Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes Calculators Education Engineering Magazine Articles Engineering software RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising Magazine Sponsor RF Cafe RF Electronics Symbols for Visio RF Electronics Symbols for Office Word RF Electronics Stencils for Visio Sponsor Links Saturday Evening Post NEETS EW Radar Handbook Microwave Museum About RF Cafe Aegis Power Systems Anritsu Alliance Test Equipment Amplifier Solutions Anatech Electronics Axiom Test Equipment Berkeley Nucleonics Bittele Centric RF Conduct RF Copper Mountain Technologies Empower RF everything RF Exodus Advanced Communications Innovative Power Products ISOTEC KR Filters Lotus Systems PCB Directory Rigol RF Superstore San Francisco Circuits Reactel RFCT TotalTemp Technologies Triad RF Systems Windfreak Technologies Withwave LadyBug Technologies Wireless Telecom Group Sponsorship Rates RF Cafe Software Resources Vintage Magazines Thank you for visiting RF Cafe!
TotalTemp Technologies (Thermal Platforms) - RF Cafe

Jacob's Staff = Log Periodic Antenna?
- RF Cafe Cool Pic -

Cool Pic Archive 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 |

These images have been chosen for their uniqueness. Subject matter ranges from historic events, to really cool phenomena in science and engineering, to relevant place, to ingenious contraptions, to interesting products (which now has its own dedicated Featured Product category).

Jacob's Staff image from "Comets, Popular Culture, and the Birth of Modern Cosmology" - RF Cafe Cool PicAlmost exactly two years ago, I featured a quilt made by Sara Schechner that depicted the 26-inch Alvan Clark telescope. A couple months ago, she contacted me about having learned of its appearance on RF Cafe. As it turns out she is the curator of the Collection of Historical Scientific Instruments at Harvard University, and she holds a PhD from Harvard. She wrote a book in 1997 titled, "Comets, Popular Culture, and the Birth of Modern Cosmology." It includes an extensive collection of ancient drawings and etchings of astronomical events such as comets, meteors, super novae, and solar system conjunctions, as well as implications of such phenomena in significant world events. Astrologers made a pretty good living in the day by convincing rulers and potentates that they had privileged insight into the significance of such things.

   Comets, Popular Culture, and the Birth of Modern Cosmology - RF Cafe

Comets, Popular Culture, and the Birth of Modern Cosmology, by Sara Schechner Genuth

While reading it, I ran across this etching (right) depicting "Archimedes (c.250 BC) beholding both [planets and comet] in his Jacobs Staff." The first thing that struck me in the image is that the Jacob's Staff looks an awful lot like a log periodic dipole antenna. Compare the rendition to the folded structure shown in the image from a Wikipedia article (below left). The physical size suggests its use is designed for maybe the 900 MHz ISM band, or even higher bands. Could Archimedes actually be pointing a directional radio frequency antenna at the comet in an attempt to communicate with alien beings in a starship, rather than using it to determine the celestial coordinates of the object?

Log Periodic Antenna, Wikipedia - RF CafeLog Periodic Antenna

Jacob's Staff, Wikipedia - RF CafeJacob's Staff

According to Wikipedia's explanation of how the Jacob's Staff was used, "The navigator places one end of the main staff against his cheek just below his eye. He sights the horizon at the end of the Jacob's Staff Etching, the REST of the Story - RF Cafelower part of the transom (or through the hole in the brass fitting) (B), adjusting the cross arm on the main arm until he or she can sight the sun at the other end of the transom (C). The altitude can then be determined by reading the position of the transom on the scale on the main staff. This value was converted to an angular measurement by looking up the value in a table."

OK, you might conclude given the context of the drawing that Archimedes was doing just that. However, note that the bottom of the picture seems to be missing. Well, with a little sleuthing in Cyberspace, I was able unearth the rest of the original picture (right). It appears to support my theory - what do you think?


RF Cafe Cool Pic - This quilt, made by HAD (Historical Astronomy Division, of the American Astronomical Society) past chair Sara Schechner, is a copy of a well-known photograph of the 26-inch Alvan Clark telescope as first set up at the original USNO site in Foggy Bottom, c.1873. Simon Newcomb is at the eyepiece. Details of the quilt (size, length of time to make, where displayed, etc.) are hard to come by.



Posted April 26, 2012

Amplifier Solutions Corporation (ASC) - RF Cafe
Rigol DSG5000 Microwave Generator - RF Cafe
Axiom Test Equipment - RF Cafe
Anritsu Test Equipment - RF Cafe

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

These Are Available for Free


About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024


    Kirt Blattenberger,


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 World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website: