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RF Cascade Workbook 2018 (GS) - RF Cafe

Tech Smorgasbord Archives - 35

A huge collection of my 'Factoids' can be accessed from my 'Kirt's Cogitations' table of contents.

Topical Smorgasbord, another manifestation of Factoids, are be found on these pages:

| 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 |

All pertain to topics that are related to the general engineering and science theme of RF Cafe.

Replacing the Dial Cord in a Realistic Patrolman-50 Radio

Replacing the Dial Cord in a Realistic Patrolman-50 Radio (Kirt's Cogitation #307) - RF CafeIn all my years of repairing and restoring old radios, I have never had the occasion to re-string a dial cord. There are many variations on dial cord construction and diameter, but there are even more variations in that way the path around the tuning shaft, tuning elements, and indicator dials are implemented. Larger radios with lots of room in them are relatively easy to re-string and usually take a fairly straightforward path, but smaller portable multiband radios like my 1970's-vintage Realistic Patrolman−50 are a bit of a challenge, as I found out recently. A Web search on recommendations for how to replace dial cords results mostly in frustrated handymen who have seemingly given up on the job. It is easy to understand why, especially on a ridiculously complicated routing scheme. My only guess as to the need for the multiple pulleys and specific number of wraps around each is because of the need to maintain very solid contact while tuning four separate variable capacitors ...

9/10/2018

Hearing Microwaves - It's All in Your Head

Microwave Weapon - Not Sonic - Might Have Caused Sickness at U.S. Embassy in Cuba - RF CafeLate in 2016, news outlets began reporting on American and Canadian diplomats stationed at their respective embassies in Cuba complaining of dizziness, nausea, headaches, ringing in the ears, and other seemingly sound-related illnesses. Similar reports have come out of China as well. At the time, doctors and scientists investigating the phenomenon thought maybe some sort of weaponized sonic beam was being directed at the personnel. Certain people were affected while others nearby experienced no such phenomena, leading researchers to believe that the presumably sonic beams were highly concentrated and directional. Some of the targeted personal were diagnosed as having suffered mild traumatic brain injury with likely damage to the central nervous system ...

9/4/2018

Insider $$$tock Trading at Your Company

Insider Stock Trading at Your Company (Kirt's Cogitation #305) - RF CafeIn 2010, I posted a short piece about where to look on the Web to learn what upper management, board members, and large investors were doing with insider company stock trades. At the time, the MSN Money website had a tool where you could enter a company's stock symbol and get a readout of who was buying and - more often that not - selling stock. That web page is gone, but I found the same information on InsiderCow.com. The dollar amounts are truly staggering to people like you (likely) and me (definitely). Numbers reported are sale values, not profit to the stock holder. Many of the stocks were issued as either grants or options, but even outright purchased stocks are included as well. Regardless, prepare to have your jaw drop if you have never seen this type of data before. Some of the more familiar technology companies have been selected for examples ...

7/10/2018

Open Radio Shack Sighted in Ashtabula, Ohio

Open Radio Shack Sighted in Ashtabula, Ohio (Kirt's Cogitation #304) - RF CafeWhile not quite the equivalent of an Elvis sighting, I was utterly surprised to see an open Radio Shack store in the Ashtabula Towne Square Mall during a recent trip to Ohio. As you can see in the photo, it is a shell of a store, with products on display only along the walls. Do you remember the days when every shopping mall and plaza had a Radio Shack crammed full of stereos, radios, calculators, antennas, computer accessories (and the TRS-80), toys, and of course a huge portion of the store dedicated to electronic project components? I had a "Battery Club" card for a couple decades, and a current catalog was always on my bookshelf. If, as the old saying goes, "Misery loves company," then the good folks at the Ashtabula Radio Shack can at least take some solace ...

6/25/2018

Sonic Booms, Fallout, Satellites, and the Moon

Sonic Booms, Fallout, Satellites, and the Moon (Kirt's Cogitation #303) - RF CafeThe Old Farmer's Almanac (OFA) has been on my annual need-to-buy list for as long as I can remember. It is chock full of useful data for sunrise and sunset times*, high and low tide times, crop planting days, first and last frost days, and significant astronomical events. There are stories of interest on topics ranging from canning your garden's harvest to how to view a solar eclipse. - often from noted authors, but also from lay people. I also enjoy the monthly "on this day" type tidbits and the homey short story relating to the time of year. After 225 years of continuous publication, it still features the hole in the upper left corner to facilitate handily hanging it on the wall of your shed -- or outhouse. I gave a 1961 edition of the Old Farmer's Almanac found on eBay to Melanie as a birthday present this year ...

5/15/2018

Found: Very Rare HP 5212A Electronic Counter

HP 5212A Electronic Counter (Kirt's Cogitation #301) - RF CafeThis rare HP 5212A Electronic Counter was found in a second-hand shop sitting in with a bunch of random electronic gear. The "HP" on the front panel piqued my attention, so I carried it to the counter and asked the nice lady to plug it in, figuring if the front panel lit up and none of the smoke that makes electronics work leaked out, I'd buy it. It did, it didn't, and I did, respectively. The outside condition is pretty good, with most of the scratches being on the top and bottom. Some oxidation is present on the bare aluminum chassis components, but a little ...

4/30/2018 

 

Vintage Alliance Model U-100 Tenna−Rotor

Vintage Alliance Model U-100 Tenna-Rotor Installation (Kirt's Cogitation #301) - RF CafeIf you grew up in the era of rooftop television antennas, then there is a good chance you are familiar with the electromechanical antenna pointing systems that were often installed as well. Alliance, Channel Master, Cornell Dubilier, Radio Shack, RCA, Winegard, and others made low cost, light-duty rotators for television antennas. Ham radio antenna rotators were/are more robust in order to handle higher weight and wind loads. Many television antennas also cover the FM radio band (88-108 MHz), allowing them to do double duty. Being an unapologetic technology renaissance man, I recently purchased (on eBay) a vintage Alliance Model U−100 Tenna−Rotor that was unused in the original ...

4/10/2018

Of Zerts, Plenches and Spunfits

Of Zerts, Plenches and Spunfits - RF CafeThe manned space program has unarguably provided mankind with many new and innovative tools, medicines, electronics, materials, physics, materials, appliances, and mathematics. Know officially as "spinoffs," products like the portable heart defibrillator unit, the portable vacuum cleaner, freeze-drying food processors, powdered lubricants, memory foam, quartz clocks and battery-powered tools. Many NASA inventions have not found an application in your basement or garage, however, because their purpose is too specialized. Take, for instance, the ZeRT, or Zero Reaction Tool ...

4/3/2018

World's 1st Radio Broadcast from Moving Train

World's 1st Radio Broadcast from a Moving Train - RF CafeYou might have noticed that since last November the engineering and science themed daily RF Cafe header images have been much larger than those which graced the pages in the past. The change was motivated mainly by a desire to make them more viewable on the tiny screens of mobile phones. It also gave me the opportunity to include more information. In the process, I took the occasion of being on each daily engineering and technology history page to check on the validity of the long ago included hyperlinks to pages which validated dates of events. Use Wikipedia was avoided because of the joke-worthy reputation it had for bogus ...

3/25/2018

Daylight Saving Time vs. Standard Time

Daylight Saving Time vs. Standard Time - RF CafeTo be or not to be - that is the question: Whether 'tis nobler in the mind to suffer the slings and arrows of outrageous bi-annual clock shifts, or to take up arms against a sea of contradicting justifications for and against its existence for DST, and by opposing, end it. Twice each year, a majority of the western world is subject to a manmade disruption in circadian and habitual cycles with an inane one-hour clock change on and off of "Daylight Saving(s) Time" (DST). Some historians claim that Benjamin Franklin joked about DST in the 18th century, but it was New Zealander George Hudson who proposed the modern day clock ...

3/12/2018

Amateur Radio Call Sign Grant Date Investigation

Amateur Radio Call Sign Grant Date Investigation - RF CafeHave you ever started a relatively simple investigation into a trivial matter, only to find yourself going down the metaphorical "rabbit hole" even after finding the original answer? Such was the case for me when someone sent me an e-mail with a signature that included his amateur radio call sign. The first three characters, KB3, matched mine and that got me wondering on what date his call sign was granted compared to mine. Let us say for example* the writer's call sign was KB3PGM and mine is (actually) KB3UON. I looked them up in the FCC's ULS self-serve license ...

2/14/2018

 

ESD Damage Control - It's Not Just for Semiconductors Anymore

ESD Damage Control - It's Not Just for Semiconductors Anymore - RF CafeIf, as the saying goes, "Misery loves company," then you will appreciate the following. Whilst perusing the December 2017 issue of NASA's Motion Design supplement to their Tech Briefs publication, I ran across the image to the right in an article titled, "Trends in Hydraulic Filtration" (areas of interest are quite diverse here at RF Cafe). After reading the caption stating that the holes were "fire holes," the first thing that came to mind was ESD damage. Sure enough, upon going back and reading more of the story (provided by Argo-Hytos), I found ...

12/5/2017

Farewell and Adieu, H. Ward Silver

Farewell and Adieu, H. Ward Silver - RF CafeAnother era, sadly, has come to an end. H. Ward Silver (aka Ward Silver, NØAX) has announced the end of his monthly column, "Hands-On Radio," in QST magazine. The title of each column was enumerated as "Experiment #nnn," followed by the subject. To wit, "Experiment #179 Maxwell's Equations - The Wave Emerges" is Mr. Silver's final column, appearing in the December 2017 QST. "Hands-On Radio" topics ranged in intensity from relatively simple discussion on calculating power dissipation in resistors, capacitors, and inductors to more heady treatises on subjects like electromagnetic fields within coaxial cable and waveguide to Maxwell's equations. Mathematics, too ...

11/27/2017

Edwin H. Armstrong: The Rest of the Story

Edwin H. Armstrong: The Rest of the Story - RF CafeOne of my favorite old-time radio personalities, Paul Harvey, had a trademarked feature titled The Rest of the Story. For those of you not familiar with the format, Mr. Harvey would begin his story talking about particular life aspects of a person that, while remarkable, usually had no connection with the person's eventual claim to fame. The listener's challenge was to guess who the person was before it was revealed at the very end, followed by, "... now you know --- the rest [emphasis] of the story." As far as I know the story of FM radio inventor Edwin H. Armstrong was never a subject, although it certainly met the criterion. I've already let the figurative cat out of the bag, so you already know my subject ...

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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About RF Cafe
Kirt Blattenberger - RF Cafe Webmaster
Copyright: 1996 - 2018
Webmaster:
    Kirt Blattenberger,
    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 ...

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