ON the ULTRA HIGHS- a History of Amateur Radio VHF Activities

Total Page:16

File Type:pdf, Size:1020Kb

ON the ULTRA HIGHS- a History of Amateur Radio VHF Activities VHF HISTORICAL NOTES (Working Title) ON THE ULTRA HIGHS - A History of Amateur Radio VHF Activities - (Formal Title) Kevin Kaufhold, W9GKA Most Recent Update 12-2008 COPYRIGHT Copyright by Kevin C. Kaufhold. All rights reserved. Except as permitted under the United States Copyright Act, no part of this publication may be reproduced or distributed in any form or by any means, without the prior written permission of Kevin C. Kaufhold. The material contained herein may be referenced and cited to in other publications, provided proper credit is given. Many of the figures and diagrams contained in this are the copyright of the American Radio Relay League (ARRL), and have been reprinted with permission of the ARRL. The figures cannot be reproduced or distributed in any form or by any means, without the prior written permission of the ARRL. 2 TABLE OF CONTENTS ON THE ULTRA HIGHS .................................................................................................. 1 COPYRIGHT.................................................................................................................. 2 TABLE OF CONTENTS................................................................................................ 3 PREFACE....................................................................................................................... 4 Chapter 1 - A Scientific Inquiry of Electricity................................................................ 5 Chapter 2 – The Birth of Wireless ................................................................................ 18 Chapter 3 - The Law Arrives ........................................................................................ 38 Chapter 4 - The Beginnings of U.H.F........................................................................... 51 Chapter 5 - Three New Bands....................................................................................... 62 Chapter 6 – Exploration of UHF Propagation .............................................................. 70 Amateurs in WWII........................................................................................................ 82 Post WWII Amateur Activity & The Cold War ........................................................... 82 From Sputnik to the Early 1980’s................................................................................. 88 The Era of the Grid Squares.......................................................................................... 97 The No-Code Tech Explosion .................................................................................... 102 The Present and Future of VHF Activity.................................................................... 106 A Few Notes on International VHF Contests ............................................................. 108 3 PREFACE The material presented in this text has taken on a life of its own. It started as a bullet- point, outline type of supplement to the VHF Contest Records that I had put together for the Society of Midwest Contesters. It was thought that the VHF Contest Records should be kept in an historical perspective, with particular reference to major changes in the VHF contest rules. From there, this document then gradually moved to a historical review of all VHF activity on the amateur bands, and began to be known as the “VHF Historical Notes”. Pictures were added along the way, and the outline format was changed to regular text. Intensive research was also done on the explanatory factors for VHF contest log variations, resulting in the publication of several articles on the topic. Most recently, the material has been broken up into chapters, so that it can be more easily handled and downloaded from the SMC web-site. In its current format, the quality of the material has been so upgraded in terms of regular text, pictures, extensive footnotes, and references, that I have developed a more formal title to the document. While the “VHF Historical Notes” is still an apt description of the document on a working basis, I am currently referring to the text formally as: “On the Ultra-Highs - a History of Amateur Radio VHF Activities”. This formal title is in honor of the early VHF experimenters and the original VHF column in QST that started in December 1939. Every effort has been made to be as historically accurate and thorough as possible. Every VHF historical reference available from the American Radio Relay League has been reviewed, including all QST’s back to 1922, and several books relevant to VHF amateur radio activities. Various VHF conference proceedings of the regional amateur radio societies, ARRL Handbooks, VHF manuals of both the ARRL and the RSGB, FCC Rules and Regulations, and Federal Law pertinent to amateur radio have also been reviewed. The first few chapters are available on-line by clicking on the hyperlink in the Table of Contests. The bulk of material is still in outline form, and can also be accessed by clicking the hyperlink “Outline of Remaining Material, 1930’s to present”. Please note that I have taken many pictures from either QST or other ARRL publications, with permission from the League. In using the pictures, I have retained the text box describing the picture in the original article. Original text boxes nicely convey the manner in which pictures were initially presented in the articles, so efforts have been taken to copy the text messages as well as the original pictures. 4 Chapter 1 - A Scientific Inquiry of Electricity Before there could be radio, there had to be electricity. A very brief summary of the great milestones towards the full development of electrical phenomenon is therefore in order. The Greeks initially discovered electricity almost 2500 years ago when Thales of Miletus noticed that amber attracted small objects when rubbed with fur or silk. The Greeks called amber “electron”, and the word “electric” was described as “being like amber”, or having the ability to attract other objects. 1 While Thales had inadvertently stumbled upon static electricity, he and other Greeks of the era believed that certain inanimate substances, such as magnetized rock and amber, possessed a psyche, or soul, that was responsible for attraction of objects. Many centuries elapsed before this “soul” would be identified as static electricity and magnetism. 2 While the Greeks were describing a psyche to electrical phenomenon, the ability of the ancients to communicate long distances involved much more traditional methods. The Bible (Jeremiah 6:1) notes that signal flares were used around Bethlehem. In 522 BC, the Persian army used a relay message system by shouting from hilltops. A few years’ later, Athenian runners sent messages between battlefields. The great lighthouse at Alexander used a reflecting mirror of burnished metal. Mirrors were also employed to signal messages across distances – using what was known as a heliograph. Beacon fires were used in 427 BC to warn a military fleet of Spartan vessels that Athenian triremes were heading towards them and preparing to attack. Beacon fires were also noted in Homer’s Iliad. Rudimentary forms of optical telegraphs and “torch” telegraphy used in and around Greece for similar military activities were in existence by 150 to 360 BC. Roman Legions may have used signal beacons around 113 AD. Lantern- carrying kites were used in 500 AD as communication devices during the siege of Nanking, China. On the North American continent, Mississippian Indians built signal mounds around 1100 AD to communicate to their central cities, such as the massive urban complex at Cahokia, as well as at other locations. 3 Back on the Asian continent, Genghis Khan in 1206 used horse or pony stations spaced 25 miles apart to send messages across his vast empire. In 1588, beacon fires were used to mobilize the English against the Spanish Armada. Scientific study into the properties of electricity began in 1600 when William Gilbert, a physician to the royalty of England, published the first treatise on electrical and magnetic properties. 4 Gilbert had read the observations of Thales, and began experimenting with the attraction and repulsion of non-metallic rods. Gilbert coined the term “electricity” from these experiments. He may have been the first person to suggest a connection between static electricity and magnetism. A century later, Sir Isaac Newton penned his famous “Optics”, in which he set forth his theory of light. Newton thought that light involved wave-like behavior that could cause vibrations in “ether”. Newton’s work was the beginning of numerous studies on the properties of light. During the 1700’s, several observations piqued the curiosities of scientifically inclined minds. Iron-laden rock known as lodestone could make a magnetic compass needle move. Two metal plates placed in an acid solution could heat up a wire connected to the plates, and a nearby compass needle would swing back and forth. Some people felt that electricity and magnetism had to therefore be related in some manner. Then, in a simple but ultimately very important discovery, it was found in 1729 that that static electricity could be stored for later use and experimentation in what were known as Leyden jars. These jars were simply glass containers filled with water charged by a source of friction. The word “Leyden” generally came from the University of Leiden, where the discovery occurred. 5 Benjamin Franklin, experimented with Leyden jars, and made several contributions to science in the process. In 1748, Franklin
Recommended publications
  • The Army Amateur Radio System: 1925-1941
    The Army Amateur Radio System: 1925-1941 A Monograph by Major Scott B. Hedberg United States Army School of Advanced Military Studies United States Army Command and General Staff College Fort Leavenworth, Kansas AY 2010 Approved for Public Release; Distribution is Unlimited SCHOOL OF ADVANCED MILITARY STUDIES MONOGRAPH APPROVAL Major Scott B. Hedberg Title of Monograph: The Army Amateur Radio System: 1925-1941 Approved by: __________________________________ Monograph Director Dan Fullerton, Ph.D. __________________________________ Monograph Reader Michael A. Hochwart, Col., German Army ___________________________________ Director, Stefan Banach, CL, IN School of Advanced Military Studies ___________________________________ Director, Robert F. Baumann, Ph.D. Graduate Degree Programs Disclaimer: Opinions, conclusions, and recommendations expressed or implied within are solely those of the author, and do not represent the views of the US Army School of Advanced Military Studies, the US Army Command and General Staff College, the United States Army, the Department of Defense, or any other US government agency. Cleared for public release: distribution unlimited. 1 Abstract THE ARMY AMATEUR RADIO SYSTEM: 1925-1941 by MAJOR Scott B. Hedberg, United States Army, 78 pages. This monograph conducts a historical study of the Army Amateur Radio System, the predecessor to the Military Auxiliary Radio System (MARS). MARS is primarily known for its performance during the Vietnam conflict in providing morale communications for US service personnel. In 2009, the Department of Defense changed the MARS mission to support homeland security functions by using MARS to provide backup emergency communications to local, state, and federal authorities. Viewed as a new direction for MARS, the responsibility of providing emergency communications is the same mission that was ably conducted by the Army Amateur Radio System prior to the United States entry into World War II.
    [Show full text]
  • THE CABLE THAT WIRED the WORLD 41 the CABLE THAT WIRED the WORLD Today We Take Global Attractive Proposition to the Cotton Communications for Granted
    INFORM NETWORK DEVELOP NIGEL LINGE, BILL BURNS THE CABLE THAT WIRED THE WORLD 41 THE CABLE THAT WIRED THE WORLD Today we take global attractive proposition to the cotton communications for granted. NIGEL LINGE, merchants and growers. However, it was an American, Cyrus Field (see Figure 1), who on Whether telephoning someone in BILL BURNS 6 November 1856 established the Atlantic America, sending emails to Telegraph Company and sought to raise Australia or simply browsing the Xxxx xxxx xxxx £350,000 to manufacture and lay a web, we accept that our global telegraph cable between Britain and North America. To appreciate the scale of what telecommunications networks was being proposed, 1,600 nautical miles of will make it all happen. cable would be required to cross the Atlantic Nevertheless, life hasn’t always at its shortest width between the west coast been this convenient and this of Ireland and the east coast of Newfoundland, Canada. The longest year we are celebrating the 150th successful undersea cable that had been anniversary of a significant event constructed up until that time was a mere that proved to be the catalyst for 300 miles in length under the Black Sea, linking the Crimea to Varna on the Bulgarian a telecommunications revolution coast. that laid the foundations of the global connectivity that we all Nevertheless, the Victorian can-do attitude enjoy today – the first fully- prevailed and on 31 July 1857, HMS Agamemnon and USA Niagara set sail from operational telecommunications Figure 1: Cyrus Field (1819-1892), Pioneer of the Valentia in Ireland and headed west towards cable to be laid under the Trans-Atlantic Telegraph Trinity Bay in Newfoundland.
    [Show full text]
  • Army Radio Communication in the Great War Keith R Thrower, OBE
    Army radio communication in the Great War Keith R Thrower, OBE Introduction Prior to the outbreak of WW1 in August 1914 many of the techniques to be used in later years for radio communications had already been invented, although most were still at an early stage of practical application. Radio transmitters at that time were predominantly using spark discharge from a high voltage induction coil, which created a series of damped oscillations in an associated tuned circuit at the rate of the spark discharge. The transmitted signal was noisy and rich in harmonics and spread widely over the radio spectrum. The ideal transmission was a continuous wave (CW) and there were three methods for producing this: 1. From an HF alternator, the practical design of which was made by the US General Electric engineer Ernst Alexanderson, initially based on a specification by Reginald Fessenden. These alternators were primarily intended for high-power, long-wave transmission and not suitable for use on the battlefield. 2. Arc generator, the practical form of which was invented by Valdemar Poulsen in 1902. Again the transmitters were high power and not suitable for battlefield use. 3. Valve oscillator, which was invented by the German engineer, Alexander Meissner, and patented in April 1913. Several important circuits using valves had been produced by 1914. These include: (a) the heterodyne, an oscillator circuit used to mix with an incoming continuous wave signal and beat it down to an audible note; (b) the detector, to extract the audio signal from the high frequency carrier; (c) the amplifier, both for the incoming high frequency signal and the detected audio or the beat signal from the heterodyne receiver; (d) regenerative feedback from the output of the detector or RF amplifier to its input, which had the effect of sharpening the tuning and increasing the amplification.
    [Show full text]
  • Radio Communications in the Digital Age
    Radio Communications In the Digital Age Volume 1 HF TECHNOLOGY Edition 2 First Edition: September 1996 Second Edition: October 2005 © Harris Corporation 2005 All rights reserved Library of Congress Catalog Card Number: 96-94476 Harris Corporation, RF Communications Division Radio Communications in the Digital Age Volume One: HF Technology, Edition 2 Printed in USA © 10/05 R.O. 10K B1006A All Harris RF Communications products and systems included herein are registered trademarks of the Harris Corporation. TABLE OF CONTENTS INTRODUCTION...............................................................................1 CHAPTER 1 PRINCIPLES OF RADIO COMMUNICATIONS .....................................6 CHAPTER 2 THE IONOSPHERE AND HF RADIO PROPAGATION..........................16 CHAPTER 3 ELEMENTS IN AN HF RADIO ..........................................................24 CHAPTER 4 NOISE AND INTERFERENCE............................................................36 CHAPTER 5 HF MODEMS .................................................................................40 CHAPTER 6 AUTOMATIC LINK ESTABLISHMENT (ALE) TECHNOLOGY...............48 CHAPTER 7 DIGITAL VOICE ..............................................................................55 CHAPTER 8 DATA SYSTEMS .............................................................................59 CHAPTER 9 SECURING COMMUNICATIONS.....................................................71 CHAPTER 10 FUTURE DIRECTIONS .....................................................................77 APPENDIX A STANDARDS
    [Show full text]
  • Electret Microphone Replacement for a Carbon Insert
    The VMARS Newsletter Issue 29 Electret microphone replacement for a carbon insert Colin Guy G4DDI When I found that I had a dud carbon insert in an H33F/PT handset, and I couldn’t find another insert that fitted (the original is about 1” diameter) I looked around for an alternative. Trevor Sanderson’s excellent article “The RAF Microphone” (Radio Bygones issue 79/80) makes reference to the use of electret inserts with an IC preamplifier in telephones and aircraft headsets, but the information given was too scant to make construction of one of these possible without reference to the IC data sheet, and the IC’s are expensive and difficult to obtain. I had a GPO type 21A insert, but the innards of this when dismantled were still too large to fit into the available space. The H33 handset is very slim, and also virtually solid, so there is very little room in which to place a preamplifier. A dig around on the internet turned up the following article written by F. Hueber, originally published in Elektor Electronics December 1994, and is published here with permission from Elektor Electronics magazine, December 1994, copyright Segment B.V., Beek (Lb.), The Netherlands, www.segment.nl. The original article included a pcb layout, but I built mine on a strip of veroboard four tracks wide by about 2” (see photo) and mounted it on the back of the ptt switch. The electret insert was acquired from a scrap telephone and all the rest of the components from TV panels. To save space the rectifier and R12 weren’t included, care being taken to ensure that the polarity was correct.
    [Show full text]
  • The Stage Is Set
    The Stage Is Set: Developments before 1900 Leading to Practical Wireless Communication Darrel T. Emerson National Radio Astronomy Observatory1, 949 N. Cherry Avenue, Tucson, AZ 85721 In 1909, Guglielmo Marconi and Carl Ferdinand Braun were awarded the Nobel Prize in Physics "in recognition of their contributions to the development of wireless telegraphy." In the Nobel Prize Presentation Speech by the President of the Royal Swedish Academy of Sciences [1], tribute was first paid to the earlier theorists and experimentalists. “It was Faraday with his unique penetrating power of mind, who first suspected a close connection between the phenomena of light and electricity, and it was Maxwell who transformed his bold concepts and thoughts into mathematical language, and finally, it was Hertz who through his classical experiments showed that the new ideas as to the nature of electricity and light had a real basis in fact.” These and many other scientists set the stage for the rapid development of wireless communication starting in the last decade of the 19th century. I. INTRODUCTION A key factor in the development of wireless communication, as opposed to pure research into the science of electromagnetic waves and phenomena, was simply the motivation to make it work. More than anyone else, Marconi was to provide that. However, for the possibility of wireless communication to be treated as a serious possibility in the first place and for it to be able to develop, there had to be an adequate theoretical and technological background. Electromagnetic theory, itself based on earlier experiment and theory, had to be sufficiently developed that 1.
    [Show full text]
  • HELIOGRAPH DESCRIPTION: the Heliograph Was a Communications Device Used to Transmit Messages Over Long Distances. It Uses a Mi
    HELIOGRAPH DESCRIPTION: The heliograph was a communications device used to transmit messages over long distances. It uses a mirror attached to a surveying device to direct a beam of light to a receiving station. Sunlight is used as the light source. Messages could be sent in any direction during daylight hours. If the sun was in front of the sender, the sun’s rays were reflected directly from the sender to the receiving station. If the sun was behind the sender, a secondary mirror was used to reflect the rays toward the receiving station. A keying system was used to generate the flashes required to transmit messages using the Morse Code. The distance that the signals could be seen depended on several variables. A clear line of sight was required and Heliograph at Fort because of the curvature of the earth, the heliograph stations were Bowie Visitor Center located on the highest convenient point. The clarity of the sky and the size of the mirrors were also significant factors. The maximum range was about 10 miles for each inch of mirror diameter. Under normal conditions using the naked eye, a flash could be seen for about 30 miles, much farther using a telescope. The speed at which messages could be sent was dependent on the proficiency of both the sender and the receiver. EARLY HISYORY: A forerunner to the heliograph, the heliotrope, was developed by Professor Carl Friedrich Gauss of the University of Gottingen in Germany. The heliotrope was used to direct a controlled beam of sunlight to a distant station to be used as a survey marker.
    [Show full text]
  • Battle Management Language: History, Employment and NATO Technical Activities
    Battle Management Language: History, Employment and NATO Technical Activities Mr. Kevin Galvin Quintec Mountbatten House, Basing View, Basingstoke Hampshire, RG21 4HJ UNITED KINGDOM [email protected] ABSTRACT This paper is one of a coordinated set prepared for a NATO Modelling and Simulation Group Lecture Series in Command and Control – Simulation Interoperability (C2SIM). This paper provides an introduction to the concept and historical use and employment of Battle Management Language as they have developed, and the technical activities that were started to achieve interoperability between digitised command and control and simulation systems. 1.0 INTRODUCTION This paper provides a background to the historical employment and implementation of Battle Management Languages (BML) and the challenges that face the military forces today as they deploy digitised C2 systems and have increasingly used simulation tools to both stimulate the training of commanders and their staffs at all echelons of command. The specific areas covered within this section include the following: • The current problem space. • Historical background to the development and employment of Battle Management Languages (BML) as technology evolved to communicate within military organisations. • The challenges that NATO and nations face in C2SIM interoperation. • Strategy and Policy Statements on interoperability between C2 and simulation systems. • NATO technical activities that have been instigated to examine C2Sim interoperation. 2.0 CURRENT PROBLEM SPACE “Linking sensors, decision makers and weapon systems so that information can be translated into synchronised and overwhelming military effect at optimum tempo” (Lt Gen Sir Robert Fulton, Deputy Chief of Defence Staff, 29th May 2002) Although General Fulton made that statement in 2002 at a time when the concept of network enabled operations was being formulated by the UK and within other nations, the requirement remains extant.
    [Show full text]
  • History of Radio Broadcasting in Montana
    University of Montana ScholarWorks at University of Montana Graduate Student Theses, Dissertations, & Professional Papers Graduate School 1963 History of radio broadcasting in Montana Ron P. Richards The University of Montana Follow this and additional works at: https://scholarworks.umt.edu/etd Let us know how access to this document benefits ou.y Recommended Citation Richards, Ron P., "History of radio broadcasting in Montana" (1963). Graduate Student Theses, Dissertations, & Professional Papers. 5869. https://scholarworks.umt.edu/etd/5869 This Thesis is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. THE HISTORY OF RADIO BROADCASTING IN MONTANA ty RON P. RICHARDS B. A. in Journalism Montana State University, 1959 Presented in partial fulfillment of the requirements for the degree of Master of Arts in Journalism MONTANA STATE UNIVERSITY 1963 Approved by: Chairman, Board of Examiners Dean, Graduate School Date Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number; EP36670 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMT Oiuartation PVUithing UMI EP36670 Published by ProQuest LLC (2013).
    [Show full text]
  • The Beginner's Handbook of Amateur Radio
    FM_Laster 9/25/01 12:46 PM Page i THE BEGINNER’S HANDBOOK OF AMATEUR RADIO This page intentionally left blank. FM_Laster 9/25/01 12:46 PM Page iii THE BEGINNER’S HANDBOOK OF AMATEUR RADIO Clay Laster, W5ZPV FOURTH EDITION McGraw-Hill New York San Francisco Washington, D.C. Auckland Bogotá Caracas Lisbon London Madrid Mexico City Milan Montreal New Delhi San Juan Singapore Sydney Tokyo Toronto McGraw-Hill abc Copyright © 2001 by The McGraw-Hill Companies. All rights reserved. Manufactured in the United States of America. Except as per- mitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written permission of the publisher. 0-07-139550-4 The material in this eBook also appears in the print version of this title: 0-07-136187-1. All trademarks are trademarks of their respective owners. Rather than put a trademark symbol after every occurrence of a trade- marked name, we use names in an editorial fashion only, and to the benefit of the trademark owner, with no intention of infringe- ment of the trademark. Where such designations appear in this book, they have been printed with initial caps. McGraw-Hill eBooks are available at special quantity discounts to use as premiums and sales promotions, or for use in corporate training programs. For more information, please contact George Hoare, Special Sales, at [email protected] or (212) 904-4069. TERMS OF USE This is a copyrighted work and The McGraw-Hill Companies, Inc.
    [Show full text]
  • Alexander Graham Bell 1847-1922
    NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA BIOGRAPHICAL MEMOIRS VOLUME XXIII FIRST MEMOIR BIOGRAPHICAL MEMOIR OF ALEXANDER GRAHAM BELL 1847-1922 BY HAROLD S. OSBORNE PRESENTED TO THE ACADEMY AT THE ANNUAL MEETING, 1943 It was the intention that this Biographical Memoir would be written jointly by the present author and the late Dr. Bancroft Gherardi. The scope of the memoir and plan of work were laid out in cooperation with him, but Dr. Gherardi's untimely death prevented the proposed collaboration in writing the text. The author expresses his appreciation also of the help of members of the Bell family, particularly Dr. Gilbert Grosvenor, and of Mr. R. T. Barrett and Mr. A. M. Dowling of the American Telephone & Telegraph Company staff. The courtesy of these gentlemen has included, in addition to other help, making available to the author historic documents relating to the life of Alexander Graham Bell in the files of the National Geographic Society and in the Historical Museum of the American Telephone and Telegraph Company. ALEXANDER GRAHAM BELL 1847-1922 BY HAROLD S. OSBORNE Alexander Graham Bell—teacher, scientist, inventor, gentle- man—was one whose life was devoted to the benefit of mankind with unusual success. Known throughout the world as the inventor of the telephone, he made also other inventions and scientific discoveries of first importance, greatly advanced the methods and practices for teaching the deaf and came to be admired and loved throughout the world for his accuracy of thought and expression, his rigid code of honor, punctilious courtesy, and unfailing generosity in helping others.
    [Show full text]
  • The Early Years of the Telephone
    ©2012 JSR The early years of the telephone The early years of the telephone John S. Reid Before Bell Ask who invented the telephone and most people who have an answer will reply Alexander Graham Bell, and probably clock it up as yet another invention by a Scotsman that was commercialised beyond our borders. Like many one line summaries, this is partly true but it credits to one person much more than he really deserves. Bell didn’t invent the word, he didn’t invent the concept, what ever the patent courts decreed, and actually didn’t invent most of the technology needed to turn the telephone into a business or household reality. He did, though, submit a crucial patent at just the right time in 1876, find backers to develop his concept, promoted his invention vigorously and pursued others through the courts to establish close to a monopoly business that made him and a good many others very well off. So, what is the fuller story of the early years of the telephone? In the 1820s, Charles Wheatstone who would later make a big name for himself as an inventor of telegraphy equipment invented a device he called a ‘telephone’ for transmitting music from one room to the next. It was not electrical but relied on conducting sound through a rod. In the same decade he also invented a device he called a ‘microphone’, for listening to faint sounds, but again it was not electrical. In succeeding decades quite a number of different devices by various inventors were given the name ‘telephone’.
    [Show full text]