RTL-SDR AIS Ship Tracking - Revision history

Mol: /* Antenna */

2026-05-08T12:53:26Z

Antenna

← Older revision		Revision as of 15:53, 8 May 2026
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	* https://www.rtl-sdr.com/rtl-sdr-tutorial-cheap-ais-ship-tracking/		* https://www.rtl-sdr.com/rtl-sdr-tutorial-cheap-ais-ship-tracking/
	* https://www.waves.utoronto.ca/prof/svhum/ece422/notes/13-folded.pdf		* https://www.waves.utoronto.ca/prof/svhum/ece422/notes/13-folded.pdf

			<youtube>
			TmR0kJ_xhp4
			</youtube>

	=== Programming ===		=== Programming ===

Mol: /* Antenna */

2026-05-08T12:51:22Z

Antenna

← Older revision		Revision as of 15:51, 8 May 2026
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	\|}		\|}

	~~<code>~~		Driven element (dipole) form: Straight. Element shape: Flat. Elements are isolated from the metal boom. The calculation is taking into account the boom-correction.
	Driven element (dipole) form: Straight		*Frequency f: 162 MHz
	Element shape: Flat		*Wavelength λ: 1 m 851 mm
			*Element width w: 23 mm
			*Element thickness t: 1 mm
			*Boom diameter D: 13 mm

	~~Frequency f: 162 MHz~~
	~~Wavelength λ: 1 m 851 mm~~
	~~Element width w: 23 mm~~
	~~Element thickness t: 1 mm~~
	~~Boom diameter D: 13 mm~~

	~~Total number of elements: 5~~		{\| class="wikitable"
	~~Boom length: 1 m 263~~ mm		\|-
	~~Gain: 10 dBi (approx.)~~		!
			! Distance
	Reflector ~~length R: 902 mm~~		! Spacing [mm]
	~~Reflector position R =~~ 0		! Length [mm]
			\|-
	~~Dipole length F: 869 mm~~		\| Reflector
	~~Dipole position F (R~~-~~F): 370 mm~~		\| 0
	~~Gap at connection point~~ g <~~= 24~~.~~7 mm~~		\| 0
			\| 902
	~~Length D1: 804 mm~~		\|-
	~~Director position D1 (R~~-D1): 509 mm		\| DE gap g<23.7mm
	~~Distance F-D1:~~ 139 mm		\| 370
			\| 370
	~~Length~~ D2~~: 793 mm~~		\| 869
	~~Director position D2 (R-D2): 842 mm~~		\|-
	~~Distance D1-D2:~~ 333 mm		\| D1
			\| 509
	~~Length D3: 783 mm~~		\| 139
	~~Director position D3 (R~~-~~D3): 1 m 240 mm~~		\| 804
	~~Distance D2-~~D3~~: 398 mm~~		\|-
			\| D2
	~~Elements are isolated from the metal boom.~~		\| 942
	~~The calculation is taking into account the boom-correction.~~		\| 333
	~~</code>~~		\| 793
			\|-
			\| D3
			\| 1240
			\| 398
			\| 783
			\|}

Mol: /* Antenna */

2026-05-08T12:46:56Z

Antenna

← Older revision		Revision as of 15:46, 8 May 2026
Line 283:		Line 283:

	<code>		<code>
	--
	Driven element (dipole) form: Straight		Driven element (dipole) form: Straight
	Element shape: Flat		Element shape: Flat
	--
	Frequency f: 162 MHz		Frequency f: 162 MHz
	Wavelength λ: 1 m 851 mm		Wavelength λ: 1 m 851 mm
Line 296:		Line 295:
	Boom length: 1 m 263 mm		Boom length: 1 m 263 mm
	Gain: 10 dBi (approx.)		Gain: 10 dBi (approx.)
	~~-------------------------------------------------------------~~
	Reflector length R: 902 mm		Reflector length R: 902 mm
	Reflector position R = 0		Reflector position R = 0
	~~-------------------------------------------------------------~~
	Dipole length F: 869 mm		Dipole length F: 869 mm
	Dipole position F (R-F): 370 mm		Dipole position F (R-F): 370 mm
	Gap at connection point g <= 24.7 mm		Gap at connection point g <= 24.7 mm
	~~-------------------------------------------------------------~~
	Length D1: 804 mm		Length D1: 804 mm
	Director position D1 (R-D1): 509 mm		Director position D1 (R-D1): 509 mm
	Distance F-D1: 139 mm		Distance F-D1: 139 mm
	~~-------------------------------------------------------------~~
	Length D2: 793 mm		Length D2: 793 mm
	Director position D2 (R-D2): 842 mm		Director position D2 (R-D2): 842 mm
	Distance D1-D2: 333 mm		Distance D1-D2: 333 mm
	~~-------------------------------------------------------------~~
	Length D3: 783 mm		Length D3: 783 mm
	Director position D3 (R-D3): 1 m 240 mm		Director position D3 (R-D3): 1 m 240 mm
	Distance D2-D3: 398 mm		Distance D2-D3: 398 mm
	~~-------------------------------------------------------------~~
	Elements are isolated from the metal boom.		Elements are isolated from the metal boom.
	The calculation is taking into account the boom-correction.		The calculation is taking into account the boom-correction.

Mol: /* Antenna */

2026-05-08T12:46:16Z

Antenna

← Older revision		Revision as of 15:46, 8 May 2026
Line 283:		Line 283:

	<code>		<code>
	~~-----------------------------------------------------------~~--		--
	Driven element (dipole) form: Straight		Driven element (dipole) form: Straight
	Element shape: Flat		Element shape: Flat
	~~-----------------------------------------------------------~~--		--
	Frequency f: 162 MHz		Frequency f: 162 MHz
	Wavelength λ: 1 m 851 mm		Wavelength λ: 1 m 851 mm

Mol: /* Antenna */

2026-05-08T12:45:25Z

Antenna

← Older revision		Revision as of 15:45, 8 May 2026
Line 281:		Line 281:
	\| 709		\| 709
	\|}		\|}

			<code>
			-------------------------------------------------------------
			Driven element (dipole) form: Straight
			Element shape: Flat
			-------------------------------------------------------------
			Frequency f: 162 MHz
			Wavelength λ: 1 m 851 mm
			Element width w: 23 mm
			Element thickness t: 1 mm
			Boom diameter D: 13 mm

			Total number of elements: 5
			Boom length: 1 m 263 mm
			Gain: 10 dBi (approx.)
			-------------------------------------------------------------
			Reflector length R: 902 mm
			Reflector position R = 0
			-------------------------------------------------------------
			Dipole length F: 869 mm
			Dipole position F (R-F): 370 mm
			Gap at connection point g <= 24.7 mm
			-------------------------------------------------------------
			Length D1: 804 mm
			Director position D1 (R-D1): 509 mm
			Distance F-D1: 139 mm
			-------------------------------------------------------------
			Length D2: 793 mm
			Director position D2 (R-D2): 842 mm
			Distance D1-D2: 333 mm
			-------------------------------------------------------------
			Length D3: 783 mm
			Director position D3 (R-D3): 1 m 240 mm
			Distance D2-D3: 398 mm
			-------------------------------------------------------------
			Elements are isolated from the metal boom.
			The calculation is taking into account the boom-correction.
			</code>

Mol: /* Antenna */

2026-05-08T12:44:22Z

Antenna

← Older revision		Revision as of 15:44, 8 May 2026
Line 139:		Line 139:

	Some online antenna design softwares		Some online antenna design softwares
			* https://3g-aerial.biz/en/online-calculations/antenna-calculations/dl6wu-yagi-uda-antenna-online-calculator
	* https://www.k7mem.com/Ant_Yagi_VHF_Quick.html		* https://www.k7mem.com/Ant_Yagi_VHF_Quick.html
	* https://jeroen.steeman.org/Antenna/Yagi-Antenna-Calculator		* https://jeroen.steeman.org/Antenna/Yagi-Antenna-Calculator

Mol: /* Antenna */

2026-05-08T09:49:57Z

Antenna

← Older revision		Revision as of 12:49, 8 May 2026
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	=== Antenna ===		=== Antenna ===

			The STL files for my antenna design: [[https://wiki.luntti.net/index.php?title=File:Antenna.zip\|Antenna.zip]].

	Measuring tape antenna: https://hamradioprep.com/how-to-build-a-tape-measure-yagi-antenna/		Measuring tape antenna: https://hamradioprep.com/how-to-build-a-tape-measure-yagi-antenna/

Mol: /* Antenna */

2026-05-07T15:45:28Z

Antenna

← Older revision		Revision as of 18:45, 7 May 2026
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	Other antenna types I considered:		Other antenna types I considered:
	* ''Quarter wave / dipole''. One vertical 1/4 wave element connected to the center of the coax cable and 4 (or more) more grounding elements pointing towards the the ground at 45 deg. A quarter wave antenna calculator: https://jeroen.steeman.org/Antenna/Quarter-Wave-Antenna-Calculator		* ''Quarter wave / dipole''. One vertical 1/4 wave element connected to the center of the coax cable and 4 (or more) more grounding elements pointing towards the the ground at 45 deg. All elements share the same length; 1/4 λ. This gives it about 463 mm. It requires a ground plane or reflection to operate. A quarter wave antenna calculator: https://jeroen.steeman.org/Antenna/Quarter-Wave-Antenna-Calculator
	* ''Coax collinear antenna''. Very high omnidirectional gain. Multiple short coax cables where the outer conductor is connected to the inner conductor in an alternating fashion.		* ''Coax collinear antenna''. Very high omnidirectional gain. Multiple short coax cables where the outer conductor is connected to the inner conductor in an alternating fashion.
	* ''Slim Jim''.		* ''Slim Jim''.

Mol: /* Antenna */

2026-05-07T12:12:00Z

Antenna

← Older revision		Revision as of 15:12, 7 May 2026
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	The other antenna with Metal boom (insulated), boom diameter 13 mm, Driven element diameter 25 mm and parasitic element diameter 25 mm		The other antenna with Metal boom (insulated), boom diameter 13 mm, Driven element diameter 25 mm and parasitic element diameter 25 mm

			{\| class="wikitable"
			\|-
			!
			! Spacing
			! Length
			\|-
			\| Reflector
			\| 0
			\| 896.2
			\|-
			\| DE
			\| 370.1
			\| 873.8
			\|-
			\|
			\| 508.9
			\| 779.0
			\|-
			\|
			\| 842.0
			\| 767.9
			\|-
			\|
			\| 1239.9
			\| 756.23
			\|-
			\|
			\| 1702.5
			\| 745.3
			\|-
			\|
			\| 2220.7
			\| 735.8
			\|-
			\|
			\| 2775.9
			\| 727.6
			\|-
			\|
			\| 3358.79
			\| 720.0
			\|-
			\|
			\| 3969.5
			\| 714.4
			\|-
			\|
			\| 4607.9
			\| 709
			\|}

Mol: /* Antenna */

2026-05-07T12:05:40Z

Antenna

← Older revision		Revision as of 15:05, 7 May 2026
Line 226:		Line 226:


			The other antenna with Metal boom (insulated), boom diameter 13 mm, Driven element diameter 25 mm and parasitic element diameter 25 mm


	Driven element is a dipole element [or actually a half-dipole], thus the length should be <math>\ell = \tfrac12 \lambda = \tfrac12 \frac{c}{f}= \frac12 \frac{299792458}{160 \times 10^6} = \tfrac12 \times 1.85 = 0.925 </math> (m). A slightly different number for speed of light (speed of radio waves in the antenna; <math>v \approx 0.97 c</math>) makes the <math>\ell</math> to be <math>\ell = 0.8975</math> m. The driven element has an additional parallel wire connecting its two ends, and is called a ''folded dipole''. Thus two nearly identical radiating currents are generated. See [https://en.wikipedia.org/wiki/Loop_antenna loop antenna]. Folded dipole consists of a ''split dipole'' and an unbroken ''impedance transformer'', and those two elements are connected together at both ends. The gap should be fixed to keep the wires at a constant separation distance. Spacing is the distance between the two parts of the driven element.		Driven element is a dipole element [or actually a half-dipole], thus the length should be <math>\ell = \tfrac12 \lambda = \tfrac12 \frac{c}{f}= \frac12 \frac{299792458}{160 \times 10^6} = \tfrac12 \times 1.85 = 0.925 </math> (m). A slightly different number for speed of light (speed of radio waves in the antenna; <math>v \approx 0.97 c</math>) makes the <math>\ell</math> to be <math>\ell = 0.8975</math> m. The driven element has an additional parallel wire connecting its two ends, and is called a ''folded dipole''. Thus two nearly identical radiating currents are generated. See [https://en.wikipedia.org/wiki/Loop_antenna loop antenna]. Folded dipole consists of a ''split dipole'' and an unbroken ''impedance transformer'', and those two elements are connected together at both ends. The gap should be fixed to keep the wires at a constant separation distance. Spacing is the distance between the two parts of the driven element.