Search RFCafe.com                           
      More Than 17,000 Unique Pages
Please support me by ADVERTISING!
Serving a Pleasant Blend of Yesterday, Today, and Tomorrow™ Please Support My Advertisers!
   Formulas & Data
Electronics | RF
Mathematics
Mechanics | Physics
     AI-Generated
     Technical Data
Pioneers | Society
Companies | Parts
Principles | Assns


 About | Sitemap
Homepage Archive
        Resources
Articles, Forums Calculators, Radar
Magazines, Museum
Radio Service Data
Software, Videos
     Entertainment
Crosswords, Humor Cogitations, Podcast
Quotes, Quizzes
   Parts & Services
1000s of Listings
 Vintage Magazines
Electronics World
Popular Electronics
Radio & TV News
QST | Pop Science
Popular Mechanics
Radio-Craft
Radio-Electronics
Short Wave Craft
Electronics | OFA
Saturday Eve Post

Software: RF Cascade Workbook
RF Stencils Visio | RF Symbols Visio
RF Symbols Office | Cafe Press
Espresso Engineering Workbook

Aegis Power  |  Alliance Test
Centric RF  |  Empower RF
ISOTEC  |  Reactel  |  RFCT
San Fran Circuits

Crane Aerospace Electronics Microwave Solutions

Noisecom

Anritsu Test Equipment - RF Cafe

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

RF Cascade Workbook for Excel

RF & Electronics Symbols for Visio

RF & Electronics Symbols for Office

RF & Electronics Stencils for Visio

RF Workbench

T-Shirts, Mugs, Cups, Ball Caps, Mouse Pads

These Are Available for Free

Espresso Engineering Workbook™

Smith Chart™ for Excel

Innovative Power Products Cool Chip Thermal Dissipation

Aircraft Detection Prior to the Invention of Radar
- 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).

Beginning in the middle of the 1930s, engineering labs in the U.S. and Europe were experimenting with radar systems. Early radars did not have the slick plan position indicator (PPI) displays that modern systems use for plotting target movement for indication of azimuth (direction) and range (distance). Instead, oscilloscopes showed radar returns as amplitude blips along a time base that represented range. Azimuth was determined by where the operator pointed the antenna (rotating versions came later). Since radar cross section stealth technology had not been invented yet, the amplitude of the signal was useful a measure of the size of the target.

Prior to the invention of radar (RAdio Detection And Ranging), other means were needed to detect approaching aircraft during times of war. Human spotters were often posted in open fields, tall building rooftops, shorelines, and hills in order to provide a measure of warning against approaching enemy aircraft (acoustic defense). Effectiveness was dependent on many parameters like quality of eyesight, hearing and alertness of the observers, atmosphere transparency (visibility), light level, aircraft size, configuration, color and noise level, etc. Even under ideal conditions detected aircraft would be no more than a few minutes away from the observer, so that did not leave a lot of time to prepare a response. Observer networks were set up as far in advance of key targets as possible through a radio relay network, but it left a lot to be desired.

That's where the strange, often Dr. Seuss-looking listening devices shown below were designed and employed to aid the observers. These photos are all over the Internet, so I do not know their origins. I will be glad to credit the true owner(s) if contacted, and will provide a hyperlink to the originals. Thanks to Bob D. for letting me know about them.

RF Cafe Cool Pic - Aircraft Detection Prior to Radar, Compliments of Dr. Seuss

Compliments of Dr. Seuss

RF Cafe Cool Pic - Aircraft Detection Prior to Radar, Didn't I see an ad for this in the back of Popular Science?

Didn't I see an ad for this in the back of Popular Science?

RF Cafe Cool Pic - Aircraft Detection Prior to Radar, An alt-az mount - impressive!

An alt-az mount - impressive!

RF Cafe Cool Pic - Aircraft Detection Prior to Radar, Modified cheerleader megaphones

Modified cheerleader megaphones

RF Cafe Cool Pic - Aircraft Detection Prior to Radar, Also useful for listening to avian mating rituals

Also useful for listening to avian mating rituals

RF Cafe Cool Pic - Aircraft Detection Prior to Radar, OK, this one has to be a joke

OK, this one has to be a joke

RF Cafe Cool Pic - Aircraft Detection Prior to Radar, Dr. Seuss again

Dr. Seuss again

RF Cafe Cool Pic - Aircraft Detection Prior to Radar, This concept was later used as an inspiration for the Ferris wheel

This concept was later used as an inspiration for the Ferris wheel

RF Cafe Cool Pic - Aircraft Detection Prior to Radar, Auchtung! Wir hören können alles, was sie sagen.

Achtung! Wir hören können alles, was sie sagen.

The douglas-self.com web page link was sent to me after posting these pictures. It has more information on these pictures. You'll probably enjoy perusing some of the other topics he has as well.

Here is a page on early radar development.

See the Homemade Plane Detector article from the May 1942 Popular Science magazine.

 

 

Posted March 29, 2019

Innovative Power Products Cool Chip Thermal Dissipation
KR Electronics (RF Filters) - RF Cafe



Innovative Power Products Cool Chip Thermal Dissipation - RF Cafe