RF Cafe Software
About RF Cafe
1996 - 2022
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...
All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.
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to Find What You Need.
There are 1,000s of Pages Indexed on RF Cafe !
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.
Homepage Archive Pages
2017: Jan |
Jun | Jul |
2016: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2015: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2014: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2013: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
Here is page 2 of the April 2015 homepage archive.
Oscilloscopes for Radio
Amateurs: Add to Ham Shack
Oscilloscopes for Radio Amateurs: Add a Scope to Your Ham Shack, by Paul Danzer, is filled with practical information you’ll need for using a scope. It begins with an overview of the oscilloscope and continues on to discuss characteristics, applications, probes, controls, and input modes. If you’re considering adding this piece of test equipment to your ham shack, there is an explanation of scope specifications and features to help you select an oscilloscope that is right for you.
Path Loss, Propagation Time,
& Doppler Radar Pages Updated
The latest RF Cafe reference pages to be update are Doppler, Path Loss, Propagation Time, and Radar Equation. As with the others, graphics have been improved and page content reformatted to be (hopefully) more user friendly. Please let me know if you spot any problems. Thanks.
Hiram Percy Maxim Dies
Hiram Percy Maxim is a name known to every American licensed amateur radio operator, since he was the primary found of the American Radio Relay League (ARRL). This obituary that was printed in the May 1936 edition of Radio-Craft reported on his death at age 66 (the article incorrectly says 67 years old) - young by today's standards, but about normal a century ago. Although he lived in Connecticut, he was buried in Rose Hill Cemetery, located in Hagerstown, Maryland. A couple years ago, Melanie and I were visiting her mother, who lives in Hagerstown (we once lived there as well), and set out to locate his place of final rest. I wrote about in this story titled "Hiram Percy Maxim's Gravesite in Hagerstown, Maryland."
Orbel Honored with Governor’s
Orbel Corporation is being honored with a Small Business ImPAct Award as part of the third annual Governor’s ImPAct Awards, recognizing businesses that create jobs and generate an economic impact within the state. The Small Business ImPAct Award is given to a small business (100 or less employees) that is an innovator within its industry, demonstrated revenue/profit growth, increased its workforce, and is committed to the growth and development of its employees and community. Orbel’s EMI/RFI shielding technology has helped to usher in automation to nearly all industries, promoted the viability of manufacturing within the …
An Electronic Quiz
Thyratrons, klystrons, and magnetrons I've heard of, but trochotrons, charactrons, tonotrons I ain't heard of. That made this quiz more of a learning exercise for me than a test of any sort of knowledge possessed. I thought an 'ignitron' was a pejorative term for a really dumb techie wannabe. In all there are 17 types of '-tron' devices given for which to match from a list of descriptions. You'll probably do better than I did …
Heuermann HF-Technik 2.45 GHz
Generators & Plasma Jets
HHF is the first company who offers generators (PlasMaster) in the power range between 10 W and 200 W including a control circuit to fulfill hot S-parameter measurements and to look on the best S11-value in the IMS-band. Additionally plasma jets from 10W-MiniJet up to 200W-PCA jet with cannula for cleaning, disinfection, activating, coating, melting and welding, as well as a low power generators, low pressure chamber coupler, and more support equipment.
Notable Tech Quote
"Because we now have shared calendars, people can kidnap our time." - Leigh Buchanan, The Psychology of Productivity, Inc magazine.
Thunderbolts and Whistlers
The first electronic circuit I remember building as a budding teenage tinkerer was a 'whistler' detector, aka a 'sferic.' Instructions and a schematic came from a project book I bought at Radio Shack. A whistler is a time-varying electromagnetic signal that decays in both frequency and volume over a short time - like sounds made by the eponymous fireworks genre. Having always had an interest in weather phenomena as part of my flying hobbies,, it seemed like an apt learning endeavor. To my recollection, the whistler detector was a simple diode circuit with a couple Rs, Ls, and Cs strewn around in a particular configuration, and a long wire antenna. I can't honestly say …
RF Cafe's RF Calculator
Workbook Updated to v7.1
While updating the Doppler frequency reference page, I discovered an error in the free RF Calculator Workbook v7.0. It does not properly adjust the units based on user settings. I just posted v7.1 to fix the issue. RF Calculator Workbook v7.1 can be downloaded now, also for free. If you purchased the unlocked version, please contact me and I will send you a replacement. Please forgive the inconvenience.
The "G-Line" Community
When I first saw this article on the 'G-line' transmission system, I though the cone at each end of the line was just a gimmick to make it look high-tech. My ignorance of the way the system works was responsible. As it turns out, the 'G-line' transmission medium, named after inventor Dr. Georg Goubau, an engineer at the renowned U.S. Army Signal Corps Engineering Laboratories at Fort Monmouth, NJ, used the cone to transition a finite radius coaxial cable outer conductor to an infinite radius, sort of virtual, outer conductor that was free space. Doing so permitted a single line to do the job of carrying a signal from point A to point B. This significantly reduced the installation and maintenance cost of deploying …
Bell Telephone Laboratories
Ad: Transatlantic Cable
Prior to satellite communications, long-distance messages were carried by footmen, horses and riders, smoke signals, trains, airplanes, boats, lanterns, sign language, printed media, radio frequency, and cables. All had their advantages and disadvantages, but none other than cable could provide reliable, nearly instantaneous conversations across and between continents - or cities for that matter. Stringing wires on poles over the landscape was a relatively simple task compared to that of laying cable along the ocean floor. Maintenance on underwater cable and amplifiers was exceedingly difficult or even impossible in some sections. Developing a suitable insulation to withstand the harsh salt water environment and the extreme pressures at great depths …
Invisible Light Aids Marksman
"What's the big deal about a night vision scope for your rifle?," you might ask, since "I can buy an infrared scope for my rifle on Amazon for under $100." The answer is that no, it is not a big deal now, but in the 1940s while it was being developed and deployed for the military, it was Top Secret. Just radar is a yawn in any discussion of leading edge technology today, it was vital to keeping the free world free. It wasn't until after World War II had ended that infrared scopes found their way into unclassified articles, but even then the cost was way more than any non-governmental entity could afford. The Barska IR scope from Amazon is not a top-end product, but chances are that being all solid state, it …
XMA 40 GHz Termination Family
with Zero Outgassing Emissions
XMA Corporation, a leader in advanced microwave and RF products, announced the release of high frequency terminations with zero outgassing features. A recent independent test performed by Integrity Testing Laboratory (ITL) confirmed an important finding that 40 GHz millimeter wave terminations manufactured by XMA Corporation meets ASTM Method E 595 Total Mass Loss and Collected Volatile Condensable Material (CVCM) standards. Under a controlled temperature and humidity environment, the assemblies …
Antique Coat Rack
In case you are a fellow woodworker: For as long as both Melanie and I can remember this old coat tree has been standing in her parent's house - first in Hagerstown, Maryland, then in two locations in West Virginia, and finally back in Hagerstown, Maryland. After her mother moved into a senior care home, we 'inherited' it, which was great for me because, being obviously old, I really liked it. As you can see from the 'before' picture, it was in pretty rough shape …
& Data Chart
Here is a vacuum tube chart everybody needs. Well, not really, but surely somebody out there in the RF Cafe audience will find it useful. By 'audience' I mean most likely a hobbyist who is restoring or repairing a vintage tube-type radio, television, piece of test equipment, etc., who has never even heard of RF Cafe, but finds exactly what he (or she) needs as the result of a Google (Bing, Yahoo, whatever) search. If it seems like you can find information on just about anything you need on the Internet these days, it is at last partly because of efforts like …
Improved Integrated Workflow
for Optenni Lab and ANSYS HFSS
Optenni Ltd announces an improved link between ANSYS® HFSS and Optenni Lab™ for designing matching circuits for antennas and RF components based on 3D models simulated with HFSS. This tight integration is made possible by the new ANSYS® Electronics Desktop™ technology included with HFSS. It delivers a new paradigm for electronic design with highly productive drag and drop dynamic links between electromagnetic field extraction and circuit simulation for easy problem set-up and reliable product performance.
An important challenge in the daily work of antenna design engineers is to ensure that …
Engineering Career Advice
Headlines have been reporting good times are rolling around most of the world for just about anyone with high tech skills who is looking for a job. We here in the U.S. evidently cannot grow enough engineers, technicians and scientists domestically fast enough to fill increasing demands by employers, so Congress is repeatedly increasing the number of every type of work visa on the books to facilitate the importation of qualified people. I say "evidently" because depending on who you ask, a large part of the motivation for hiring foreign talent is to take advantage of being able to exploit their vulnerability to demands of lower pay and more more hours …
New Titles Added to Book
Contest Pick List
If it has been a while since you looked through my list of titles available as part of the monthly Book Drawing contest, now would be a good time since four new books were just added. Thanks to the generosity of publishers like Artech House, Cambridge University Press, and McGraw Hill, I have been able to offer a book or two every month to RF Cafe visitors who have entered via a simple process. To date, about 120 books have been given away. Not only are the books made available for free, but I have personally paid for postage on all of them - even the many shipped to overseas winners. These books typically carry a retail price of well over $100, and they are of course of very recent publication since I receive them from the publishers to review often times prior to …
Directional Coupler Reference
Re-work of the directional coupler reference page on RF Cafe is complete. As with many of the other pages, I am updating the drawings and textual information to bring them up to 2015 standards that allow for more bandwidth than back in the early 2000s when they were first designed; i.e., more HTML-based formatting and larger graphics. Please take a look if you have a chance and let me know if I got anything wrong. Thanks.
RFMW Introduces 1200 MHz
MiniRF Passive Splitter
RFMW, Ltd. announces design and sales support for a 5 to 1200 MHz passive, 2-way splitter from MiniRF. The MRFSP5725 provides a low cost, highly reliable solution for broadband CATV designs. Characterized for use in 75 ohm circuits, the MRFSP5725 offers 28 dB of isolation with typical insertion loss of only 0.5 dB. Lead free and RoHS compliant, the MRFSP5725 comes in a surface mountable 0.15 x 0.15 x 0.115" package. Amplitude balance measures 0.2 dB with phase balance of 1.5°. The MRFSP5725 joins the MiniRF 5 to 1002 MHz model MRFSP0014 in a series of low-cost splitters for broadband …
Reactel, designer and manufacturer of RF & Microwave Filters, Multiplexers and Multifunction Assemblies, announced today that it has achieved AS9100 certification. AS9100 is a quality standard for companies that design, develop, or produce aerospace products. Reactel’s AS9100 certification is a dual certification, meeting all of the requirements of ISO 9001as well as the additional requirements specific to the aerospace industry. Prior to receiving AS9100 certification, Reactel had been ISO 9001 certified since 1996. “AS9100 certification will benefit all facets of Reactel’s operation. Its …
Calls Home from Auto
by Short Wave
This could be one of the earliest reports of mobile communications between a private automobile and a home base station. Using a personally designed and installed 5-meter transceiver both at home and in his car, Mr. Wallace is able to talk to his 12-year-old son on the way from work. My guess is that in 1935 there were not too many traffic jams, even in Long Beach, California, being the cause for his announced expected later than normal arrival. The auto power supply needed to produce 300 mA of current at 525 V (~160 W). My question is whether little Billy possessed a license permitting him to talk back to dear old dad from the home station? If not, it really doesn't matter at this point since there is probably some statute of limitations that absolves him from …
$5.00 for Best Short Wave Kink
August 1935 Short Wave Craft
You might not have the need for a variable capacitor made from a match box and a couple strips of tin foil, but there are plenty of other 'kinks' offered here that could be of use to you when the 'right' part is not available. For instance, maybe a transformer exhibits an audible hum because of improper construction, or maybe a vernier dial is needed for an adjustment knob. In all, there are 11 tips from way back in 1935 offered by fellow radio enthusiasts.
RF & Microwave Magazine
Articles for April
A lot of new articles have been posted by the well-known RF and microwave industry magazines since I last created a list like this. The items below are ones that particularly interest me, but once you click on one of them to get to the article, you can easily get to the magazine's homepage to see what else is available. Here is a complete list of all featured RF & microwave articles.
CW Geek's Guide to Having
Fun with Morse Code
CW Geek's Guide to Having Fun with Morse Code, by Dan Romanchik (KB6NU). Says Dan, "I thought some of your readers might be interested in my latest book. As you know, passing a Morse Code test is no longer required to get an amateur radio license, but there's still a mystique about Morse Code, and if you tune into the ham bands any evening or on the weekend, you'll find that the music of CW (as we call it) is alive and well."
Microwave Filter Company
Intros 3 New UMTS Filters
Microwave Filter Company announces the addition of three new UMTS (2100 MHz) cavity filter products. Prices begin at $425 each. Microwave Filter Company offers a variety of products to service the UMTS band. Products include transmit band, receive band filters and full band duplexers.
Here are a four more electronics-themed comics from magazines of the days of yore, this time from a 1948 edition of Radio-Craft magazine. Evidently Radio-Craft readers would submit ideas for funnies and then artist Frank Beaven would draw the comics. My interest in rockets makes me really appreciate the one with the missile's flight being affected by the musical 'interference.' It is rare to find a comic in a technical or hobby magazine these days. I don't know why that is. Enjoy. …
Notable Tech Quote: Carl Sagan
"A googleplex is precisely as far from infinity as is the number 1 ... No matter what number you have in mind, infinity is larger." - Carl Sagan. Sagan's Cosmos: A Personal Voyage series on PBS in 1980 is largely responsible for my interest in astronomy as a hobby. Although I had a small el cheapo 2" Tasco refractor telescope, a desire to view the kinds of deep space objects featured on Cosmos prompted me to scrape up $120 (a lot of dough in 1980) for a 6" Newtonian type reflector telescope. A lot of people have had a magnified look at the surface of the moon if from nothing else a camera telephoto lens, but viewing Saturn's rings and Jupiter's moons through a 'real' telescope will take your breath away. They seem unreal. For a real intellectual and even emotional rush, use an 8-inch or larger telescope to view a globular star cluster like Messier 13 in Hercules or the amazing cluster of galaxies in Coma Berenices. A picture doesn't come close to replicating the 3-dimensional perspective of the view through an eyepiece.
What Describes Your Primary
Involvement in Electronics
Silicon Controlled Rectifiers
New Applications in the Home
Silicon controlled rectifiers (SCR) have been around for half a century and are still workhorses in power control and switching circuits. The SCR's usefulness comes both from being a diode with a settable forward conduction point ('breakover voltage') and its property of continuing to conduct below that threshold voltage once it has been reached. It then stays 'on,' acting like a conventional bipolar junction diode until p-n junction is no longer forward biased. At that point the diode is 'off' again until the breakover voltage is once again reached. When a sinewave is applied, as in a power supply design, this action allows the SCR to be turned on for less than half a cycle as a standard diode would do. Yes, you could design a biasing circuit to prevent a standard diode from conduction until …
Cascaded IP2, IP3, P1dB & NF
Back when I first created the reference pages for mathematically cascading IP2, IP3, NF, and P1dB values, conservation of Internet bandwidth was a serious concern that required streamlining content - particularly images. Equations were mostly presented in text format with whatever HTML stylizing tags were available. As preparations continue for a smartphone app and maybe even a computer program, I am updating many pages that have not been touched in years. Please take a look when you have a chance.
Anatech Electronics Intros
3 New Duplexer Designs
Anatech Electronics offers the industry's largest portfolio of high-performance standard and customized RF and microwave filters and filter-related products for military, commercial, aerospace and defense, and industrial applications up to 40 GHz. Anatech has released three new filter designs: a 3437.5 & 3537.5 MHz connectorized cavity duplexer filter, a 2067.5 & 2475 MHz connectorized band combiner filter, and a 897.5 & 942.5 MHz connectorized ceramic …
Phillip S. Is Another Winner
in the March 2015 Drawing!
Phillip S., of Pueblo West, CO, is the second winner in the March 2015 RF Cafe Book Drawing. Phillip selected The Satellite Communication Ground Segment and Earth Station Handbook, by Bruce Elbert. Each month I draw a name or two randomly from a list of people who have bought my software and offer a choice of a free top grade technical book from publishers like Artech House and Cambridge University Press. I pay shipping costs as well. Ain't I a nice guy?
RF & Microwave Engineering
Take a break and work this week's RF & microwave engineering themed crossword puzzle. All the words are pulled from a hand-built list of terms, names, and abbreviations that have only to do with science, mathematics, and engineering. If you want a crossword with names of movie stars and obscure countries, try the local newspaper. If you want to exercise your nerd knowledge, this is the one for you.
$5.00 for Best "YL" Photos
News headlines are filled with stories about how certain segments of the society are routinely excluded from participation in activities which have been historically 'dominated' by adult white males - not unlike Santa's sleigh propulsion units banning poor Rudolph from join in any reindeer games. Not only have 'outsiders' been prevented from engagement, but, you would likely concluded based on the invective words that drip from the pens and/or mouths of those reporting, tireless campaigns have been mounted to see to it that exclusiveness continues. I will agree that there have been instances of preferential treatment by some groups and people, but I also know many attempts have been made over the decades to attract other than white males into all …
Asia Pacific Circuits Co. Added
to Substrate, PCB Fab & Assy
Asia Pacific Circuits has been added to the RF Cafe "Substrate & PCB Fabrication & Assembly" vendor page. PCB & PCB assembly contract manufacturer provides high quality, low-cost PCB fabrication & full turn-key PCB assembly. Electronic CM services for multilayer PCB 1-60 layers, HDI, BGA, flexible/rigid PCB; Rogers, aluminum, Teflon PCB. PCBA capabilities: SMT, through-hole, mixed, & BGA assembly.
100 W Iso-Attenuator
Protects and Monitors
RFMW, Ltd. announces design and sales support for the Iso-Attenuator model RFSL2536-A30 from RF Circulator Isolator, Inc (RFCI). RFCI Iso-Attenuators protect active components from distortion or potentially damaging reflected power while providing a convenient, attenuated port for monitoring RF power. As part of a feedback loop, the 30 dB attenuated signal allows RF power to be regulated. The RFSL2536-A30 is capable of handling 1000 W peak / 200 W average forward power and 100W CW reverse power into the on-board, 30 dB attenuator. Spanning 1920 to 2125 MHz, the RFCI RFSL2536-A30 provides >23 dB typical …
An Ex-Ham's Opinion
of "No-Code" Test
I tend to be a traditionalist for most things, but don't go out of my way to make trouble for other people who don't appreciate the way things are and have been... as long as, per Thomas Jefferson, "It neither picks my pocket nor breaks my leg." In other words, if your actions cause me no financial or physical harm, I'm not likely to oppose your actions - unless they're illegal. Many older Hams are greatly offended at the FCC for having removed the Morse code requirement in 2005 for obtaining an amateur radio operator's license. They see it as a way to separate the wheat from the chaff, so to speak; that is to say, to maintain a barrier that keeps non-serious aspirants from gaining entry into the ranks of the elite group of communications hobbyists …
Japan Short-Wave Phone
to America Open
"Tokyo is now a next-door neighbor-thanks to the magic of short-waves." That statement was made in a 1935 edition of Short Wave Craft magazine after the American Telephone and Telegraph (AT&T) company completed its wireless phone (voice) link between the U.S. and Japan; which is the first 'T' in AT&T. Most people today would probably have a hard time guessing that the second 'T' in AT&T stands for 'telegraph.' Its surprising that the name has not been changed to reflect the outdated-ness. Western Union sent its final telegraph in 2006. Another news headline a couple years ago reported on India …
Congrats to March 2015
Book Winner Pamela N. !!!
Pamela N., of Eldersburg, MD, is the March 2015 book drawing winner. Pamela opted for Chipless RFID Reader Architecture. Each month I randomly select a name or two from people who have bought RF Cafe software products during the month. Not only is the book free, but I pay postage out of my own pockets. To date more than Graciously provided by Artech House
Microwave Journal Releases
Educational Video Library
Microwave Journal announces the release of Microwave Media, a new video platform for educational and demonstration videos and other multi-media content, such as webinars and slide shows. Microwave Media has hundreds of videos that are organized by application, product, event and company, including the popular Microwave Journal bi-monthly series, Frequency Matters. The video platform allows editors, with a click of the mouse, to curate entire channels of quality content from sites such as YouTube and Vimeo. The curated videos complement Microwave Journal’s exclusive webinars produced with …
From Dream House
IMS ExpertServices periodically sends me e-mails that highlight recent key court cases that can significantly affect the effectiveness of expert testimony, both for the plaintiff and for the defendant. Joshua Fruchter's latest article titled "From Dream House to Courthouse" reports on contract law involving a well-known celebrity's epic battle with a major endorsement and promotion corporation that clearly attempts to leverage said celeb's trademark lack of cerebral fortitude. Mr. Fruchter's grasp and analysis of the situation once again reminds me that if I am ever in need of expert witness testimony, he will be at the top of my list for who to call! …
Kluge Electronics Ad
Having an unusual last name like 'Blattenberger' in the U.S. has caused me a lot of abuse over the years as many people have felt the need to either purposely mispronounce it or make make snide comments about its length and number of syllables. Even school teachers joined in the fray, especially on the first day of class when attendance was being taken. My drill sergeant in USAF basic training, TSgt. Ramerez, chided me about it (circa 1978). People in America with surnames of German origin were often the victims of physical abuse, alienation, and derision during both World War I and World War II. You hear a lot about the government's internment of Japanese Americans during WWII, but some Germans were also rounded up merely because of their names. The truth is poking fun at my …
Small Antennas: Miniaturization
Techniques & Applications
Small Antennas: Miniaturization Techniques & Applications, by John Volakis, Chi-Chih Chen, and Kyohei Fujimoto. "The most up-to-date methods on the theory and design of small antennas, including an extensive survey of small antenna literature published over the past several years. Written by experts at the forefront of antenna research, [this book] begins with a detailed presentation of small antenna theory--narrowband and wideband--and progresses to small antenna design methods, such as materials and shaping approaches for multiband and wideband antennas. Generic" …
Skyworks Intros Low Profile
5 GHz 802.11ac/n FEM
Skyworks introduces a highly integrated, 5 GHz 802.11ac/n front-end module for mobile platforms including smartphones and tablets. The fully matched SKY85716-11 FEM incorporates a 5 GHz single-pole, double-throw transmit/receive switch, a 5 GHz low noise amplifier with bypass and a 5 GHz power amplifier. Its0.33 mm package height makes it suitable for low profile SiP modules in embedded systems. Direct to battery 3.0 V to 5.0 V operation eliminates the need for an LDO regulator, reducing overall bill-of-material costs. The SKY85716-11 meets tough linearity targets with 17.5 dBm MCS7 and 16 dBm MCS9 output power at …
Proposed 6G Cellular Standard
In a move reminiscent of Microsoft announcing skipping from Windows 8.1 directly to Windows 10 in order to emphasize the significant step in functionality, the NexGen Mobile Network Alliance circulated a press release detailing plans to skip past the in-process 5G standard (originally slated for a 2020 release date) and proceed with 6G. Unanticipated advances in breakthrough quantum computing algorithms, terabit data rates over dilithium optical cables, and transmutational hypercubic encoding schemes has prompted regulators to abandon work on 5G after hardware manufacturers including both phone and tower equipment companies petitioned the standards body to save them the engineering and production costs that would be involved in supporting what would certainly be a very short term compliance requirement …
"Necessity is the mother of invention," is a common saying that proves itself to be particularly true in times of war. World War II launched scientists and engineers belonging to both the Axis and the Allied powers into inventive frenzies in their efforts to hasten an end to hostilities; of course each side also wanted to be the victor. We all know how the story ended. Although some countries were not immediately able to capitalize on their countrymen's technical advances, within about a decade normalized relations had been established between former foes, and the exchange of products, services and scientific information proceeded. Some discoveries were deemed too valuable to national security and were therefore not divulged even, in some instances, to friendly nations. Many scientists consider themselves to be …