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Tech Smorgasbord Archives - 35

These items are an archive of past Topical Smorgasbord items that have appeared on the RF Cafe homepage. In keeping with the "cafe" genre, these tidbits of information are truly a smorgasbord of topics. They all pertain to topics that are related to the general engineering and science theme of RF Cafe. Note: There is also a huge collection of my 'Factoids' (aka 'Kirt's Cogitations') that might interest you as well.

| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 |

Boy Scouts of America's "Jamboree on the Air" 1958-2017

Boy Scouts of America's "Jamboree on the Air" 1958-2017, Kirt's Cogitations #293 - RF CafeFrom May 9th through the 11th in the year of our Lord 1958, the very first "Jamboree on the Air" (JOTA) was held by the Boy Scouts of America (BSA). The American Radio Relay League (ARRL), in conjunction with the BSA, is promoting this year's 60th anniversary event occurring from October 20-22. As you might imagine, quite a lot has changed over 59 years in terms of equipment, but the basics in terms of encouraging and assisting the next generation of licensed Hams remains as always the primary goal of organizers. The Boy Scouts, of course, join in for the fun and learning experience. Jamboree on the Air events, held in October, do not coincide with the National Scout Jamboree, held in July ...

10/9/2017

Nikola Tesla in 19th Century Newspapers, Kirt's Cogitations #292

Nikola Tesla in 19th Century Newspapers, Kirt's Cogitations #292 - RF CafeNikola Tesla was born in 1856 in Smiljan, Austrian Empire, and died in 1943 in New York City. His life is so amply documented far and wide that regurgitating the information in books and blog posts would be a waste. Most of what you find there is second-hand, having gone through the filter of an author's preferences. I like to search for stories on various topics in their original publications; e.g., scanned newspaper and magazine archives. A hunt for early stories on Nikola Tesla turned up many 19th century examples from the Newspapers.com website. It is interesting that back in the day, men like Nikola and Edison were referred regularly to as "electricians." The oldest article I found on Nikola Tesla appeared in the July 1, 1889 edition of The Pittsburgh Dispatch, titled "The Electric Fiend" ...

8/29/2017

The Great North American Solar Eclipse of 2017 - It's Here!

the Great North American Solar Eclipse of 2017, Kirt's Cogitation #291 - RF CafeIt's finally here - the Great North American Solar Eclipse of 2017! The amateur astronomy community has been anticipating and preparing for the event for a couple years. Astronomy magazine dedicated the entire August issue to providing detailed information on viewing suggestions along the entire path. Traffic from the Pacific Coast of Oregon to the Atlantic Coast of South Carolina will probably be a challenge as people vie for positions as close to the centerline as possible. Those who manage optimal locations will see about 2 minutes and 40 seconds of total darkness. Others within the 68-mile-wide path of totality will see from a fraction of a second up to the full extent. According to a calculator on the Vox website, we will only see a 76.2% eclipse, which will barely darken our skies ...

8/21/2017

1st Newspaper Article Re Invention of Transistor

1st Newspaper Appearance of Transistor Invention Announcement, Kirt's Cogitation #290 - RF CafeHmmm.... let us see what made the front page of the July 1, 1948 edition of Murray Hill, New Jersey's, The Madison Eagle newspaper: "Man Found Dead, Wedged in Drain on Park Edge," "Lawyer Fined $50 on Zone Charge," and Sandra Dean Stevenson had been born two weeks earlier. Oh, also included was "Invention Replaces Vacuum Tube" and "Local Man Invents New Device in Electronics for Bell Lab; Could Revolutionize Radio." Page 10 ran, "Bell Laboratory Releases Data on Newly Invented Transistor." It is widely known that Drs. Brattain, Shockley, and Bardeen formerly announced on December 23, 1947, within the walls of Bell Labs ...

8/18/2017

Breaking News: The Arctic Icebergs Are Melting - circa 1922!

Breaking News: The Arctic Icebergs Are Melting - circa 1922!, Kirt's Cogitation #289 - RF CafeWe have all been treated to a seemingly endless series of headlines portending rising ocean levels and the ensuing drowning of costal cities due to melting ice in the polar regions. This phenomenon ostensibly is brought on by the exponential increase in carbon emissions from developing third-world countries as well as established first-world countries in the post World War II era ... or was it post Vietnam, or maybe post Gulf War? The reference keeps changing, but it definitely began occurring since at least 1990, right? There is a problem, though. In the early and mid 1970s climate scientists began warning us of an approaching ...

8/9/2017

MIA: The Other Half of the Antenna and Cable Loss Equation

The Other Half of the Antenna and Cable Loss Equation, Kirt's Cogitation #288 - RF CafeFor some inexplicable reason, it seems that of the many articles I read dealing with antenna and feedline efficiencies, rarely is the receive side of the equation addressed. Yes, transmit power is expensive and there is a legitimate reason to reduce losses when converting power amplifier output to in-the-air power, especially for DX operations. However, it doesn't do much good to launch the full permissible 1,500 watts PEP and make a contact on the other side of the world if your system cannot receive a reply because of the excessive line loss and/or mismatch loss between your antenna and your receiver. Antennas and feedlines are reciprocal elements so if ...

7/26/2017

A Radio Shack Eulogy

A Radio Shack Eulogy - RF CafeFriends, former employees, and fellow lovers of all things electronic, we are gathered here today to remember and honor our lifelong friend and enabler of our hobby and passion, Radio Shack - once a Tandy company, as we are familiar with it. Radio Shack has lingered in failing health for a decade, all the time keeping a brave face on its dwindling number of stores. Caretakers attempted a variety of infusions and transplants in an attempt to save the American stalwart electronics retailer. Alas, a confluence of poor management ...

6/14/2017

1930 U.S. Census - Do You Own a Radio?

1930 U.S. Census - Do You Own a Radio?, Kirt's Cogitation #286 - RF CafeFor Mother's Day this year, the kids and I got Melanie a 23andMe DNA testing kit. She has spent a fair amount of time over the years researching the family lineage which, in case you care, traces back primarily to Germany and Switzerland. Along with some of the online ancestry websites, she searched the U.S. Census database for immigration and early American household information (number of people, ages, names, occupations, etc.) The entire 1930 Census form consisted of a single page seeking basic information on whether you own or rent, value of the home, live on a farm or not, color or race, ...

6/9/2017

Heathkit DX-60B Amateur Radio Transmitter Restoration

Heathkit DX-60B Amateur Radio Transmitter Restoration by Gary Steinhour, Kirt's Cogitation #285 - RF CafeLong-time RF Cafe visitor and occasional contributor Gary Steinhour, KF6U, recently sent me a note saying he had acquired a very used Heathkit DX-60B amateur radio transmitter and was in the process of restoring it. Gary's first transmitter as a freshly minted Ham over 50 years ago was a DX-60, so this was an effort to satisfy a nostalgic emotional attachment. The project is complete now, and boy does it look nice! Gary provides a brief account here ...

6/7/2017

Lightning Protection Systems

Lightning Protection Systems, Kirt's Cogitation #284 - RF CafeIf you have ever seen the result of a lightning strike on electronic equipment, then you know how devastating it can be - often total destruction that includes molten metal. Woe be unto any human operator who happens to be in contact with it at the time of the strike. Unprotected antennas are begging for contact. Shortly after leaving a company where I worked on a Tx/Rx system for a phased array weather radar I got word that the indoor equipment rack took a major hit because the guy who maintained the site forgot to reconnect a lightning rod system cable after moving it during ...

6/1/2017

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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 ...

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