Homepage Archive - March 2021 (page 1)

See Page 1 | 2 | 3 | 4 of the March 2021 homepage archives.
col-width

Sunday the 7th

RF Engineering Theme Crossword Puzzle for March 7th

RF Engineering Theme Crossword Puzzle for March 7th, 2021 - RF CafeThis RF Engineering Crossword Puzzle for March 7th has many words and clues related to... you guessed it... RF engineering - and mathematics, chemistry, physics, and other technical words. As always, this crossword contains no names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort unless it/he/she is related to this puzzle's technology theme (e.g., Hedy Lamarr or the Bikini Atoll). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy!

Friday the 5th

Design Tips for Rewinding Your Own Transformers

Design Tips for Rewinding Your Own Transformers, October 1944 Radio News - RF CafeNot many people rewind transformers these days, but then even in 1955 when this "Design Tips for Rewinding Your Own Transformers" article appeared in Radio News magazine not many were rewinding transformers. Plenty of radio repair servicemen did, though, because replacements were expensive and getting replacements for other than common transformers could take a long time. There was no searching for one on the Internet and having it delivered in a couple days. Since many - if not most, by necessity - electronics repair shops kept subscriptions to available trade magazines, publishing an article like this provided a great service. Author James Dolan provides all the necessary information for either designing your own transformer from scratch or for modifying an existing transformer to meet your specific requirements...

Many Thanks to Nova Microwave for Continuing Support!

Nova Microwave Circulators & Isolators - RF CafeNova Microwave is a leader in technically differentiated electronic and radio frequency Ferrite Circulators and Isolators that connect, protect and control critical commercial and military wireless telecommunications systems. Our staff is dedicated to research and development of standard and custom design quality Ferrite Circulators and Isolators from 380 MHz to 26.5 GHz. Available in single or multi-junction topographies, the Nova Microwave product line of is specifically designed for use in varied environmental and temperature extremes. 

Reconfigurable Electronics Based on Multiferroics and Nanomagnetism

Reconfigurable Electronics Based on Multiferroics and Nanomagnetism - RF Cafe "Research could lead to the development of new materials with large magnetoelectric (ME) coupling for next-generation multifunctional devices, including, multi-state (neuromorphic-like) circuits and memories, and E-field tunable microwave resonators for secure communications. Multifunctional magnetoelectric materials with high exchange represent a missing 'holy grail' of materials physics. To combine polarization and magnetization in the same solid is nothing short of actually controlling the fundamental nature of electromagnetism in matter. Although magneto-electricity (ME) is an intrinsic phenomenon in some natural materials at low temperature, such single-phase materials suffer from an extremely weak ME exchange..."

Rubberized Circuits for Guided Missiles

Rubberized Circuits for Guided Missiles, February 1957 Radio & Television News - RF CafeYou can go to just about any store these days and buy a tube of RTV (room temperature vulcanizing) rubber caulk. That was not the case as recently as the 1960s and 1970s. Here is a short news item about how Dow Corning Corporation's breakthrough new compound was set to revolutionize hermetic sealing of critical electronic assemblies. It shows entire subassemblies of connectors, wires, and discrete components (no ICs at the time) completely encapsulated in the stuff. I remember at Westinghouse Electric, where I worked as a technician after a tour in the USAF, we used RTV for sealing bulkhead-mounted connectors on torpedo heads and towed sonar arrays. We also used massive quantities of it to seal off machined metal molds for ceramic transducer element arrays prior to potting them with a polyurethane compound. That was cool work. The heavy aluminum molds, about 6-feet long, were placed in a huge, thick-walled aluminum tube and a vacuum...

The Math Behind the Smith Chart

Math Behind Smight Chart - RF CafeMany of us are familiar with the math behind the Smith chart. Some have written spreadsheets and software for creating Smith charts, if only for the satisfaction of being able to do so. It really is quite simple (complex, actually - get it?) to do, but as with most things a genius mind (i.e., Phillip Smith) was needed to think of doing it in the first place. John Dunn, a very smart guy in his own right, posted a good primer on the subject on the EDN website. If you are new to the Smith chart or just want to do a refresh, then surf on over to read his article, and maybe click on the three related links at the bottom for more info.

Many Thanks to Centric RF for Their Continued Support!

Centric RF microwave components - RF CafeCentric RF is a company offering from stock various RF and Microwave coaxial components, including attenuators, adapters, cable assemblies, terminations, power dividers, and more. We believe in offering high performance parts from stock at a reasonable cost. Frequency ranges of 0-110 GHz at power levels from 0.5-500 watts are available off the shelf. Order today, ship today! Centric RF is currently looking for vendors to partner with them. Please visit Centric RF today.

Thursday the 4th

Electronics-Themed Comics from 1954 Radio-Electronics

Electronics-Themed Comics, June 1954 Radio-Electronics - RF CafeHere for your enjoyment are a few more tech-themed comics from a vintage Radio-Electronics magazine. Television antenna installations and stereophonic audio systems were a big deal back in the day, so lots of comics were centered on the themes. Everything was new and mystical, and ownership of a top-end TV or stereo was a real sign of influence and/or savvy. The comic from page 96 is actually an advertisement for Jensen phonograph needles, which of course were key components to the aforementioned stereo systems. Lost on Millennials (not their fault) and later is probably the allusion to how the bedraggled couple needing to resort to a Flintstones-style (also likely unfamiliar to Millennials) record player...

IEEE Engineering Salary Survey 2020

IEEE Engineering Salary Survey 2020 - RF CafeAccording to this engineering salary report for 2020, pay continued on an upward trend in the U.S. despite the Wuhan Flu debacle. Data collected by technology career company Dice indicated the average salary (not including benefits, bonuses, etc.) of a tech professional in the U.S. increased 3.6% to $97,859 in 2020. Dice based its numbers on a survey of about 9,000 tech employees - which does not really seem to me like a very significant sample size. Looking at the bar chart, most areas reported an increase in salaries, with on the extreme Northwest cities of Seattle and Portland losing ground. The Silicon Valley area went from $123,826 to $126,801, a meager 2.4% increase when living in a land where software developers domicile in their cars due to the cost of housing. Only augmented and virtual reality (AR and VR) software engineers saw a significant increase (13%).

Breakthrough in Quantum EW to Monitor Entire RF Spectrum

Breakthrough in Quantum EW to Monitor Entire RF Spectrum - RF Cafe"Using laser beams to create excited Rydberg atoms, Army researchers say they built a quantum sensor to detect the complete radio frequency spectrum. The findings, published in the Physical Review Applied, show the Rydberg sensor can pick up Bluetooth, Wi-Fi, AM and FM radio, and other communications signals on frequencies as high as 20 GHz. Although more engineering and physics work is necessary, the device has the potential to unleash new potentials for military communications, spectrum awareness, and quantum electronic warfare (EW). Using the lasers, rubidium atoms are excited into desired Rydberg states, allowing researchers to measure atoms' response to an electric field and hone in on a portion of the spectrum they wanted to measure. Because Rydberg atoms are extremely sensitive to the circuit's electric fields..."

A "WAVE" in Naval Electronics

A "WAVE" in Naval Electronics, March 1957 Popular Electronics - RF CafeOddly, the article does not tell you the origin of the acronym "WAVES." From the U.S. Navy's history page: "After a twenty-three-year absence, women returned to general Navy service in early August 1942, when Mildred McAfee was sworn in as a Naval Reserve Lieutenant Commander, the first female commissioned officer in U.S. Navy history, and the first Director of the WAVES, or "Women Accepted for Volunteer Emergency Service". In the decades since the last of the Yeomen (F) left active duty, only a relatively small corps of Navy Nurses represented their gender in the Naval service, and they had never had formal officer status. Now, the Navy was preparing to accept not just a large number of enlisted women, as it had done during World War I, but female Commissioned Officers to supervise them. It was a development of lasting significance, notwithstanding the WAVES' name, which indicated...

Make Sure That Electric Car Does Not Run out of Juice

Axiom Blog: Make Sure That Electric Car Does Not Run out of Juice - RF CafeAxiom Test Equipment, an electronic test equipment rental and sales company, has published a new blog post entitled, "Make Sure That Electric Car Does Not Run out of Juice," that informs people who are looking to monitor the battery and charging system of their electric vehicle (EV), hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV). Learn how you can maintain a healthy and high performing battery through our informative guide. In order to ensure that your EV is driving smoothly, you must do careful maintenance of the battery and powertrains. Two of the most significant tests includes an internal resistance test and a battery capacity / discharge test. Doing these tests with the proper equipment will allow you to see if your EV can handle short circuits, over-voltage conditions, and over charging...

Many Thanks to ConductRF for Continued Support!

ConductRF coaxial cables & connectors - RF CafeConductRF is continually innovating and developing new and improved solutions for RF Interconnect needs. See the latest TESTeCON RF Test Cables for labs. ConductRF makes production and test coax cable assemblies for amplitude and phased matched VNA applications as well as standard & precision RF connectors. Over 1,000 solutions for low PIM in-building to choose from in the iBwave component library. They also provide custom coax solutions for applications where some standard just won't do. A partnership with Newark assures fast, reliable access. Please visit ConductRF today to see how they can help your project! 

Wednesday the 3rd

U.H.F. Transmission Lines and Converters

U.H.F. Transmission Lines and Converters, June 1954 Radio-Electronics - RF CafeAbout the only kind of transmission line homeowners use today is 75 Ω coaxial cable for television and Internet connections. Up until the turn of this new century (two decades old by now - ugh!), a fair percentage of TV owners still had an antenna mounted on the roof or maybe rabbit ears sitting atop the set. Twin lead transmission line was still a common sight as at least the "last mile" (last few inches, actually) connection via an impedance converter to the pair of screws on the back of a TV or FM radio. By then, most TVs also had an "F" coaxial connector for direct attachment without a converter. Internet connections at the time were telephone cords connected to the modem board inside your computer. It's hard to believe that was just a relatively few years ago that we early WWW users got to cross our fingers when dialing up a local phone number for AOL, Earthlink, Compuserve, Prodigy, Mindspring...

Speed Limit Also Applies in Quantum World

A speed limit also applies in the quantum world - RF Cafe"Even in the world of the smallest particles with their own special rules, things cannot proceed infinitely fast. Physicists at the University of Bonn have now shown what the speed limit is for complex quantum operations. The study also involved scientists from MIT, the universities of Hamburg, Cologne and Padua, and the Jülich Research Center. The results are important for the realization of quantum computers, among other things. They are published in the prestigious journal Physical Review X, and covered by the Physics Magazine of the American Physical Society. Suppose you observe a waiter (the lockdown is already history) who on New Year's Eve has to serve an entire tray of champagne glasses just a few minutes before midnight. He rushes from guest to guest at top speed..."

RF Test Technician / Associate Engineer Needed by Safe-Com Wireless

RF Test Technician / Associate Engineer Needed by Safe-Com Wireless - RF CafeSafe-Com Wireless designs and manufactures wireless communications equipment for first responders. The equipment comprises boosters and fiber optic distributed antenna systems. The equipment is used inside buildings to permit the first responder to communicate during emergence incidents. The Radio Frequency Test Technician / Associate Engineer position requires minimum 5 - 15 years direct experience in RF board level testing using a spectrum analyzer, radio frequency signal generators and similar radio frequency equipment. The successful candidate will be experienced in reading circuit schematics, troubleshooting circuits and documenting test results. Also hand soldering and modification of surface and through-hole printed circuit boards (PCBs) is required. Direct experience in a production work environment required...

RCA Numitron Readout

RCA Numitron Readout, March 1970 Popular Electronics - RF CafeRCA's Numitron was their answer to the Nixie tube (manufactured by Burroughs Corporation). It was a simpler 7-segment incandescent display (DR2010) that, with all lines energized, formed the number 8. It worked off of +3.5 to +5 volts, with each element requiring 24 mA of current. The number 8 drew 192 mA of current and dissipated 0.672 W at 3.5 volts and a whopping 0.96 W at 5 volts! RCA marketed a BCD*-to-7-segment display driver (the CD2501E). The Numitron was pitched as a sensible alternative to the 7-segment LED display, but with an element size of 0.35" wide by 0.6" high, there was no real advantage over the LEDs, which were just entering the electronics market in 1970. Numitrons do have a certain nostalgic 'cool' factor, though. It is interesting to note that the author's last name, Wood, is the same as that of Frank Wood, who was issued...

Teledyne e2v HiRel and Integra Partner on High Voltage GaN Devices

Teledyne e2v HiRel and Integra Technologies Partner on High Voltage GaN Devices - RF CafeTeledyne e2v HiRel Electronics, a leading provider of high reliability semiconductor solutions, today announced a new high reliability partnership with California-based Integra Technologies, Inc. (Integra). Under the new agreement, Teledyne will leverage Integra's portfolio of GaN on SiC RF power transistor products to deliver optimized power solutions for the space market. With Integra, Teledyne e2v HiRel will specialize in providing high power RF devices for emerging space applications in the LEO and GEO payload market. Teledyne will also offer high reliability options for Integra's popular GaN on SiC power devices and pallets targeted at the defense market. "Our space customers are requesting RF power devices at higher power density levels and operating at higher frequencies," said Brad Little, VP and General Manager of Teledyne e2v HiRel. "The combination of our expertise in providing space...

Thanks to NextPCB for Continued Support!

NextPCB - RF CafeNextPCB is one of the most experienced PCB manufacturers in China, has specialized in the PCB and assembly industry for over 15 years. NextPCB provides the most innovative printed circuit boards and assembly technologies in the highest quality standards, turnaround time as fast as 24 hours, the lowest manufacturer direct prices, and the most dedicated customer service in the industry. Turnkey service without a broker including components sourcing, PCB prototyping, manufacturing, assembly, quality testing, and final shipment. Certified by IATF16949, ISO9001, ISO14001, UL, CQC, RoHS and REACH.

Tuesday the 2nd

War Bonds Promotion

War Bonds, January 1945, Radio-Craft - RF Cafe"The more things change, the more they remain the same." That old saw has held true throughout the ages, but there seems to be cycles within cycles that causes, to mix in a metaphor, the pendulum to swing back and forth in greater and lesser peak amplitudes, and over long periods of time a bias sets in that causes a perceivable change from the symmetric tick-tock-tick-tock-tick-tock, to tick----tock-tick----tock-tick----tock-tick. Without an outside-of-the-system input, the bias grows. If you have a "real" gravity-driven pendulum clock, you probably know what I mean. Bringing the system back to symmetry requires adjusting the clockworks movement or "righting" the physical orientation by rotating the clock on the wall or shimming up one side on the shelf until the preferred tick-tock-tick-tock is restored. Economic cycles are much the same, as alluded to in this World War II, War Bonds promotion. There are long periods of overall ups and overall downs, and in-between there are lesser rises and falls. Eventually, those who learn to control the cycles tend to insert a bias into the works...

3-D Diamond Valleytronic Transistor

3-D Diamond Valleytronic Transistor - RF Cafe"Researchers have, for the first time ever, demonstrated electrical control of valley transport in 3-D dual-gate diamond field-effect transistors. Not many people are aware of it, but the diamond is actually a wide-bandgap semiconductor with many extremely good properties, such as high thermal conductivity, high breakdown field, high carrier mobilities, and chemical inertness. These properties, together with the possibility to synthesize high-purity, single-crystalline diamond make it a very interesting material and a candidate for use4 in power electronics. The low impurity concentration achieved when fabricating diamond, together with its rigid lattice, causes it to exhibit a uniquely low scattering rate, especially at low temperatures..."

Behind the U.L. Label

Behind the U.L. Label, August 1955 Popular Electronics - RF CafeThe Underwriter's Laboratory (UL) is an entity that seems to have been around forever. A lot of people - maybe most people - assume that it is a government entity. In fact, it is a non-profit organization sponsored by the National Board of Fire Underwriters (later changed to American Insurance Association, then to APCIA). Its roots are traceable back to the Chicago World's Fair in 1893. Concern over the potential fire hazard of Edison's light bulbs was the impetus for the effort. Another aspect of the UL that a lot of people don't know is that the UL label of approval is no guarantee that the device works properly, only that is passes standards of safety as it relates to fire hazards. This article in the August 1955 edition of Popular Electronics magazine gives a brief history.

17 Best RTL-SDR Software Defined Radio Dongles

17 Best RTL-SDR Software Defined Radio Dongles - RF CafeRF Cafe visitor Tommy Reed sent me this link to a blog he recently posted on FromDCtoDaylight.com (great name) website entitled, "17 Best RTL-SDR Software Defined Radio Dongles." About six months ago I bought the Nooelec NESDR Smart v4 bundle to use with a modification I'm making to a couple vintage 72/75 MHz radio control systems. The 3rd-party interface and processing software is OK, but could be better. Otherwise, it works quite well. Says Tommy: "Software Defined Radios (SDRs) are become more and more popular. This is partially due to the wide availability of low cost USB dongle SDR radios based on RTL2832U demodulator chipset. This is where the 'RTL' in RTL-SDR comes from. While these low cost SDRs are not as capable as some of the higher performance SDR radios, they do offer a good bang for the buck. In this post we'll take a look at 17 great RTL-SDR dongles..."

Modelithics® Reaches Milestone of 20 Years!

Modelithics® Reaches Milestone of 20 Years in Establishment! - RF Cafe - RF CafeModelithics is honored to announce that it has crossed another milestone in the history of the company. As of March 1, 2021 Modelithics,, will be celebrating 20 years of establishment. What began as a small spinout startup from the University of South Florida has risen to stand tall as the industry leader in RF, microwave and millimeter-wave measurements and measurement-based modeling of RF and microwave components and semiconductor devices. We are proud of our company's many innovative products, custom service projects, designer focused application notes and other accomplishments that have proven to be exceptionally productive for our customers...

Get Your Custom-Designed RF Cafe Gear!

Custom-Designed RF-Themed Cups, T-Shirts, Mouse Pads, Clocks (Cafe Press) - RF CafeThis assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, and Baseball Caps. Choose from amazingly clever "We Are the World's Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow Chart." My "Matchmaker's" design has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. My markup is only a paltry 50¢ per item - Cafe Press gets the rest of your purchase price. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. It's a great way to help support RF Cafe. Thanks...

Thanks to Copper Mountain Technologies for Continued Support

Copper Mountain TechnologiesCopper Mountain Technologies develops innovative and robust RF test and measurement solutions for engineers all over the world. Copper Mountain's extensive line of unique form factor Vector Network Analyzers include an RF measurement module and a software application which runs on any Windows PC, laptop or tablet, connecting to the measurement hardware via USB interface. The result is a lower cost, faster, more effective test process that fits into the modern workspace in lab, production, field and secure testing environments.

Monday the 1st

Special Tubes by Sylvania

Special Tubes by Sylvania, January 1945, Radio-Craft - RF CafeWith most solid state devices, be they discrete elements or integrated circuits, discerning their functions by visual inspection is nearly always impossible. A trained observer can use a microscope on a bare die to get a good idea of what the various parts do. Memory banks, transistors, resistors, capacitors, etc., are usually pretty obvious even to someone relatively new at the job. Opaque overmolded packages and/or extremely small features complicate the task. In the vacuum tube days, anyone accustomed to working with them could fairly easily look at the the arrangement of heaters, cathodes, grids, and plates - sometimes singular but often multiple - and figure out the function. Experts could even make a fair guess at the key electrical specifications. Of course that only applied to those with clear glass envelopes. Tubes with special shapes might have been a bit more difficult to guess the application. To wit, the long, skinny R-1110 "Pirani Tube" shown here is an example. It is designed to measure ambient pressure...

Many Thanks to LadyBug Technologies for Their Continued Support!

LadyBug Technologies RF Power Sensors - RF CafeLadyBug Technologies was founded in 2004 by two microwave engineers with a passion for quality microwave test instrumentation. Our employees offer many years experience in the design and manufacture of the worlds best vector network analyzers, spectrum analyzers, power meters and associated components. The management team has additional experience in optical power testing, military radar and a variety of programming environments including LabVIEW, VEE and other languages often used in programmatic systems. Extensive experience in a broad spectrum of demanding measurement applications. You can be assured that our Power Sensors are designed, built, tested and calibrated without compromise.

NASA Helicopter Will Soon Fly on Mars

NASA Helicopter Will Soon Fly on Mars - RF Cafe"The Perseverance rover's Mars Helicopter (Ingenuity) will take off, navigate, and land on Mars without human intervention. Tucked under the belly of the Perseverance rover that will be landing on Mars in just a few days is a little helicopter called Ingenuity. Its body is the size of a box of tissues, slung underneath a pair of 1.2m carbon fiber rotors on top of four spindly legs. It weighs just 1.8kg, but the importance of its mission is massive. If everything goes according to plan, Ingenuity will become the first aircraft to fly on Mars. In order for this to work, Ingenuity has to survive frigid temperatures, manage merciless power constraints, and attempt a series of 90 second flights while separated from Earth by 10 light minutes. Which means that real-time communication..."

Understanding Transistor Circuits

Understanding Transistor Circuits, August 1959 Popular Electronics - RF CafeIt had been only a little over a decade since the transistor was invented when this article appeared in the August 1959 edition of Popular Electronics. Transistors were still a mystery to most people, including engineers, technicians, and hobbyists. Author James Butterfield takes a unique approach in presenting the material by writing it as a dialog between an instructor and a student. If you are also new to transistors, this will be worth your while to read. The basics will never change. As an aside (and mentioned in the article), while still a technician I had a manager one time who actually told an engineer working for him that a transistor could be made by soldering two diodes together and using the center node as the base connection...

KR Electronics Intros 1000 MHz Bandpass Filter

KR Electronics Intros 1000 MHz Connectorized Bandpass Filter - RF CafeKR Electronics, a designer and manufacturer of high quality filters for the commercial and military markets for more than 45 years, introduces the model 3450 lumped element bandpass filter with a 1,000 MHz center frequency and a 1 dB bandwidth of 50 MHz (~975 - 1025 MHz). The filter is a highly selective elliptic type filter. The filter is supplied either with SMA connectors (0.60" x 0.60" x 2.25" not including connectors) or in a surface mount package. Other frequencies and bandwidths are available...

Many Thanks to Atenlab for Their Continued Support!

Atenlab microwave components - RF CafeAtenlab has been operating in Taiwan for more than a decade, and has sold and installed hundreds chambers around the world. Holistic, affordable Over-the-Air (OTA) measurement systems perform comprehensive measurement and test in a controlled environment. Compact Antenna Test Range (CATR) with one-touch operation supports multiple systems - 2G, 3G, 4G, 5G - and major instrument brands. [M]ulti-probe OTA measurement systems offer reduced time measurements over single-probe systems.

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

2024:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2023:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2022:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2021:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2020:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2019:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2018:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2017:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

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

2012:  1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 (no archives before 2012)