Homepage Archive - March 2024 (page 1)

See Page 1 | 2 | 3 | 4 | of the March 2024 homepage archives.

Thursday the 7th

News Briefs

News Briefs, March 1967 Radio-Electronics - RF CafeIn 1967 when this set of News Briefs was published in Radio−Electronics magazine, the use of semiconductors in laser light applications was the domain of government, corporate, and university research laboratories. The device only modulated the beam. It did not generate the beam, although as seen below infrared laser diodes were already in the works. Also wowing the readership was a pinhead-size gallium arsenide (GaAs) transmitter which could generate frequency modulated (FM) signals in the 60 MHz to 2.5 GHz range. The "highest ever" starting salary for engineering students in that year was a whopping $166/week, or $8,632/year. That is the equivalent of $80,674 in 2024 money. By comparison, $16/hour fast food workers in California are pulling in $33,280/year, and qualify for many welfare benefits and healthcare. A really interesting item is how a group of British high school radio enthusiasts routinely tracked Russian satellite orbits to reverse engineer the point of launch, and on occasion discovered new ground bases, like the Plesetsk Cosmodrome in Mirny.

Must We Have UHF-TV?

Must We Have UHF-TV?, May 1962 Popular Electronics - RF CafeWhen UHF broadcast television was being introduced, pundits - as pundits are wont to do - were quick to predict the rapid, imminent demise of VHF channels. To wit, "All current VHF stations (operating on channels 2 through 13) may be scrapped, and operations shifted to the UHF band." That was in 1962, when the first experimental UHF station (WUHF) went on-air in New York City. Cited as the reason was a supposed inability for the two bands to co-exist. History - as it is wont to do - proved otherwise, due largely to UHF signals' inability to bend around natural and manmade obstruction to provide a clear signal. VHF channels 2-6 are on 54-82 MHz, 7-13 are on 174-210 MHz, and UHF channels 14-83 are on 470-884 MHz. This 1962 Popular Electronics magazine story is a very nice account of the early days of UHF television broadcasting...

Visual Basic 6.0 Wanted

Visual Basic 6.0 Software - RF CafeDo you have a copy of Visual Basic v6.0 Professional or Enterprise that you are willing to sell or swap for RF Cafe software? My VB6 was sold long ago, but now I would like to work on some old programs. Believe it or not, VB6 programs will still run on Windows 11. eBay sellers are getting anywhere from $10-$150, depending on the version. I need at least the Pro version. I could just buy one off eBay, but surely someone out there has an unused copy sitting around. Thanks - Kirt B. (kirtrfc@aol.com)

Fact Checking a la the Associated Press

Fact Checking a la the Associated Press - RF CafeHere's a March 6th headline from the Associated Press: "Fact Focus: Claims Biden administration is secretly flying migrants into the country are unfounded." It addresses recent reports that in the past year, more than 300,000 "migrants" have been flown into U.S. airports by the government. Author Elliot Spagat's keen intellect and masterful sleuthing abilities discovered that while it is true that more than 300,000 have been flow in, it wasn't a secret - it was only "enigmatic" and "lacking in transparency." Oh, and they're not coming from "who knows where," but specifically from Cuba (60k), Haiti(126k), Nicaragua(53k), and Venezuela(81), implying that unlike the millions pouring in over the Mexican border which includes people from African, Asian, and Middle Eastern countries, you can be sure none of that group are mixed in. Unmarried, military-age men make up a large, disproportionate percentage of the "migrants." Another ruse is reporting "illegal migrants," which excludes the huge number of "refugees," which is a huge number. Illegal + refugee is in the many millions. This is the very definition of gas lighting.

How We Measure Noise

How We Measure Noise, January 1973 Popular Electronics - RF CafeThis article on noise measurement is not about electrical noise, but rather on audible noise. It appeared in a 1973 edition of Popular Electronics magazine during an era when hi-fi stereo equipment was becoming a big deal. Author Carl Alsen, an engineer at General Radio, reviews methods of sound level measurement and gives values for some usual and unusual sources typically found in manufacturing environments, like a punch press, pneumatics rock drill, office and restaurant environments, and the rustling of leaves. Radio manufacturers had/have a vested interest in background noise that affects the satisfaction of their customers. Ambient noise in all realms has been a rapidly growing problem in terms of information transmission and reception. Many articles were written about background interferences in the decades of the 1960s and 1970s as more and more people became engaged (e.g., Electronic Pollution ... An Impending Crisis, Acoustical Tile - A New Hi-Fi Component, The Dolby Technique for Reducing Noise, etc.)...

RF & Electronics Symbols for Visio

RF Electronics Wireless Analog Block Diagrams Symbols Shapes for Visio - RF CafeWith 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...

Please Thank Werbel Microwave for Continued Support!

Werbel MicrowaveWerbel Microwave is a manufacturer of RF directional and bidirectional couplers (6 dB to 30 dB) and RF power dividers / combiners (2− to 16−way) with select models operating up to 26.5 GHz and 100 W of CW power (3 kW peak). All are RoHS and REACH compliant and are designed and manufactured in our Whippany, NJ, location. Custom products and private label service available. Please take a couple minutes to visit their website and see how Werbel Microwave can help you today.

Wednesday the 6th

Canada's First Satellite Station

Canada's First Satellite Station, August 1967 Radio-Electronics - RF CafeIn 1967 when this story about Canada's first satellite earth station, located 85 miles north of Halifax, Nova Scotia, appeared in Radio-Electronics magazine, government bureaucrats who oversaw the allocation of operational privilege within the realm of electromagnetic radiation worked at the Department of Transport. To some extent that makes sense since information is being transported from point A to point B. That department presently is titled Transport Canada. However, control of the EM spectrum is now the purview of the Canadian Radio-television and Telecommunications Commission (CRTC), which is the equivalent of the U.S.'s FCC. What would the world do without ever-expanding governmental powers over industry and society? We are truly blessed to have such supremely wise, intelligent, sentient beings controlling everything. No wonder today's world is so orderly and just ...but I digress. This antenna was one of only three such installations at the time in North America. Satellites were being launched with a relatively high regularity, so the population grew quickly after that. I double-checked to be sure I did not incorrectly copy the text where the author states a power level of -100 dB. That, of course, should have been dBm, since dB is a unitless ratio, not a power level. A search for an explanation of why satellites are referred to as "birds" did not turn up a definitive source. Supposedly the nickname "Early Bird" for Intelsat I stemmed from the old saying "the early bird catches the worm'" i.e. dominating the satellite industry. Other sources say "bird" refers to the satellite's path across the sky or that they have a bird's-eye view of the Earth...

Mac's Service Shop: Shelf Life of Capacitors & Batteries

Mac's Service Shop: Shelf Life of Capacitors & Batteries, August 1972 Popular Electronics - RF CafeOne of the first things a knowledgeable restorer of vintage electronic gear does prior to plugging in a newly acquired piece of hardware is to replace all of the original paper capacitors. Those things notoriously lose the internally contained smoke that makes them work soon after power is applied. Episodes of conflagration often ensue. According to Mac McGregor in this 1972 "Mac's Service Shop" docudrama published in Popular Electronics magazine, the typical shelf life of a paper capacitor (and some mica and ceramics back in the day) is about five years. In that time the insulation resistance can drop from 5000 MΩ to less than 2 MΩ. Ohm's Law quickly reveals that with used across a 300 V plate bias supply circuit, the leakage current can be 0.15 mA, and dissipate 45 mW of power. Considering the number of such connections in products like the RCA Victor Model VHR-307 Home Recording Phono-Radio Combination, the current and power can add up quickly, and the generated thermal noise can get significant. These articles, while apparently an electronics serviceman saga, is actually meant to be instructive to readers, many of whom were service shop owners or employees...

Surface Superconductivity in Topological Materials

Surface Superconductivity in Topological Materials - RF Cafe"Researchers at the Leibniz Institute for Solid State and Materials Research at IFW Dresden, Germany, have found proof for surface superconductivity in a class of topological materials known as Weyl semimetals. Interestingly, the superconductivity, which comes from electrons confined in so-called Fermi arcs, is slightly different on the top and bottom surfaces of the sample studied. The phenomenon could be used to create Majorana states – long-sought after quasiparticles that could make extremely stable, fault-tolerant quantum bits for next-generation quantum computers. Meanwhile, another group at Penn State University in the US has fabricated a chiral topological superconductor by combining two magnetic materials. Majorana states might also be found in this new material. Topological insulators are insulating in the bulk but conduct electricity extremely well on their edges via special, topologically protected, electronic states. These topological states are protected from fluctuations in their environment and electrons in them do not backscatter. Since backscattering is the main dissipating process in electronics, this means that these materials might be used to make highly energy-efficient electronic devices in the future..."

No Snow in June: Match Your TV Antenna to Rx

No Snow in June: Match Your TV Antenna to Receiver for Best Possible Picture, June 1970 Popular Electronics - RF CafeFew homeowners in the era of television antennas on the roof had any knowledge at all about how the antenna and twin lead transmission line system worked. Even those who were familiar with it only knew the basics like keeping the transmission line away from metallic objects and properly terminating the ends. I have seen photographs from servicemen of twin lead laying in aluminum guttering and along the top of chain link fence rail, and amazingly, the TV set still received a fairly good picture. That must have been in areas with exceptionally strong signals. This article in a 1970 issue of Popular Electronics magazine described a method for optimizing the antenna and transmission line in terms of impedance matching and using very low loss open ladder line to optimize signal strength to the receiver. It is exactly the subject (received signal strength) I recently lamented about being often ignored when discussing aspects of antennas and transmission lines...

Espresso Engineering Workbook™ for Excel

RF Cafe Espresso Engineering Workbook™ for Excel - RF CafeThe newest release of RF Cafe's spreadsheet (Excel) based engineering and science calculator is now available - Espresso Engineering Workbook™. Among other additions, it now has a Butterworth Bandpass Calculator, and a Highpass Filter Calculator that does not just gain, but also phase and group delay! Since 2002, the original Calculator Workbook has been available as a free download. Continuing the tradition, RF Cafe Espresso Engineering Workbook™ is also provided at no cost, compliments of my generous sponsors. The original calculators are included, but with a vastly expanded and improved user interface. Error-trapped user input cells help prevent entry of invalid values. An extensive use of Visual Basic for Applications (VBA) functions now do most of the heavy lifting with calculations, and facilitates a wide user-selectable choice of units for voltage, frequency, speed, temperature, power, wavelength, weight, etc. In fact, a full page of units conversion calculators is included. A particularly handy feature is the ability to specify the the number of significant digits to display. Drop-down menus are provided for convenience...

Tuesday the 5th

National Schools Radio Home Training

National Schools Radio Home Training, October 1942 Popular Mechanics - RF CafeIn the original radio broadcast version of "A Christmas Story," author and New York City's WOR station talk show personality Jean Shepherd mentions how during the Great Depression, desperate men fell victim to the magazine ads promising fortunes to be made repairing radios. Some, of course, actually succeeded, but doing so was difficult without substantial financial resources to fund test equipment, inventory, transportation, a workshop, etc., to get started. Two things electronics servicemen had in their favor at the time this National Schools Radio Home Training ad appeared in the October 1942 issue of Popular Electronics magazine was that many service-age men were going off to fight the Axis forces (or were planning to go), and that new radio production had ceased in order to dedicate resources to the war effort, so replacing a broken radio with a new one was not an option. The copy appeals to both the man aspiring to run his own business and the man planning to apply his knowledge and services to the military...

Channel Master Contact Cleaner

Channel Master Contact Cleaner, October 1960 Electronics World - RF CafeAsk anyone who has ever asked me to fix something electrical or electronic and they will tell you my motto on such things, born of extensive experience, is that the vast majority of the problems are caused by poor electrical contacts of one form or another. The culprit can be a dirty or broken connector, a cold or broken solder joint, a dirty potentiometer (contact between wiper and resistor), etc. I have repaired everything from ceiling lights, to car starters, to kitchen appliances, to large screen TVs simply by finding and repairing connections. When possible, I always do a final cleaning with isopropyl alcohol and then spray with a silicon contact protector. This Contact Shield product from Channel Master would be a good choice. I can honestly say I cannot think of a single instance where the restored connection failed again. Of course sometimes it is not that simple, but enough that my initial approach to troubleshooting - unless a broken or burnt component is immediately apparent - is to unplug and inspect connectors (then plug-unplug-plug to wipe contacts clean), flip switches on-off a few times while applying various directional forces (left-right, up-down, twisting), tugging on wires, etc. People's eyes light up in amazement when a sophisticated piece of equipment starts working after doing so. Then, I meticulously test and clean all other easily accessible connections...

Geoelectric Hazard Map for High-Voltage Grid

Geoelectric Hazard Map for High-Voltage Grid - RF CafeThe March 2024 issue of Astronomy magazine included this map of the U.S. showing a geoelectric hazard map for our high-voltage transmission grid. I found what appears to be the source of the information in a USGS (U.S. Geological Survey) paper entitled, "A 100-year Geoelectric Hazard Analysis for the U.S. High-Voltage Power Grid." The Astronomy piece discussed possible world-ending scenarios whose Armageddon-style event would be triggered from a space-based source. It included an asteroid strike, a massive influx of gamma rays from a supernova, a cataclysmic collapse or reversal of the Earth's magnetic field, and, regarding this thumbnail image, a significant coronal mass ejection from our own star. The renown Carrington Event which occurred in 1959 resulted in worldwide auroral displays in both hemispheres, and voltages induced in telegraph lines caused sparking between conductors and in connected equipment. There was no electric power distribution system at the time (Edison and Tesla had not yet begun their War of the Currents) or it would have experienced significant interruptions. Nowadays we have both ground- and space-based systems at risk. I'd stock up on some Doomsday food supplies, but I'd rather not be around to experience the aftermath.

Comics with an Electronics Theme

Comics with an Electronics Theme, December 1973 Popular Electronics - RF CafeYes, it's only Tuesday when this was posted, but at least it's not Monday. Electronics-themed comics appeared regularly in vintage trade magazines, like this 1973 issue of Popular Electronics. Some of the older ones require a knowledge of the norms and practices of the era. I'm not quite sure whether in the page 16 comic the beast impaled himself on the antenna, or is merely perched on it. Regardless, it is a welcome occurrence by the enthusiastic Ham radio guy. Maybe the field interruption adjusted his beam right where he needed it, or maybe he planned on his aerial doing double-duty as a fowl hunting (as opposed to fox hunting) device. RF Cafe officially does not recommend that anyone try using the temporary solution for a too-short antenna cable shown in the one comic, especially if the rig will be transmitting anywhere maximum legal output power...

RF Cascade Workbook

RF Cascade Workbook - RF Cafe 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 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...

Monday the 4th

What's Your EQ?

What's Your EQ?, December 1964 Radio-Electronics - RF CafeHere are a few brain exercises for starting a new week. They appeared in the 1964 issue of Radio-Electronics magazine in the "What's Your EQ?" feature (EQ = Electronics Quotient). E.D. Clark created over the span of a many years based on suggestions from readers. It's easy to over-think the first one, but the provided answer is more of an Occam's razor approach. The Black Box challenges can be difficult, partly because IMO the problem statement is not always clearly presented regarding what is an is not permitted as part of the solution. Here, for instance, it begins "Voltmeter tests read zero between any two terminals, so an ohmmeter (VTVM type) is connected to measure resistance." Since sometimes the generic term "voltmeter" is used in reference to a multimeter, the shift in the sentence from volts to ohms can be confusing. The zero is volts. Note that only semiconductors (diodes, transistors, etc.) are ruled out as part of the solution, not electromechanical devices. For the last one, be sure to note the restriction on frequency response...

Collapsible Helix Antenna Aids Disaster Recovery

Collapsible Helix Antenna Aids Disaster Recovery - RF Cafe"A lightweight, easily transportable antenna that can communicate reliably with either satellites or terrestrial devices depending on its spatial configuration could prove useful for coordinating disaster relief efforts. The helix-based device, which resembles a child's finger-trap toy, switches between its two operating modes as it is extended and contracted and could also be deployed in space or in areas that currently lack good communications infrastructure. Developed by researchers at Stanford University in the US and the American University of Beirut (AUB) in Lebanon, the new antenna has a mass of just 39 g and consists of counter-rotating helical strips that are connected by rotational joints and made from polymer fibre composites containing a conductive mesh. In its shortened configuration, it resembles a ring just over 2.5 cm thick and 12 cm across and can be used for targeted satellite communications. When extended, it forms a thin cylinder about 30 cm tall that sends signals in all directions, like a WiFi router. This adaptability is crucial for post-disaster search and rescue operations, explains Joseph Costantine, an electrical and computer engineer at AUB who co-led the antenna's development together with Stanford aerospace engineer Maria Sakovsky. When deployed, the antenna is mounted on a custom ground plane that reflects radio waves while allowing the antenna base to slide and change shape..."

Test Equipment Scene: VOMs, VTVMs and TVMs

Test Equipment Scene: VOM's, VTVM's and TVM's, March 1972 Popular Electronics - RF CafeFor most needs to measure voltage, current, and resistance, modern users of test equipment do not need to give much thought to the electrical characteristics of the instrument being used. Other than setting the function switch to the proper position (ohms, volts, amps, milliamps, etc.) and not exceeding the safe input limits, measurement accuracy can usually be assumed to be good to within ±2 to ±5 of the least significant displayed digit. I.e., if the digital display shows 10.000, then the actual value is likely in the range of 9.995 to 10.005. Autoranging even removes the need to manually determine the proper range setting. For critical measurements, of course, you need to actually read the documentation to get actual accuracy ranges. One critical electrical parameter of a meter is its input impedance, since its value affects the voltage / current division at the measurement point. An extreme example is where you want to measure the voltage of a unit under test (UUT) that has a 100 kΩ impedance and an open circuit voltage of 1 volt, and the meter also has in input impedance of 100 kΩ, the reported voltage will be 0.5 V...

Axiom Blog: Calibrating the Way to Process Control

Axiom Test Equipment Blog: Calibrating the Way to Process Control - RF CafeAxiom Test Equipment, an electronic test equipment rental and sales company has published a new blog post that covers the way calibrators offer the precision needed to evaluate in-process testers and how they can securely deliver test results to a control center to effectively manage an industrial process. For effective process test equipment calibration, a calibrator must be a source of precisely controlled parameters as well as a highly accurate measuring tool for evaluating the same parameters. A calibrator must often inject a parameter, such as voltage, current, pressure, or temperature, into the process equipment under test to determine the condition of the equipment. Traditionally, data transfers to and from a calibrator were handled by dedicated communications equipment. But growing demand for mobility and portability in calibrators capable of in-field use has resulted in calibrators and communicators often within the same package. When equipped with suitable communications interfaces, such as Ethernet or Bluetooth, calibrator/communication devices can quickly and seamlessly make their connections to the process equipment to be tested as well as to a control center...

Telephones Will "Ring" With Musical Tones

Telephones Will "Ring" With Musical Tones, April 1956 Popular Electronics - RF CafeIf you thought that custom ringtones have only been around since the mobile phone, you will be surprised to learn that according to this news brief in a 1956 issue of Popular Electronics magazine, Bell Telephone Labs was experimenting with such features. Bell was exploiting the convenience, small size, and relatively inexpensive transistor to enable customers with deeper pockets to hear something other than the standard mechanical bell ringer. The irony is, of course, that some people nowadays use a ringtone in their smartphones that sounds like the old mechanical ringer. Evidently the custom ringtones never went over too big for Bell because I don't remember ever hearing one in the 1960s, 70s, and 80s, and there is not a plethora of them for sale on eBay today. Being able to differentiate your own phone's ring in the midst of an environment with potentially a dozen or more other phones was not exactly a huge concern then. BTW, it wasn't until 1982 that Bell Telephone was broken up into regional "Baby Bells..."

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeBanner Ads are rotated in all locations on the page! RF Cafe typically receives 8,000-15,000 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. Your Banner Ads are displayed on average 280,000 times per year! 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...

Friday the 1st

Howard W. Sams Photofact "Win-a-Mustang" Contest

Howard W. Sams & Co., Inc. Photofact "Win-a-Mustang" Contest, December 1964 Radio-Electronics - RF CafeSam's Photofact® was the world's premier publisher of service documentation for nearly every make and model of radio, television, tape deck, projector, phonograph, and other domestic type products. By 1964 when this ad appeared in Radio-Electronics magazine, a service shop which owned a copy of every service pack ever printed had probably half a dozen file cabinets filled with folders. Manufacturers typically did not make such information available to the general public or even to shops that did not have service agreements with them. Except for some condensed versions published by magazines, and a couple other minor datapack vendors, Sam's was it. A contest drawing was used when the Ford Mustang first came out that offered a free car to the first place winner. As the ad thumbnail shows, the initial MSRP for the 1965 Mustang was a whopping $2,368 --- the equivalent of about $23,408 in 2024 money. That, of course, was the base price. It's hard to believe, but the base 2024 Mustang is only $30,920. That's 32% more than the 1965 base model, but the base today has a lot more features than in 1965. Fortunately, the new Mustangs do not feature an explode-on-impact gas tank behind the rear seat...

Dig That Reel Flat Response!

Dig That Reel Flat Response!, May 1956 Popular Electronics - RF CafeThis 1956-vintage Popular Electronics magazine article by techno-kidder Carl Kohler taught me a new word - "darb," as in "Isn't that a darb, now." According to Merriam-Webster, a darb is a slang term for something superlative. Mr. Kohler penned many tongue-in-cheek stories for Popular Electronics in the 1950s and 1960s, all of them based on his antics involving the latest electronics gadget and Mrs. Kohler's reaction to them. Maybe they are real (in this case, "reel") and maybe not, but regardless, they are funny and even if made up, could easily be actual experiences. A list of the other Kohler sagas is given below...

Dumb Move Spawned the x86 and Kickstarted PC Revolution

How a Dumb Move Spawned the x86 and Kickstarted the PC Revolution - RF Cafe"What was once considered a bad business venture, the 8008's lasting legacy went on to drive the technological world we live in today. Computer Terminal Corporation (now defunct Datapoint) launched the DataPoint 3300 computer terminal in 1969 as a platform to replace teleprinters, or the precursors to fax machines. The machine was implemented using TTL logic in a mix of small- and medium-scale integrated circuits (ICs), which could produce an enormous amount of heat during operation. When the terminal was announced in 1967, RAM was extremely expensive (and heavy). So, the DataPoint terminal stored its display of 25 rows of 72 columns of upper-case characters using fifty-four 200-bit shift registers, arranged in six tracks of nine packs each, providing shift register memory for 1,800 6-bit characters. To address the excessive heat and other issues, CTC designed the DataPoint 3300's predecessor with a CPU, placing all of those ICs on a single chip. CTC co-founder Austin Roche looked to Intel to help with the endeavor, as the company was well known for being a primary vendor of RAM chips at the time..."

Thin TV Display Panel

Thin TV Display Panel, January 1973 Popular Electronics - RF CafeAlthough not routinely referred to as plasma displays at the time, the "thin TV displays" reported in this 1973 article in Popular Electronics magazine was one of the first instances of commercially viable schemes. According to Wikipedia, Fujitsu introduced the first full-color plasma display panel (PDP) in 1992 - with a 21" screen - two decades after this device 80x212-pixel monochrome designed by Zenith. I remember seeing the 42" Fujitsu plasma TVs in Best Buy with a $10,000 price tag sometime in the mid 1990s, which jives with Fujitsu's stated plan of selling the first units at around 1 million yen (~$8,800 at today's exchange rate). Prior to the advent of plasma displays, rear-projection screen televisions were the main way to get really large displays. While rear-projection displays suffered from narrow viewing angles, plasma displays suffered from pixel burn-in that gradually reduced contrast to annoyingly low levels. Both options carried a relatively large price tag compared to 25" and 27" CRT televisions...

Espresso Engineering Workbook™ for Excel

RF Cafe Espresso Engineering Workbook™ for Excel - RF CafeThe newest release of RF Cafe's spreadsheet (Excel) based engineering and science calculator is now available - Espresso Engineering Workbook™. Among other additions, it now has a Butterworth Bandpass Calculator, and a Highpass Filter Calculator that does not just gain, but also phase and group delay! Since 2002, the original Calculator Workbook has been available as a free download. Continuing the tradition, RF Cafe Espresso Engineering Workbook™ is also provided at no cost, compliments of my generous sponsors. The original calculators are included, but with a vastly expanded and improved user interface. Error-trapped user input cells help prevent entry of invalid values. An extensive use of Visual Basic for Applications (VBA) functions now do most of the heavy lifting with calculations, and facilitates a wide user-selectable choice of units for voltage, frequency, speed, temperature, power, wavelength, weight, etc. In fact, a full page of units conversion calculators is included. A particularly handy feature is the ability to specify the the number of significant digits to display. Drop-down menus are provided for convenience...



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