Voice Modulation - Revision history

Thomas: correct italized ship's name with possessive

2011-02-25T19:55:28Z

correct italized ship's name with possessive

← Older revision		Revision as of 19:55, 25 February 2011
Line 25:		Line 25:
	:The single audio amplifier stage in this transmitter was driven by audio from a carbon-type microphone, transformer-coupled to the audio tube control grid.<ref>[http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#6 Mike Everette, "A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020."]</ref>		:The single audio amplifier stage in this transmitter was driven by audio from a carbon-type microphone, transformer-coupled to the audio tube control grid.<ref>[http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#6 Mike Everette, "A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020."]</ref>

	One of the [[what went wrong\|breakdowns in communication]] between the ''[[Itasca]]'' and [[NR16020]] was due to the fact that ''Itasca's'' [[frequency\|high-frequency transmitter]] (the one used to transmit on 7500 kcs) was not equipped for voice modulation.<ref>[http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/traffic.html#628 6/28/37 from ''Itasca'':] "ITASCA TRANSMITTERS CALIBRATED 7500 6210 3105 500 AND 425 KCS CW AND LAST THREE EITHER CW OR MCW."</ref> The ''Itasca'' could only transmit using [[Morse Code]] transmitted via [[CW]] on 7500 kcs.<ref>[http://www.tighar.org/Publications/TTracks/12_2/logjam.html "Log Jam."]</ref> Tragically, this was the only frequency on which Earhart heard the ''Itasca's'' transmissions; if the ''Itasca'' could have transmitted to her in voice on this frequency, the problems with the [[direction finding]] might have been sorted out.		One of the [[what went wrong\|breakdowns in communication]] between the ''[[Itasca]]'' and [[NR16020]] was due to the fact that ''Itasca''’s [[frequency\|high-frequency transmitter]] (the one used to transmit on 7500 kcs) was not equipped for voice modulation.<ref>[http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/traffic.html#628 6/28/37 from ''Itasca'':] "ITASCA TRANSMITTERS CALIBRATED 7500 6210 3105 500 AND 425 KCS CW AND LAST THREE EITHER CW OR MCW."</ref> The ''Itasca'' could only transmit using [[Morse Code]] transmitted via [[CW]] on 7500 kcs.<ref>[http://www.tighar.org/Publications/TTracks/12_2/logjam.html "Log Jam."]</ref> Tragically, this was the only frequency on which Earhart heard the ''Itasca''’s transmissions; if the ''Itasca'' could have transmitted to her in voice on this frequency, the problems with the [[direction finding]] might have been sorted out.

	The ''[[Itasca]]'' was only prepared to transmit voice on 3105 kcs:		The ''[[Itasca]]'' was only prepared to transmit voice on 3105 kcs:

Thomas at 03:31, 23 February 2011

2011-02-23T03:31:37Z

← Older revision		Revision as of 03:31, 23 February 2011
Line 25:		Line 25:
	:The single audio amplifier stage in this transmitter was driven by audio from a carbon-type microphone, transformer-coupled to the audio tube control grid.<ref>[http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#6 Mike Everette, "A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020."]</ref>		:The single audio amplifier stage in this transmitter was driven by audio from a carbon-type microphone, transformer-coupled to the audio tube control grid.<ref>[http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#6 Mike Everette, "A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020."]</ref>

	One of the [[what went wrong\|breakdowns in communication]] between the ''[[Itasca]]'' and [[NR16020]] was due to the fact that ''Itasca'''s [[frequency\|high-frequency transmitter]] (the one used to transmit on 7500 kcs) was not equipped for voice modulation.<ref>[http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/traffic.html#628 6/28/37 from ''Itasca'':] "ITASCA TRANSMITTERS CALIBRATED 7500 6210 3105 500 AND 425 KCS CW AND LAST THREE EITHER CW OR MCW."</ref> The ''Itasca'' could only transmit using [[Morse Code]] transmitted via [[CW]] on 7500 kcs.<ref>[http://www.tighar.org/Publications/TTracks/12_2/logjam.html "Log Jam."]</ref> Tragically, this was the only frequency on which Earhart heard the ''Itasca'''s transmissions; if the ''Itasca'' could have transmitted to her in voice on this frequency, the problems with the [[direction finding]] might have been sorted out.		One of the [[what went wrong\|breakdowns in communication]] between the ''[[Itasca]]'' and [[NR16020]] was due to the fact that ''Itasca's'' [[frequency\|high-frequency transmitter]] (the one used to transmit on 7500 kcs) was not equipped for voice modulation.<ref>[http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/traffic.html#628 6/28/37 from ''Itasca'':] "ITASCA TRANSMITTERS CALIBRATED 7500 6210 3105 500 AND 425 KCS CW AND LAST THREE EITHER CW OR MCW."</ref> The ''Itasca'' could only transmit using [[Morse Code]] transmitted via [[CW]] on 7500 kcs.<ref>[http://www.tighar.org/Publications/TTracks/12_2/logjam.html "Log Jam."]</ref> Tragically, this was the only frequency on which Earhart heard the ''Itasca's'' transmissions; if the ''Itasca'' could have transmitted to her in voice on this frequency, the problems with the [[direction finding]] might have been sorted out.

	The ''[[Itasca]]'' was only prepared to transmit voice on 3105 kcs:		The ''[[Itasca]]'' was only prepared to transmit voice on 3105 kcs:

Thomas: italicize ship's name

2011-02-23T03:30:15Z

italicize ship's name

← Older revision		Revision as of 03:30, 23 February 2011
Line 25:		Line 25:
	:The single audio amplifier stage in this transmitter was driven by audio from a carbon-type microphone, transformer-coupled to the audio tube control grid.<ref>[http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#6 Mike Everette, "A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020."]</ref>		:The single audio amplifier stage in this transmitter was driven by audio from a carbon-type microphone, transformer-coupled to the audio tube control grid.<ref>[http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#6 Mike Everette, "A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020."]</ref>

	One of the [[what went wrong\|breakdowns in communication]] between the [[Itasca]] and [[NR16020]] was due to the fact that Itasca's [[frequency\|high-frequency transmitter]] (the one used to transmit on 7500 kcs) was not equipped for voice modulation.<ref>[http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/traffic.html#628 6/28/37 from Itasca:] "ITASCA TRANSMITTERS CALIBRATED 7500 6210 3105 500 AND 425 KCS CW AND LAST THREE EITHER CW OR MCW."</ref> The Itasca could only transmit using [[Morse Code]] transmitted via [[CW]] on 7500 kcs.<ref>[http://www.tighar.org/Publications/TTracks/12_2/logjam.html "Log Jam."]</ref> Tragically, this was the only frequency on which Earhart heard the Itasca's transmissions; if the Itasca could have transmitted to her in voice on this frequency, the problems with the [[direction finding]] might have been sorted out.		One of the [[what went wrong\|breakdowns in communication]] between the ''[[Itasca]]'' and [[NR16020]] was due to the fact that ''Itasca'''s [[frequency\|high-frequency transmitter]] (the one used to transmit on 7500 kcs) was not equipped for voice modulation.<ref>[http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/traffic.html#628 6/28/37 from ''Itasca'':] "ITASCA TRANSMITTERS CALIBRATED 7500 6210 3105 500 AND 425 KCS CW AND LAST THREE EITHER CW OR MCW."</ref> The ''Itasca'' could only transmit using [[Morse Code]] transmitted via [[CW]] on 7500 kcs.<ref>[http://www.tighar.org/Publications/TTracks/12_2/logjam.html "Log Jam."]</ref> Tragically, this was the only frequency on which Earhart heard the ''Itasca'''s transmissions; if the ''Itasca'' could have transmitted to her in voice on this frequency, the problems with the [[direction finding]] might have been sorted out.

	The [[Itasca]] was only prepared to transmit voice on 3105 kcs:		The ''[[Itasca]]'' was only prepared to transmit voice on 3105 kcs:

	:ALL COMMUNICATION FROM PLANE WILL BE ON 500, 3105 OR 6210 KILOCYCLES BY VOICE, POSITIONS BEING GIVEN AT FIFTEEN AND FORTY FIVE MINUTES PAST THE HOUR. ITASCA ADJUST TRANSMITTER FOR POSSIBLE USE 3105 KILOCYCLES FOR VOICE.<ref>[http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/traffic.html#625 "Radio Traffic," 6/25/37.]</ref>		:ALL COMMUNICATION FROM PLANE WILL BE ON 500, 3105 OR 6210 KILOCYCLES BY VOICE, POSITIONS BEING GIVEN AT FIFTEEN AND FORTY FIVE MINUTES PAST THE HOUR. ITASCA ADJUST TRANSMITTER FOR POSSIBLE USE 3105 KILOCYCLES FOR VOICE.<ref>[http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/traffic.html#625 "Radio Traffic," 6/25/37.]</ref>

Thomas: correct TTracks URL

2011-02-23T03:28:26Z

correct TTracks URL

← Older revision		Revision as of 03:28, 23 February 2011
Line 25:		Line 25:
	:The single audio amplifier stage in this transmitter was driven by audio from a carbon-type microphone, transformer-coupled to the audio tube control grid.<ref>[http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#6 Mike Everette, "A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020."]</ref>		:The single audio amplifier stage in this transmitter was driven by audio from a carbon-type microphone, transformer-coupled to the audio tube control grid.<ref>[http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#6 Mike Everette, "A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020."]</ref>

	One of the [[what went wrong\|breakdowns in communication]] between the [[Itasca]] and [[NR16020]] was due to the fact that Itasca's [[frequency\|high-frequency transmitter]] (the one used to transmit on 7500 kcs) was not equipped for voice modulation.<ref>[http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/traffic.html#628 6/28/37 from Itasca:] "ITASCA TRANSMITTERS CALIBRATED 7500 6210 3105 500 AND 425 KCS CW AND LAST THREE EITHER CW OR MCW."</ref> The Itasca could only transmit using [[Morse Code]] transmitted via [[CW]] on 7500 kcs.<ref>[http://www.tighar.org/TTracks/12_2/logjam.html "Log Jam."]</ref> Tragically, this was the only frequency on which Earhart heard the Itasca's transmissions; if the Itasca could have transmitted to her in voice on this frequency, the problems with the [[direction finding]] might have been sorted out.		One of the [[what went wrong\|breakdowns in communication]] between the [[Itasca]] and [[NR16020]] was due to the fact that Itasca's [[frequency\|high-frequency transmitter]] (the one used to transmit on 7500 kcs) was not equipped for voice modulation.<ref>[http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/traffic.html#628 6/28/37 from Itasca:] "ITASCA TRANSMITTERS CALIBRATED 7500 6210 3105 500 AND 425 KCS CW AND LAST THREE EITHER CW OR MCW."</ref> The Itasca could only transmit using [[Morse Code]] transmitted via [[CW]] on 7500 kcs.<ref>[http://www.tighar.org/Publications/TTracks/12_2/logjam.html "Log Jam."]</ref> Tragically, this was the only frequency on which Earhart heard the Itasca's transmissions; if the Itasca could have transmitted to her in voice on this frequency, the problems with the [[direction finding]] might have been sorted out.

	The [[Itasca]] was only prepared to transmit voice on 3105 kcs:		The [[Itasca]] was only prepared to transmit voice on 3105 kcs:

Moleski at 22:52, 12 October 2009

2009-10-12T22:52:17Z

← Older revision		Revision as of 22:52, 12 October 2009
Line 25:		Line 25:
	:The single audio amplifier stage in this transmitter was driven by audio from a carbon-type microphone, transformer-coupled to the audio tube control grid.<ref>[http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#6 Mike Everette, "A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020."]</ref>		:The single audio amplifier stage in this transmitter was driven by audio from a carbon-type microphone, transformer-coupled to the audio tube control grid.<ref>[http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#6 Mike Everette, "A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020."]</ref>

	One of the [[what went wrong\|breakdowns in communication]] between the [[Itasca]] and [[NR16020]] was due to the fact that Itasca's [[frequency\|high-frequency transmitter]] (the one used to transmit on 7500 kcs) was not equipped ~~with a microphone and~~ voice modulation.<ref>[http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/traffic.html#628 6/28/37 from Itasca:] "ITASCA TRANSMITTERS CALIBRATED 7500 6210 3105 500 AND 425 KCS CW AND LAST THREE EITHER CW OR MCW."</ref> The Itasca could only transmit using [[Morse Code]] transmitted via [[CW]] on ~~that frequency~~.<ref>[http://www.tighar.org/TTracks/12_2/logjam.html "Log Jam."]</ref> Tragically, this was the only frequency on which Earhart heard the Itasca's transmissions; if the Itasca could have transmitted to her in voice on this frequency, the problems with the [[direction finding]] might have been sorted out.		One of the [[what went wrong\|breakdowns in communication]] between the [[Itasca]] and [[NR16020]] was due to the fact that Itasca's [[frequency\|high-frequency transmitter]] (the one used to transmit on 7500 kcs) was not equipped for voice modulation.<ref>[http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/traffic.html#628 6/28/37 from Itasca:] "ITASCA TRANSMITTERS CALIBRATED 7500 6210 3105 500 AND 425 KCS CW AND LAST THREE EITHER CW OR MCW."</ref> The Itasca could only transmit using [[Morse Code]] transmitted via [[CW]] on 7500 kcs.<ref>[http://www.tighar.org/TTracks/12_2/logjam.html "Log Jam."]</ref> Tragically, this was the only frequency on which Earhart heard the Itasca's transmissions; if the Itasca could have transmitted to her in voice on this frequency, the problems with the [[direction finding]] might have been sorted out.

	The [[Itasca]] was only prepared to transmit voice on 3105 kcs:		The [[Itasca]] was only prepared to transmit voice on 3105 kcs:

Moleski at 22:50, 12 October 2009

2009-10-12T22:50:45Z

← Older revision		Revision as of 22:50, 12 October 2009
Line 25:		Line 25:
	:The single audio amplifier stage in this transmitter was driven by audio from a carbon-type microphone, transformer-coupled to the audio tube control grid.<ref>[http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#6 Mike Everette, "A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020."]</ref>		:The single audio amplifier stage in this transmitter was driven by audio from a carbon-type microphone, transformer-coupled to the audio tube control grid.<ref>[http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#6 Mike Everette, "A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020."]</ref>

	One of the [[what went wrong\|breakdowns in communication]] between the [[Itasca]] and [[NR16020]] was due to the fact that Itasca's [[frequency\|high-frequency transmitter]] (the one used to transmit on 7500 kcs) was not equipped with a microphone and voice modulation. The Itasca could only transmit using [[CW]] ~~and~~ [[~~Morse Code~~]] on that frequency. Tragically, this was the only frequency on which Earhart heard the Itasca's transmissions; if the Itasca could have transmitted to her in voice on this frequency, the problems with the [[direction finding]] might have been sorted out.		One of the [[what went wrong\|breakdowns in communication]] between the [[Itasca]] and [[NR16020]] was due to the fact that Itasca's [[frequency\|high-frequency transmitter]] (the one used to transmit on 7500 kcs) was not equipped with a microphone and voice modulation.<ref>[http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/traffic.html#628 6/28/37 from Itasca:] "ITASCA TRANSMITTERS CALIBRATED 7500 6210 3105 500 AND 425 KCS CW AND LAST THREE EITHER CW OR MCW."</ref> The Itasca could only transmit using [[Morse Code]] transmitted via [[CW]] on that frequency.<ref>[http://www.tighar.org/TTracks/12_2/logjam.html "Log Jam."]</ref> Tragically, this was the only frequency on which Earhart heard the Itasca's transmissions; if the Itasca could have transmitted to her in voice on this frequency, the problems with the [[direction finding]] might have been sorted out.

			The [[Itasca]] was only prepared to transmit voice on 3105 kcs:

			:ALL COMMUNICATION FROM PLANE WILL BE ON 500, 3105 OR 6210 KILOCYCLES BY VOICE, POSITIONS BEING GIVEN AT FIFTEEN AND FORTY FIVE MINUTES PAST THE HOUR. ITASCA ADJUST TRANSMITTER FOR POSSIBLE USE 3105 KILOCYCLES FOR VOICE.<ref>[http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/traffic.html#625 "Radio Traffic," 6/25/37.]</ref>

	== Related articles ==		== Related articles ==

Moleski: /* Related articles */

2009-10-06T20:22:54Z

← Older revision		Revision as of 20:22, 6 October 2009
Line 29:		Line 29:
	== Related articles ==		== Related articles ==
	* [[Radio equipment on NR16020]]		* [[Radio equipment on NR16020]]
	* [[~~Continuous wave]]~~		* [[Frequency, wavelength, and antenna tuning]]
	* [[ ]]
	* [[ ]]

	== References ==		== References ==

Moleski: New page: ;Correlative terms that may appear in TIGHAR resources : phone : radiotelephone, radiotelephony : voice transmission {| border=1 cellpadding=5 |+'''Classification of transmission modes'''...

2009-10-06T20:22:10Z

New page: ;Correlative terms that may appear in TIGHAR resources : phone : radiotelephone, radiotelephony : voice transmission {| border=1 cellpadding=5 |+'''Classification of transmission modes'''...

New page

;Correlative terms that may appear in TIGHAR resources
: phone
: radiotelephone, radiotelephony
: voice transmission

{| border=1 cellpadding=5
|+'''Classification of transmission modes'''
|-
|A1
|[[Continuous wave]] (CW)
|-
|A2
|[[Modulated continuous wave]] (MCW)
|-
|A3
|'''Voice modulation, radiotelephone'''
|}

To transmit voice over the radio, the audio wave pattern picked up by a microphone is superimposed on the transmitter's carrier wave; the audio wave ''modulates'' (controls the shape of) the radio wave.

To equip a transmitter to send voice, one needs at least a microphone and a modulator circuit. In the [[Radio equipment on NR16020]], the audio waveform picked up by the microphone was amplified in the modulator:

:The Model 13C transmitter employed screen-grid modulation of the power amplifier stage. This is a form of low-level modulation in which audio voltage is coupled to the amplifier tube screen grids through a transformer, after being amplified in an audio power stage.

:The single audio amplifier stage in this transmitter was driven by audio from a carbon-type microphone, transformer-coupled to the audio tube control grid.<ref>[http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#6 Mike Everette, "A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020."]</ref>

One of the [[what went wrong|breakdowns in communication]] between the [[Itasca]] and [[NR16020]] was due to the fact that Itasca's [[frequency|high-frequency transmitter]] (the one used to transmit on 7500 kcs) was not equipped with a microphone and voice modulation. The Itasca could only transmit using [[CW]] and [[Morse Code]] on that frequency. Tragically, this was the only frequency on which Earhart heard the Itasca's transmissions; if the Itasca could have transmitted to her in voice on this frequency, the problems with the [[direction finding]] might have been sorted out.

== Related articles ==
* [[Radio equipment on NR16020]]
* [[Continuous wave]]
* [[ ]]
* [[ ]]

== References ==
<references />


[[Category:Radio considerations]]