Portsdown 4 ISS Tracker - Revision history

G8GKQ: /* Portsdown Implementation */

2026-04-24T14:24:30Z

Portsdown Implementation

G8GKQ: /* Offsets */

2026-04-21T19:55:06Z

Offsets

G8GKQ: /* Supported HamLib Rotator Controllers */

2026-04-21T15:37:56Z

Supported HamLib Rotator Controllers

G8GKQ: /* Offsets */

2026-04-21T15:36:57Z

Offsets

G8GKQ: /* Offsets */

2026-04-21T15:35:29Z

Offsets

G8GKQ: /* Offsets */

2026-04-21T15:19:39Z

Offsets

G8GKQ: /* Details */

2026-04-21T15:18:45Z

Details

G8GKQ: /* Flip Mode */

2026-04-21T15:18:37Z

Flip Mode

G8GKQ: /* Flip Mode */

2026-04-21T15:18:09Z

Flip Mode

G8GKQ: /* Portsdown Implementation */

2026-04-21T14:22:10Z

Portsdown Implementation

← Older revision		Revision as of 14:24, 24 April 2026
Line 18:		Line 18:

	Now select "Track ISS". You should see the demanded position for the ISS displayed above the buttons, and the dish will move to track the position if it is more than 5 degrees above the horizon. Selecting "Track Moon", or "Track Sun" will also display the demanded position, and the dish will track if above 5 degrees.		Now select "Track ISS". You should see the demanded position for the ISS displayed above the buttons, and the dish will move to track the position if it is more than 5 degrees above the horizon. Selecting "Track Moon", or "Track Sun" will also display the demanded position, and the dish will track if above 5 degrees.
		+
		+	'''IMPORTANT''' The ISS tracker calculates the azimuth and elevation based on the locator that you have entered for your station in the Portsdown. Check that this is set correctly!

	===Details===		===Details===

@@ Line 44: / Line 44: @@
 * Then press "Cancel Offset" and you should hopefully see the noise rise on the Noise Meter as Sun Noise is received.
 * Apply an offset of 3 or 4 degrees in each direction in turn and observe whether there is any increase in noise with the offset (indicatiing that the dish alignment needs to be adjusted) or whether is decreases in all directions (indicating correct alignment).  Note that an offset of 3 or 4 degrees will need to be applied in each case to make the dish move - many rotator controllers will not move for only 1 or 2 degrees of demanded movement.
-* If you need to make a physical adjustment to the dish repeat 3 steps above to confirm alignment.
+* If you need to make a physical adjustment to the dish repeat the 3 steps above to confirm alignment.
 Any offset is applied to ISS Moon or Sun tracking in "Flip Disabled" mode.  It may be applied incorrectly in Flip modes - the maths has not been tested!

← Older revision		Revision as of 15:37, 21 April 2026
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	1701 Prosistel Prosistel D 0.3 Beta		1701 Prosistel Prosistel D 0.3 Beta
	1801 Meade LX200 0.1 Alpha		1801 Meade LX200 0.1 Alpha
		+
		+	===Acknowledgements===
		+
		+	Thanks to Paul M0EYT for the original Python tracking program.

← Older revision		Revision as of 15:36, 21 April 2026
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	Good ISS reception on a 90cm dish only needs 1 - 2 dB of sun noise.		Good ISS reception on a 90cm dish only needs 1 - 2 dB of sun noise.
		+
		+	===Tracking while Receiving===
		+
		+	The tracker is designed to keep running whilst the ISS is received on the same Portsdown. Clearly no indication of dish position is provided during receive.

	===Supported HamLib Rotator Controllers===		===Supported HamLib Rotator Controllers===

@@ Line 39: / Line 39: @@
 ===Offsets===
-The 5 offset buttons are provided to allow exact alignment of the dish on the sun before use for ISS tracking.
+The 5 offset buttons are provided to allow exact alignment of the dish on the sun before ISS tracking.  To achieve this, set up a Noise Meter (such as the Portsdown Lime or Pluto Noise Meter) in place of your MiniTiouner (or SDR) in your HamTV receive set-up.
 ===Supported HamLib Rotator Controllers===

← Older revision		Revision as of 15:19, 21 April 2026
Line 38:		Line 38:

	===Offsets===		===Offsets===
		+
		+	The 5 offset buttons are provided to allow exact alignment of the dish on the sun before use for ISS tracking.

	===Supported HamLib Rotator Controllers===		===Supported HamLib Rotator Controllers===

← Older revision		Revision as of 15:18, 21 April 2026
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	Selecting "Track Moon", "Track ISS" or "Track Sun" will always display the current position of the object in the sky. When "Stop" or "Park" are selected, the display of Demanded Position may not be valid. If using the g5500pi controller, the actual position of the dish is also displayed when "Track Moon", "Track ISS" or "Track Sun" is selected. It is hoped to extend this capability to HamLib controllers in the future.		Selecting "Track Moon", "Track ISS" or "Track Sun" will always display the current position of the object in the sky. When "Stop" or "Park" are selected, the display of Demanded Position may not be valid. If using the g5500pi controller, the actual position of the dish is also displayed when "Track Moon", "Track ISS" or "Track Sun" is selected. It is hoped to extend this capability to HamLib controllers in the future.
−

	===Flip Mode===		===Flip Mode===

← Older revision		Revision as of 15:18, 21 April 2026
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	The desired flip mode must currently be selected before the pass. It is hoped to automate this in a future update.		The desired flip mode must currently be selected before the pass. It is hoped to automate this in a future update.
		+
		+	===Offsets===

	===Supported HamLib Rotator Controllers===		===Supported HamLib Rotator Controllers===

@@ Line 28: / Line 28: @@
 The controller always assumes that the rotator has an end-stop at North.  To cater for ISS passes that are North of the dish location, and to better cater for overhead passes, 4 Flip Modes are available.  The Flip mode button cycles between these 4 modes:
-* Flip Mode Disabled.  In this mode the maximum demanded rotator elevation will be 90 degrees.  On ISS passes North of the dish location, some tracking time will be lost just after apogee as the rotator travels nearly 360 degrees to get to the other side of the North end-stop.  Note that this mode is the only mode comaptible with rotators that cannot achieve more than 90 degrees elevation.
+* '''Flip Mode Disabled'''.  In this mode the maximum demanded rotator elevation will be 90 degrees.  On ISS passes North of the dish location, some tracking time will be lost just after apogee as the rotator travels nearly 360 degrees to get to the other side of the North end-stop.  Note that this mode is the only mode comaptible with rotators that cannot achieve more than 90 degrees elevation.
-* Flip Mode Auto.  This mode is a placeholder for a future capability to enable unnattended auto-selection of Flip Modes.  Currently it has the same function as "Flip Mode Forced" below.
+* '''Flip Mode Auto'''.  This mode is a placeholder for a future capability to enable unnattended auto-selection of Flip Modes.  Currently it has the same function as "Flip Mode Forced" below.
-* Flip Mode Forced.  In this mode, the azimuth is set to (demanded azimuth =/- 180 degrees) and the elevation is set to (180 - the demanded elevation).  The effect of this is that the dish tracks the ISS "upside down" (beware waterproofing!) and the rotator end-stop is "moved" to South enabling continuous tracking of ISS passes North of the dish location.
+* '''Flip Mode Forced'''.  In this mode, the azimuth is set to (demanded azimuth =/- 180 degrees) and the elevation is set to (180 - the demanded elevation).  The effect of this is that the dish tracks the ISS "upside down" (beware waterproofing!) and the rotator end-stop is "moved" to South enabling continuous tracking of ISS passes North of the dish location.
-* Flip Mode Half-flip.
+* '''Flip Mode Half-flip'''.  This mode is designed to cope with overhead, or near-overhead, passes where the ISS is within the dish beamwidth at apogee.  Normally, such passes would need the azimuth rotator to transit 180 degrees after the ISS passed apogee, resulting in the loss of several seconds of tracking after the apogee as the demanded elevation decreased but the rotator was transiting through South while the ISS was in the East.  In this mode, the tracking is normal until the ISS reaches an elevation of 80 degrees.  Then the azimuth is frozen while the elevation still tracks to apogee; at apogee, the elevation enters flip mode, meaning that it continues to track the ISS through the overhead.  Once the ISS descends through 80 degrees again, the azimuth control is unfrozen, but in flip mode, allowing continued tracking to the horizon.
 ===Supported HamLib Rotator Controllers===

← Older revision		Revision as of 14:22, 21 April 2026
Line 18:		Line 18:

	Now select "Track ISS". You should see the demanded position for the ISS displayed above the buttons, and the dish will move to track the position if it is more than 5 degrees above the horizon. Selecting "Track Moon", or "Track Sun" will also display the demanded position, and the dish will track if above 5 degrees.		Now select "Track ISS". You should see the demanded position for the ISS displayed above the buttons, and the dish will move to track the position if it is more than 5 degrees above the horizon. Selecting "Track Moon", or "Track Sun" will also display the demanded position, and the dish will track if above 5 degrees.
		+
		+	===Details===
		+
		+	Selecting "Track Moon", "Track ISS" or "Track Sun" will always display the current position of the object in the sky. When "Stop" or "Park" are selected, the display of Demanded Position may not be valid. If using the g5500pi controller, the actual position of the dish is also displayed when "Track Moon", "Track ISS" or "Track Sun" is selected. It is hoped to extend this capability to HamLib controllers in the future.
		+
		+
		+	===Flip Mode===
		+
		+	The controller always assumes that the rotator has an end-stop at North. To cater for ISS passes that are North of the dish location, and to better cater for overhead passes, 4 Flip Modes are available. The Flip mode button cycles between these 4 modes:
		+
		+	* Flip Mode Disabled. In this mode the maximum demanded rotator elevation will be 90 degrees. On ISS passes North of the dish location, some tracking time will be lost just after apogee as the rotator travels nearly 360 degrees to get to the other side of the North end-stop. Note that this mode is the only mode comaptible with rotators that cannot achieve more than 90 degrees elevation.
		+
		+	* Flip Mode Auto. This mode is a placeholder for a future capability to enable unnattended auto-selection of Flip Modes. Currently it has the same function as "Flip Mode Forced" below.
		+
		+	* Flip Mode Forced. In this mode, the azimuth is set to (demanded azimuth =/- 180 degrees) and the elevation is set to (180 - the demanded elevation). The effect of this is that the dish tracks the ISS "upside down" (beware waterproofing!) and the rotator end-stop is "moved" to South enabling continuous tracking of ISS passes North of the dish location.
		+
		+	* Flip Mode Half-flip.

	===Supported HamLib Rotator Controllers===		===Supported HamLib Rotator Controllers===