Frequency, wavelength, and antenna tuning - Revision history

Moleski at 01:46, 5 February 2013

2013-02-05T01:46:07Z

← Older revision		Revision as of 01:46, 5 February 2013
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	There is an inverse relationship between frequency and wavelength: the lower the frequency, the longer the wavelength; the higher the frequency, the shorter the wavelength.		There is an inverse relationship between frequency and wavelength: the lower the frequency, the longer the wavelength; the higher the frequency, the shorter the wavelength.

	The frequency of a wave is measured in ''cycles per second''. Many of the historical records use "kcs" as an abbreviation for "kilocycles per second"--where "kilocycles" is "1000 cycle." At present, we use "~~Herz~~" to stand for "cycles per second."		The frequency of a wave is measured in ''cycles per second''. Many of the historical records use "kcs" as an abbreviation for "kilocycles per second"--where "kilocycles" is "1000 cycle." At present, we use "Hertz" to stand for "cycles per second."
	=== Abbreviations ===		=== Abbreviations ===

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	\|align="right"\|1		\|align="right"\|1
	\|1 cycle		\|1 cycle
	\|1 ~~Herz~~		\|1 Hertz
	\|1 Hz		\|1 Hz
	\|-		\|-
	\|align="right"\|1,000		\|align="right"\|1,000
	\|1 kilocycle (1 kc or kcs)		\|1 kilocycle (1 kc or kcs)
	\|1 ~~kiloHerz~~		\|1 kiloHertz
	\|1 kHz		\|1 kHz
	\|-		\|-
	\|align="right"\|1,000,000		\|align="right"\|1,000,000
	\|1 megacycle		\|1 megacycle
	\|1 ~~MegaHerz~~		\|1 MegaHertz
	\|1 MHz		\|1 MHz
	\|-		\|-
	\|align="right"\|1,000,000,000		\|align="right"\|1,000,000,000
	\|1 gigacycle		\|1 gigacycle
	\|1 ~~GigaHerz~~		\|1 GigaHertz
	\|1 GHz		\|1 GHz
	\|}		\|}
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	7500 kcs = 7500 kHz = 7.5 MHz		7500 kcs = 7500 kHz = 7.5 MHz

	2.4 GHz = 2.4 ~~GigaHerz~~ = 2.4 billion cycles per second (some cell phones and similar appliances)		2.4 GHz = 2.4 GigaHertz = 2.4 billion cycles per second (some cell phones and similar appliances)

	== Optimizing an antenna ==		== Optimizing an antenna ==

Moleski: /* 500 kc frequency */

2013-01-21T01:34:50Z

500 kc frequency

← Older revision		Revision as of 01:34, 21 January 2013
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	7500 kcs was not a transmission frequency for Earhart. The [[radio equipment on NR16020]] transmitted on 500 kcs, 3105 kcs, and 6210 kcs. The columns for optimum and actual antenna lengths are concerned with the Electra's transmission setup.		7500 kcs was not a transmission frequency for Earhart. The [[radio equipment on NR16020]] transmitted on 500 kcs, 3105 kcs, and 6210 kcs. The columns for optimum and actual antenna lengths are concerned with the Electra's transmission setup.

	=== 500 kc frequency ===		=== 500 kcs frequency ===

	500 kcs (or 500 kHz) was the universal emergency ''and'' calling frequency for ships at sea (once contact was made between two stations, they would switch to another frequency so as to clear the band for other traffic).[http://www.qsl.net/ae0q/nmo_pt3.htm] This meant that it was monitored continuously. Its traffic was all [[CW]]/[[Morse code]]. There would have probably have been no point in making a voice transmission on that frequency: "No one monitoring 500 would have been listening for/expecting a voice signal on 500."<ref>[[Mike Everette]], 7 Sep 2000 [http://www.tighar.org/Projects/Earhart/forum/Forum_Archives/200009.txt Forum.]</ref>		500 kcs (or 500 kHz) was the universal emergency ''and'' calling frequency for ships at sea (once contact was made between two stations, they would switch to another frequency so as to clear the band for other traffic).[http://www.qsl.net/ae0q/nmo_pt3.htm] This meant that it was monitored continuously. Its traffic was all [[CW]]/[[Morse code]]. There would have probably have been no point in making a voice transmission on that frequency: "No one monitoring 500 would have been listening for/expecting a voice signal on 500."<ref>[[Mike Everette]], 7 Sep 2000 [http://www.tighar.org/Projects/Earhart/forum/Forum_Archives/200009.txt Forum.]</ref>

Moleski at 15:37, 13 October 2009

2009-10-13T15:37:09Z

← Older revision		Revision as of 15:37, 13 October 2009
Line 50:		Line 50:
	Tuning coils can compensate to some extent for antennas that are not an even fraction or multiple of a wavelength.		Tuning coils can compensate to some extent for antennas that are not an even fraction or multiple of a wavelength.

	[[Mike Everette]], 23 October 2000 [http://www.tighar.org/forum/Highlights101_120/highlights111.html Forum.]		[[Mike Everette]], 23 October 2000 [http://www.tighar.org/Projects/Earhart/forum/Highlights101_120/highlights111.html Forum.]
	:If an antenna is a non-resonant length (as Earhart’s was) it must be tuned to compensate for its shortcomings if it is going to radiate power. Earhart’s radio had a limited capability to properly match, or tune, the antenna. The design of the unit was one which definitely encouraged harmonic radiation and a mistuned antenna further aggravated the potential for doing so.		:If an antenna is a non-resonant length (as Earhart’s was) it must be tuned to compensate for its shortcomings if it is going to radiate power. Earhart’s radio had a limited capability to properly match, or tune, the antenna. The design of the unit was one which definitely encouraged harmonic radiation and a mistuned antenna further aggravated the potential for doing so.

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	=== 500 kc frequency ===		=== 500 kc frequency ===

	500 kcs (or 500 kHz) was the universal emergency ''and'' calling frequency for ships at sea (once contact was made between two stations, they would switch to another frequency so as to clear the band for other traffic).[http://www.qsl.net/ae0q/nmo_pt3.htm] This meant that it was monitored continuously. Its traffic was all [[CW]]/[[Morse code]]. There would have probably have been no point in making a voice transmission on that frequency: "No one monitoring 500 would have been listening for/expecting a voice signal on 500."<ref>[[Mike Everette]], 7 Sep 2000 [http://www.tighar.org/forum/Forum_Archives/200009.txt Forum.]</ref>		500 kcs (or 500 kHz) was the universal emergency ''and'' calling frequency for ships at sea (once contact was made between two stations, they would switch to another frequency so as to clear the band for other traffic).[http://www.qsl.net/ae0q/nmo_pt3.htm] This meant that it was monitored continuously. Its traffic was all [[CW]]/[[Morse code]]. There would have probably have been no point in making a voice transmission on that frequency: "No one monitoring 500 would have been listening for/expecting a voice signal on 500."<ref>[[Mike Everette]], 7 Sep 2000 [http://www.tighar.org/Projects/Earhart/forum/Forum_Archives/200009.txt Forum.]</ref>

	"The frequency of 500 KHz was essential for the round-the-world flight. Until the middle of World War II, this was the only universally monitored (guarded) distress frequency. Ships at sea, and maritime shore stations, were required by international regulations to maintain watch on 500 KHz. During specified parts of every hour, radio silence would be observed in order to listen for stations in distress. At all other times, 500 KHz was a calling frequency. Ships, shore stations and aircraft made initial contact on 500, then moved to other working frequencies like 410 or 425 KHz."<ref>[[Mike Everette]], [http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#10 A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020.]</ref>		"The frequency of 500 KHz was essential for the round-the-world flight. Until the middle of World War II, this was the only universally monitored (guarded) distress frequency. Ships at sea, and maritime shore stations, were required by international regulations to maintain watch on 500 KHz. During specified parts of every hour, radio silence would be observed in order to listen for stations in distress. At all other times, 500 KHz was a calling frequency. Ships, shore stations and aircraft made initial contact on 500, then moved to other working frequencies like 410 or 425 KHz."<ref>[[Mike Everette]], [http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#10 A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020.]</ref>
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	"'Silent periods' were, however, required to be observed... about every 15 minutes, for at least 3 to 5 minutes. During those periods, operators were required to listen for transmissions from ships (or aircraft) in distress.		"'Silent periods' were, however, required to be observed... about every 15 minutes, for at least 3 to 5 minutes. During those periods, operators were required to listen for transmissions from ships (or aircraft) in distress.

	"Of course, a distress message could come at any time. If one was heard, everybody on the freq was required to QRT (cease transmitting) at once! Except for the station in distress, and whoever was in direct QSO (contact) with him."<ref>[[Mike Everette]], 20 October 2000 [http://www.tighar.org/forum/Forum_Archives/200010.txt Forum.]		"Of course, a distress message could come at any time. If one was heard, everybody on the freq was required to QRT (cease transmitting) at once! Except for the station in distress, and whoever was in direct QSO (contact) with him."<ref>[[Mike Everette]], 20 October 2000 [http://www.tighar.org/Projects/Earhart/forum/Forum_Archives/200010.txt Forum.]
	</ref>		</ref>

Moleski at 19:53, 12 October 2009

2009-10-12T19:53:53Z

← Older revision		Revision as of 19:53, 12 October 2009
Line 108:		Line 108:
	500 kcs (or 500 kHz) was the universal emergency ''and'' calling frequency for ships at sea (once contact was made between two stations, they would switch to another frequency so as to clear the band for other traffic).[http://www.qsl.net/ae0q/nmo_pt3.htm] This meant that it was monitored continuously. Its traffic was all [[CW]]/[[Morse code]]. There would have probably have been no point in making a voice transmission on that frequency: "No one monitoring 500 would have been listening for/expecting a voice signal on 500."<ref>[[Mike Everette]], 7 Sep 2000 [http://www.tighar.org/forum/Forum_Archives/200009.txt Forum.]</ref>		500 kcs (or 500 kHz) was the universal emergency ''and'' calling frequency for ships at sea (once contact was made between two stations, they would switch to another frequency so as to clear the band for other traffic).[http://www.qsl.net/ae0q/nmo_pt3.htm] This meant that it was monitored continuously. Its traffic was all [[CW]]/[[Morse code]]. There would have probably have been no point in making a voice transmission on that frequency: "No one monitoring 500 would have been listening for/expecting a voice signal on 500."<ref>[[Mike Everette]], 7 Sep 2000 [http://www.tighar.org/forum/Forum_Archives/200009.txt Forum.]</ref>

	"The frequency of 500 KHz was essential for the round-the-world flight. Until the middle of World War II, this was the only universally monitored (guarded) distress frequency. Ships at sea, and maritime shore stations, were required by international regulations to maintain watch on 500 KHz. During specified parts of every hour, radio silence would be observed in order to listen for stations in distress. At all other times, 500 KHz was a calling frequency. Ships, shore stations and aircraft made initial contact on 500, then moved to other working frequencies like 410 or 425 KHz."<ref>[[Mike Everette]], [http://~~www.~~tighar.org/Projects/Earhart/~~Bulletins~~/~~52_ElectraRadios~~/~~52_ElectraRadios~~.htm#10 A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020.]</ref>		"The frequency of 500 KHz was essential for the round-the-world flight. Until the middle of World War II, this was the only universally monitored (guarded) distress frequency. Ships at sea, and maritime shore stations, were required by international regulations to maintain watch on 500 KHz. During specified parts of every hour, radio silence would be observed in order to listen for stations in distress. At all other times, 500 KHz was a calling frequency. Ships, shore stations and aircraft made initial contact on 500, then moved to other working frequencies like 410 or 425 KHz."<ref>[[Mike Everette]], [http://tighar.org/Projects/Earhart/Research/ResearchPapers/ElectraRadios/ElectraRadios.htm#10 A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020.]</ref>

	"The 500 KHz frequency was not only a distress channel, but also a 'calling frequency.' Steamship companies maintained communications with certain coastal stations and these actually were conducted on 'working' frequencies like 418 or 425 KHz. However, the ships all were required to guard 500. So, to establish initial communication, a common 'calling' freq was essential ('I'll call you on 500, then we'll move off to 425' etc) and 500 was the logical choice.		"The 500 KHz frequency was not only a distress channel, but also a 'calling frequency.' Steamship companies maintained communications with certain coastal stations and these actually were conducted on 'working' frequencies like 418 or 425 KHz. However, the ships all were required to guard 500. So, to establish initial communication, a common 'calling' freq was essential ('I'll call you on 500, then we'll move off to 425' etc) and 500 was the logical choice.

Moleski: /* Related articles */

2009-03-05T18:40:45Z

← Older revision		Revision as of 18:40, 5 March 2009
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	* [http://en.wikipedia.org/wiki/Ionosphere Wikipedia: Ionosphere.]		* [http://en.wikipedia.org/wiki/Ionosphere Wikipedia: Ionosphere.]
	* [http://en.wikipedia.org/wiki/Radio_propagation Wikipedia: Radio propagation.]		* [http://en.wikipedia.org/wiki/Radio_propagation Wikipedia: Radio propagation.]
	* [http://www.~~csgnetwork~~.com/~~freqwavelengthcalc~~.~~html~~ Frequency / Wavelength Calculator.]		* [http://www.sengpielaudio.com/calculator-wavelength.htm Frequency / Wavelength Calculator.]

	<!-- Please leave this category marker at the bottom. You may add this article to other categories if you wish -->		<!-- Please leave this category marker at the bottom. You may add this article to other categories if you wish -->
	[[Category:Radio considerations]]		[[Category:Radio considerations]]

Moleski at 18:37, 5 March 2009

2009-03-05T18:37:25Z

← Older revision		Revision as of 18:37, 5 March 2009
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	\|- align="right"		\|- align="right"
	\|500 kcs		\|500 kcs
	\| m		\| ~600 m (599.5849)
	\|1968'		\|1968'
	\|492'		\|492'
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	\|- align="right"		\|- align="right"
	\|3105 kcs		\|3105 kcs
	\| m		\| 96.5 m
	\|316.9'		\|316.9'
	\|79.2'		\|79.2'
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	\|- align="right"		\|- align="right"
	\|6210 kcs		\|6210 kcs
	\| m		\| 48.28 m
	\|158.4'		\|158.4'
	\|39.6'		\|39.6'
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	\|- align="right"		\|- align="right"
	\|7500 kcs		\|7500 kcs
	\| m		\| ~40 m (39.972)
	\|131.2'		\|131.2'
	\|32.8'		\|32.8'

Moleski: /* Earhart's frequencies and antennas */

2009-03-05T18:31:44Z

Earhart's frequencies and antennas

← Older revision		Revision as of 18:31, 5 March 2009
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	\|-		\|-
	! Frequency		! Frequency
	! Full wavelength		! Full wavelength (meters)
	! 1/4 wavelength		! Full wavelength (feet)
			! 1/4 wavelength (feet)
	! Optimum antenna		! Optimum antenna
	! Actual antenna		! Actual antenna
	\|- align="right"		\|- align="right"
	\|500 kcs		\|500 kcs
			\| m
	\|1968'		\|1968'
	\|492'		\|492'
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	\|- align="right"		\|- align="right"
	\|3105 kcs		\|3105 kcs
			\| m
	\|316.9'		\|316.9'
	\|79.2'		\|79.2'
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	\|- align="right"		\|- align="right"
	\|6210 kcs		\|6210 kcs
			\| m
	\|158.4'		\|158.4'
	\|39.6'		\|39.6'
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	\|- align="right"		\|- align="right"
	\|7500 kcs		\|7500 kcs
			\| m
	\|131.2'		\|131.2'
	\|32.8'		\|32.8'

Moleski: /* 500 kc frequency */

2009-03-04T23:33:38Z

500 kc frequency

← Older revision		Revision as of 23:33, 4 March 2009
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	"The frequency of 500 KHz was essential for the round-the-world flight. Until the middle of World War II, this was the only universally monitored (guarded) distress frequency. Ships at sea, and maritime shore stations, were required by international regulations to maintain watch on 500 KHz. During specified parts of every hour, radio silence would be observed in order to listen for stations in distress. At all other times, 500 KHz was a calling frequency. Ships, shore stations and aircraft made initial contact on 500, then moved to other working frequencies like 410 or 425 KHz."<ref>[[Mike Everette]], [http://www.tighar.org/Projects/Earhart/Bulletins/52_ElectraRadios/52_ElectraRadios.htm#10 A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020.]</ref>		"The frequency of 500 KHz was essential for the round-the-world flight. Until the middle of World War II, this was the only universally monitored (guarded) distress frequency. Ships at sea, and maritime shore stations, were required by international regulations to maintain watch on 500 KHz. During specified parts of every hour, radio silence would be observed in order to listen for stations in distress. At all other times, 500 KHz was a calling frequency. Ships, shore stations and aircraft made initial contact on 500, then moved to other working frequencies like 410 or 425 KHz."<ref>[[Mike Everette]], [http://www.tighar.org/Projects/Earhart/Bulletins/52_ElectraRadios/52_ElectraRadios.htm#10 A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020.]</ref>

			"The 500 KHz frequency was not only a distress channel, but also a 'calling frequency.' Steamship companies maintained communications with certain coastal stations and these actually were conducted on 'working' frequencies like 418 or 425 KHz. However, the ships all were required to guard 500. So, to establish initial communication, a common 'calling' freq was essential ('I'll call you on 500, then we'll move off to 425' etc) and 500 was the logical choice.

			"There was LOTS of traffic on 500, at all times.

			"'Silent periods' were, however, required to be observed... about every 15 minutes, for at least 3 to 5 minutes. During those periods, operators were required to listen for transmissions from ships (or aircraft) in distress.

			"Of course, a distress message could come at any time. If one was heard, everybody on the freq was required to QRT (cease transmitting) at once! Except for the station in distress, and whoever was in direct QSO (contact) with him."<ref>[[Mike Everette]], 20 October 2000 [http://www.tighar.org/forum/Forum_Archives/200010.txt Forum.]
			</ref>

	=== Daytime/nighttime frequencies ===		=== Daytime/nighttime frequencies ===

Moleski at 15:42, 28 February 2009

2009-02-28T15:42:03Z

← Older revision		Revision as of 15:42, 28 February 2009
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	As a general rule, TIGHAR prefers to use the metric system. In this table, the units are given in feet to match the units used in the sources. The old abbreviation "kcs" is used because that is what appears most often in the sources (where it is not taken for granted).		As a general rule, TIGHAR prefers to use the metric system. In this table, the units are given in feet to match the units used in the sources. The old abbreviation "kcs" is used because that is what appears most often in the sources (where it is not taken for granted).

	=== Wavelengths and antennas ===		=== Wavelengths and antennas ===
	{\| border=1 cellpadding=5		{\| border=1 cellpadding=5
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	=== 500 kc frequency ===		=== 500 kc frequency ===

	500 kcs (or 500 kHz) was the universal emergency ''and'' calling frequency for ships at sea (once contact was made between two stations, they would switch to another frequency so as to clear the band for other traffic).[http://www.qsl.net/ae0q/nmo_pt3.htm] This meant that it was monitored continuously. Its traffic was all [[CW]]/[[Morse code]]. There would have probably have been no point in making a voice transmission on that frequency: "No one monitoring 500 would have been listening for/expecting a voice signal on 500" [[Mike Everette]], 7 Sep 2000 [http://www.tighar.org/forum/Forum_Archives/200009.txt Forum.]		500 kcs (or 500 kHz) was the universal emergency ''and'' calling frequency for ships at sea (once contact was made between two stations, they would switch to another frequency so as to clear the band for other traffic).[http://www.qsl.net/ae0q/nmo_pt3.htm] This meant that it was monitored continuously. Its traffic was all [[CW]]/[[Morse code]]. There would have probably have been no point in making a voice transmission on that frequency: "No one monitoring 500 would have been listening for/expecting a voice signal on 500."<ref>[[Mike Everette]], 7 Sep 2000 [http://www.tighar.org/forum/Forum_Archives/200009.txt Forum.]</ref>

			"The frequency of 500 KHz was essential for the round-the-world flight. Until the middle of World War II, this was the only universally monitored (guarded) distress frequency. Ships at sea, and maritime shore stations, were required by international regulations to maintain watch on 500 KHz. During specified parts of every hour, radio silence would be observed in order to listen for stations in distress. At all other times, 500 KHz was a calling frequency. Ships, shore stations and aircraft made initial contact on 500, then moved to other working frequencies like 410 or 425 KHz."<ref>[[Mike Everette]], [http://www.tighar.org/Projects/Earhart/Bulletins/52_ElectraRadios/52_ElectraRadios.htm#10 A Technical Analysis of the Western Electric Radio Communications Equipment Installed on Board Lockheed Electra NR16020.]</ref>

	=== Daytime/nighttime frequencies ===		=== Daytime/nighttime frequencies ===
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	The reason for having a daytime frequency different from the nighttime frequency is that the [http://en.wikipedia.org/wiki/Ionosphere ionosphere] affects [[radio wave propagation]]. An old rule of thumb is "The higher the sun, the higher the frequency."		The reason for having a daytime frequency different from the nighttime frequency is that the [http://en.wikipedia.org/wiki/Ionosphere ionosphere] affects [[radio wave propagation]]. An old rule of thumb is "The higher the sun, the higher the frequency."

	== ~~Links~~ ==		== References ==
			<references/>

			== Related articles ==
	* [http://en.wikipedia.org/wiki/Ionosphere Wikipedia: Ionosphere.]		* [http://en.wikipedia.org/wiki/Ionosphere Wikipedia: Ionosphere.]
	* [http://en.wikipedia.org/wiki/Radio_propagation Wikipedia: Radio propagation.]		* [http://en.wikipedia.org/wiki/Radio_propagation Wikipedia: Radio propagation.]

Moleski: /* Wavelengths and antennas */

2009-02-28T15:06:17Z

Wavelengths and antennas

← Older revision		Revision as of 15:06, 28 February 2009
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	\| "		\| "
	\|61.5		\|61.5
	\|46'/69' [[dorsal antenna]]		\|46'/54' [[dorsal antenna]]
	\|- align="right"		\|- align="right"
	\|3105 kcs		\|3105 kcs
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	\|79.2'		\|79.2'
	\|39.6'		\|39.6'
	\|46'/69'		\|46'/54'
	\|- align="right"		\|- align="right"
	\|6210 kcs		\|6210 kcs
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	\|39.6'		\|39.6'
	\|39.6'		\|39.6'
	\|46'/69'		\|46'/54'
	\|- align="right"		\|- align="right"
	\|7500 kcs		\|7500 kcs
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	\| n/a		\| n/a
	\|}		\|}
			7500 kcs was not a transmission frequency for Earhart. The [[radio equipment on NR16020]] transmitted on 500 kcs, 3105 kcs, and 6210 kcs. The columns for optimum and actual antenna lengths are concerned with the Electra's transmission setup.

	=== 500 kc frequency ===		=== 500 kc frequency ===