurations for laboratory
and production environments. Please contact TotalTemp Technologies today to learn
how they can help your project.
Wednesday the 10th
 While not a precise method of determining
the input and/or output impedance of black box type devices, the described voltage
division method suffices for many - if not most - situations. The June 1969 issue
of Popular Electronics magazine offered this process of placing a variable
resistance (potentiometer) at the device under test (DUT) input and/or output and
adjusting the voltage reading to be half the value without the resistor. When both
the source and the load are pure resistance (no capacitance or inductance), it is
safe to assume the after-adjustment value of the resistor represents the DUT impedances
- that is only a real part and no imaginary part (Z = R ± j0 Ω). The precise method
of determining the impedances requires a little extra work. Rather than describe
it here, I refer you to a very nice c2008 paper by Mr. Kenneth A. Kuhn entitled,
"A Simple Circuit for Measuring Complex Impedance."
 Imagine what this pristine land would look
like with a major evacuation and processing operation. Oh, wait, that's only bad
for U.S. locations. "In June 2022, six Boeing 737s - fully loaded with tents, food,
satellite Internet equipment, drones, geophysical survey gear, drilling equipment,
and a team of experienced geologists - flew to a remote airstrip in northern Quebec.
The geologists were hunting for major
deposits of the minerals needed to power a clean-energy future. Given the mix
of cutting-edge scientific computing and old-school bravado, it was as though they
were channeling Alan Turing and Indiana Jones simultaneously. Our startup, KoBold
Metals, acquired an 800-square-kilometer mineral claim in the region based in part
on predictions from our artificial intelligence systems. According to the AI, there
was good reason to believe we'd find valuable deposits of nickel and cobalt buried
below the surface. Summer snowmelts in this near-arctic region created a brief window
to bring in a small village's worth of equipment and personnel to test our predictions.
We cofounded KoBold in 2018 with backing from Bill Gates's Breakthrough Energy Ventures
and Silicon Valley venture capital firm Andreessen Horowitz..."
 Most people today under 30 years old have
probably never seen the mechanics or electronics inside their many personal devices.
Everything is so miniaturized and optimized that if something does go wrong, there
is little chance of the owner repairing it. Instead, the phone, television, stereo,
microwave oven, whatever, gets thrown away and a relatively cheap (compared to paying
for a repair) replacement is purchased (or stolen). Besides, if the item was more
than two years old, it was on the verge of obsolescence anyway. Up until around
the early to mid 1980s you had a fair chance of being able to repair an electronic
circuit if trouble arose because at least with commercial products
printed circuit boards (PCBs) were usually 1- or 2-sided and the components
still had leads protruding from the sides of the packages. A $10 Radio Shack soldering
iron and some solder wick was sufficient to remove and replace just about any failed
component. Home brew PCBs could be made to nearly the same quality as commercial
versions using a resist ink pen (basically a Magic Marker) and a dish of ferric
chloride etchant liquid. A drill press helped with making holes for the component
leads, but a hand drill would get the job done. No more, though. If you are resourceful
enough to get your cellphone...
 Withwave is a leading designer and developer
of a broad range of RF, microwave, and millimeter−wave test solutions and subsystems
with a focus on electromagnetic field analysis and signal processing. Withwave's
new line of
Vertical Launch Connectors are specially designed for solderless vertical PCB
launch on test & measurement boards. These connectors have excellent electrical
transition performance up to 26.5 GHz (SMA), 40 GHz (2.92 mm), 50 GHz
(2.4 mm), 67 GHz (1.85 mm), and 110 GHz (1.0 mm), in both male and female
configurations, and reduce installation time by eliminating soldering. Low VSWR
on properly designed substrate. Applications include test and measurement, high
speed digital test boards, and characterization boards. 3D models for mechanical
layout (STEP file), and ANSYS HFSS models for 3D electromagnetic simulation are
available...
 Often times in technical literature, the
phrase "Lorem Ipsum" appears as a generic filler for titles, names, and other nouns.
Microsoft user's guides, back when such items were printed, used
Lorem Ipsum
extensively, as did the Aldus (now Adobe) PageMaker. In fact, Lorem Ipsum has been
used as a standard for text layout since the 1500s. The variation of character widths
and "p" with a descender provided typesetters with a means to estimate the space
needed to print a typical page, and the phrase, being in a foreign language, does
not unnecessarily take the reader's focus off the main point of the article. Latin
seems to be a good "neutral" language to use for printed matter that would ultimately
be translated into multiple other languages. One problem though: Lorem Ipsum is
not Latin. In fact, Lorem Ipsum is really based on no language at all, but is adopted
from a passage in Latin by Cicero, in 45 BC: "Neque porro quisquam est qui dolorem
ipsum quia dolor sit amet, consectetur, adipisci velit...," which translated, is,
"There is no one who loves pain itself, who seeks after it and wants to have it,
simply because it is pain..." Lorem Ipsum has become a noun...
 With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Visio Stencils available for RF, analog, and digital system and schematic
drawings! Every stencil symbol has been built to fit proportionally on the included
A-, B-, and C-size drawing page templates (or use your own page if preferred). Components
are provided for system block diagrams, conceptual drawings, schematics, test equipment,
racks (EIA 19", ETSI 21"), and more. Test equipment and racks are built at a 1:1
scale so that measurements can be made directly using Visio built-in dimensioning
objects. Page templates are provided with a preset scale (changeable) for a good
presentation that can incorporate all provided symbols...
 Innovative Power Products has been designing
and manufacturing RF and Microwave passive components since 2005. We use the latest
design tools available to build our baluns, 90-degree couplers, directional couplers,
combiners/dividers, single-ended transformers, resistors, terminations, and custom
products. Applications in military, medical, industrial, and commercial markets
are serviced around the world. Products listed on the website link to detailed mechanical
drawings, electrical specifications, and performance data. If you cannot find a
product that meets your requirements on our website, contact us to speak with one
of our experienced design engineers about your project.
Tuesday the 9th
 Since first beginning in 1946, Howard W. Sams
PhotoFacts were the de facto standard for technical documentation on radio, television,
phonograph, magnetic tape machines, and other forms of electronic entertainment.
Other companies such as
Colorgrams, a division of TV Development Corporation, introduced competitive
products which appear to be of high quality, but Sams' documentation packages ruled
the repair shop roost. A sample of a TV Colorgram datasheet can be seen in this
two-page spread in a 1963 issue of Radio−Electronics magazine. A few Colorgrams
packages can be found occasionally on eBay, but the number pales in comparison to
Sams FotoFacts. Although nowhere near as comprehensive as the commercially published
documentation packages, the electronics trade magazines often published at least
schematics and parts lists of various products. At the time, manufacturers only
made that information available to authorized dealers and service shops...
 "From access cards and key fobs to Bluetooth
speakers, the security of communication between wireless devices is critical to
maintaining privacy and preventing theft. Unfortunately, these tools are not foolproof
and information on how to hack, clone and bypass these systems is becoming easier
to find. That's why computer engineers at the University of Illinois Chicago have
been investigating ways to create more secure devices. In a new paper, UIC scientists
report a method inspired by quantum physics to improve wireless device identification
and protect device-to-device communication. It uses a truly random and unique digital
fingerprint to create a hardware encryption system that is virtually unbreakable.
The scientists, led by Pai-Yen Chen, used a theory from quantum physics in math-based
experiments to identify a
divergent exceptional point. Quantum physics describes systems for which precise
measurement is difficult or impossible; a quantum state describes a parameter space
or range of possible measurements. Within these states, there exist exceptional
points where the uncertainty of the system is at its maximum..."
![Electronic Warfare and Radar Systems Engineering Handbook - Jamming-to-Signal Ratio (J/S) - Constant Power [Saturated] Jamming - RF Cafe](images/ew-electronics-handbook-jamming-signal-ratio-hp.gif) This section derives the
Jamming-to-Signal (J/S) ratio from the one-way range equation for J and the
two-way range equation for S, and deals exclusively with active (transmitting) ECM
devices or systems. Furthermore, the only purpose of the ECM considered is to prevent,
delay, or confuse the radar processing of target information. By official definition,
ECM can be either Jamming or Deception. This may be somewhat confusing because almost
any type of active ECM is commonly called "jamming", and the calculations of ECM
signal in the radar compared to the target signal in the radar commonly refer to
the "jamming-to-signal" ratio. Therefore this section uses the common jargon and
the term "jammer" refers to any ECM transmitter, and the term "jamming" refers to
any ECM transmission, whether Deception or Concealment. Jamming: "Official" jamming
should more aptly be called Concealment or Masking. Essentially, Concealment uses
ECM to swamp the radar receiver and hide the targets. Concealment (Jamming) usually
uses some form of noise as the transmitted ECM signal...
 Teledyne e2v HiRel, a leading provider of
high−reliability semiconductor solutions, is proud to announce the release of a
new space COTS (Commercial-off-the-Shelf) phase locked loop (PLL) designed to deliver
exceptional performance and reliability in space applications. The
TDPL97240 is packaged in a small, 7x7 mm, non−hermetic, epoxy sealed, ceramic
quad, no−leads, (QFN) flat package that offers 75% board size reduction vs. the
standard space grade ceramic part. It is radiation tolerant to 100 krad (Si)
total ionizing dose (TID) and built on silicon−on−sapphire (SOS) technology. This
gives the PLL natural radiation tolerance and immunity to single−event latch−up
(SEL) effects. It also has a lock frequency range of 50 MHz-5 GHz, dual
modulus prescaler (5/6 & 10/11) for greater frequency flexibility and capability
of either serial interface or direct pin programming. "We are thrilled to offer
our customers a cost−effective solution that delivers the high-reliability and high-performance
needed for space applications...
 J.K. Bach (not Johann [J.]S.) was amazingly
prescient in 1944 with the specific types of RF-based devices that would come to
be common place in our modern world. Dig this: "Radar
can even be applied to the home, as a burglar-alarm, for example, or to detect
obstructions on the cellar steps. Electronic devices will find many other uses as
high-frequency paint-dryers, veneer-gluers, and even cordless permanent-waving machines
for the ladies. Garage-door openers and other remote-control devices are not only
possible but practical. Then there are certain to be other applications such as
personal pedestrian telephones, two-way wrist-radios and nursery baby-cry announcing
systems." Nostradamus' divination record might not even be that good. His tongue-in-cheek
thesis of ubiquitous RF interference due to the presence of Ham radio operators
is not far off either, although the accused "menace" would have to be extended to
include all the many varied emissive devices...
 New Scheme rotates
all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000
website visits each weekday.
RF Cafe is a favorite
of engineers, technicians, hobbyists, and students all over the world. With more
than 17,000 pages in the Google search index, RF Cafe returns in favorable
positions on many types of key searches, both for text and images. New content is
added on a daily basis, which keeps the major search engines interested enough to
spider it multiple times each day. Items added on the homepage often can be found
in a Google search within a few hours of being posted. If you need your company news to be seen, RF Cafe is the
place to be.
 Windfreak Technologies designs, manufactures,
tests and sells high value USB powered and controlled radio frequency products
such as RF signal generators, RF synthesizers, RF power detectors, mixers, up /
downconverters. Since the conception of WFT, we have introduced products that have
been purchased by a wide range of customers, from hobbyists to education facilities
to government agencies. Worldwide customers include Europe, Australia, and Asia.
Please contact Windfreak today to learn how they might help you with your current
project.
Monday the 8th
 You can tell by the number of articles in
electronics magazines (see list at the bottom) that a lot of people struggled with
the concept of decibels (dB). Probably the issue was more
converting between linear units and decibel units, since exponents and logarithms
are involved. Teaching someone to add and subtract decibels, or to multiply and
divide, respectively, linear units is relatively simple, and is not confusing. For
some people, converting power levels from watts (or milliwatts) to decibels can
become a rote operation; no real understanding of the concepts is required, but
throw in a factor of two for voltage to power (and vice versa), and the eyeballs
are likely to roll back in the head ;-) Mr. Eric Leslie did his part to try
to ease the pain in this "The Useful Decibel" article in the February 1968 issue
of Radio−Electronics magazine...
 This just in from
The Kobeissi
Letter: "Total tech layoffs in 2023 officially cross 190,000, already
surpassing the 2022 total of 165,000. January marked the most tech layoffs in a
month since 2001, impacting 89,500 employees. Total tech layoffs since 2022 are
now at 355,000 employees from 1,700 companies. The number of layoffs accelerated
beginning in Nov. 2022. Over the last 7 months alone, total tech layoffs are now
at 255,000 employees. Most companies have cited cost cutting and economic uncertainty
as reasons behind the layoffs..."
 Mostly just old farts like me remember anything
about
LORAN (LOng RAnge Navigation). My familiarity with it came not from boat navigation,
but from airplane navigation. Before LORAN became totally obsolete due to GPS (phased
out in U.S. and Canada in 2010), the transmitter stations were commonly tuned in
in order to obtain positional fixes via triangulation. Whilst taking flying lessons
at Lee Airport, in Edgewater, Maryland, the ground instructor included it in the
lessons, and even the FAA Private Pilot exams had a question or two on LORAN. The
el cheapo Piper Colts that I flew were lucky to have a VOR (VHF omnidirectional
range ) receiver in it, so I never actually used LORAN. They did have direction
finders (DF), which could tune in, among other things, VHF television station channels
to get a bearing (but not distance) to the stations. This article touches on the
principles of both radar (radio detection and ranging) and LORAN. BTW, why do we
still capitalize all of the acronym "LORAN" but not "RADAR?" Variations of LORAN,
like Loran-C, are not fully capitalized. Just wondering...
 Triad RF Systems' products and services
will be on display at numerous industry events throughout the season. Please be
sure to stop by and visit our knowledgeable engineering and sales staff. We also
have major news regarding company partnerships, product announcements, and technical
resources. Triad RF Systems is excited to be returning to AUVSI in 2023, this time
with new RF integration advancements and the same quality products our company is
known for. With over a decade of delivering SWaP-sensitive and optimal output power
products, we have become the RF amplifier designer and manufacturer of choice for
many UAS customers from all over the world. We will be at the Small Satellite Show
in Utah on August 7−10...
 A portion of the tread pattern on the wheels
of NASA/JPL's Curiosity Mars rover consists of a series square and rectangular holes
that serve as "visual
odometry marks." They are arranged in an asymmetric pattern on the rover that
will leave an imprint on the surface of Mars so the onboard cameras can look at
them to determine whether the craft is actually traversing the distance it is being
commanded to move. Less distance between sets of marks are an indication that slippage
is occurring. If that happens and Curiosity cannot correct itself, it will stop
and make a call back home to JPL and await further instructions. The round-trip
call can take anywhere from about 6 minutes to more than 44 minutes depending on
the two planet's orbital positions, not including the time needed to formulate a
reply. Look more closely at those visual odometry marks, however, and you will notice
those holes are squares and rectangles that make up dots and dashes, respectively,
for Morse code. The succession of three rows spells out •−−− •−−• •−•• (JPL). Clever,
non? Just as aliens live among us largely undetected, so too do amateur radio operators.
Occasionally a breadcrumb is left behind that the keen observer will recognize...
RF Cascade Workbook is the next phase in the evolution of
RF Cafe's long-running series, RF Cascade Workbook. Chances are you have
never used a spreadsheet quite like this (click here for screen capture). It is a full-featured RF system
cascade parameter and frequency planner that includes filters and mixers for a mere
$45. Built in MS Excel, using RF Cascade Workbook 2018 is a cinch
and the format is entirely customizable. It is significantly easier and faster than
using a multi-thousand dollar simulator when a high level system analysis is all
that is needed. An intro video takes you through the main features...
 The leading website for the PCB industry.
PCB Directory is the largest directory of
Printed Circuit Board (PCB)
Manufacturers, Assembly houses, and Design Services on the Internet. We have listed
the leading printed circuit board manufacturers around the world and made them searchable
by their capabilities - Number of laminates used, Board thicknesses supported, Number
of layers supported, Types of substrates (FR-4, Rogers, flexible, rigid), Geographical
location (U.S., China), kinds of services (manufacturing, fabrication, assembly,
prototype), and more. Fast turn-around on quotations for PCB fabrication and assembly.
These archive pages are provided in order to make it easier for you to find items
that you remember seeing on the RF Cafe homepage. Of course probably the easiest
way to find anything on the website is to use the "Search
RF Cafe" box at the top of every page.
About RF Cafe.
Homepage Archive Pages
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