OZ1HFT: /* Helios Small Transmitting Loop Antenna and Controller */ wiki

2011-04-21T16:37:24Z

‎Helios Small Transmitting Loop Antenna and Controller: wiki

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2010-01-25T18:37:15Z

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WR5H at 00:04, 21 January 2008

2008-01-21T00:04:15Z

WR5H at 18:05, 14 October 2007

2007-10-14T18:05:38Z

WR5H at 13:34, 9 October 2007

2007-10-09T13:34:33Z

WR5H at 02:30, 9 October 2007

2007-10-09T02:30:26Z

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WikiSysop: New page

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== Helios Small Transmitting Loop Antenna and Controller ==

← Older revision		Revision as of 18:37, 25 January 2010
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	--[[User:WR5H\|Ken]] 18:46, 8 October 2007 (PDT)		--[[User:WR5H\|Ken]] 18:46, 8 October 2007 (PDT)
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		+	[[Category:Future hardware]]

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 [[Image:LoopAntenna6.JPG]]
 Tommy's beautiful antenna on the right.
 '''The Controller'''

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 [[Image:LoopAntenna_1.jpg]]
 [[Image:LoopAntenna_020.jpg]]
 '''The Controller'''

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 '''The Controller'''
-The controller is designed on a 2.5 by 3.75-inch PWB and can either be plugged directly into the Atlas backplane, or alternately mounted away from the backplane and connected to the Atlas by three signal wires and a ground.  The controller can be powered from the Atlas backplane or alternatively, powered from an on-board 5-volt regulator.  The power can then be supplied by a wall wart delivering anywhere between 8 and 20 volts ac or dc.  There are five switches and six indicator lights that operate the controller.  These switches can be mounted on the PWB or can be located off-board.  Dual footprints are provided for either miniature screw terminals or headers.  Motor voltage, being significantly higher than used by the board electronics, is connected separately.  The board has two RJ-45 type jacks; one for an eight-wire CAT5 or CAT6 cable that is used to power the stepper motor; the second is for a four-wire telephone cord that brings the position pot signals to the board.  A six-pin header connects to an in-circuit programmer to initially program the PIC.  There are a number of spare inputs for experimentation and expansion.  The controller takes digital signals corresponding to the SDR DDS frequency and positions the antenna tuning capacitor so that it resonates the antenna at, or very near, to this frequency.  As the frequency of the SDR is changed over the range of the antenna, the antenna tuning motor/controller will keep the antenna at resonance.  Since the antenna exhibits the same high Q performance while receiving as during transmitting, the antenna needs to be tuned for reception as well.  Note that this controller will also be able to be adapted to many types of motor-driven local or remote antenna tuners to offer the same “always tuned” performance.
+The controller is designed on a 2.5 by 3.75-inch PWB and can either be plugged directly into the Atlas backplane, or alternately mounted away from the backplane and connected to the Atlas by three signal wires and a ground.  The controller can be powered from the Atlas backplane or alternatively, powered from an on-board 5-volt regulator.  The power can then be supplied by a wall wart delivering anywhere between 8 and 20 volts dc.  There are five switches and six indicator lights that operate the controller.  These switches can be mounted on the PWB or can be located off-board.  Dual footprints are provided for either miniature screw terminals or headers.  Motor voltage, being significantly higher than used by the board electronics, is connected separately.  The board has two RJ-45 type jacks; one for an eight-wire CAT5 or CAT6 cable that is used to power the stepper motor; the second is for a four-wire telephone cord that brings the position pot signals to the board.  A six-pin header connects to an in-circuit programmer to initially program the PIC.  There are a number of spare inputs for experimentation and expansion.  The controller takes digital signals corresponding to the SDR DDS frequency and positions the antenna tuning capacitor so that it resonates the antenna at, or very near, to this frequency.  As the frequency of the SDR is changed over the range of the antenna, the antenna tuning motor/controller will keep the antenna at resonance.  Since the antenna exhibits the same high Q performance while receiving as during transmitting, the antenna needs to be tuned for reception as well.  Note that this controller will also be able to be adapted to many types of motor-driven local or remote antenna tuners to offer the same “always tuned” performance.
 The heart of the controller is a PIC 18F4321 processor, which are normally available from Mouser and other suppliers for about $5.00 ea.  Microchip has an extensive website and tons of free software as well as a free IDE.  The 18F4321 is used since it has internal communication ports, A/D converters, and PWM motor controllers.  If using the PWB developed for this project, you will need a programmer capable of programming the 18F4321 through the in-circuit port, and use the free IDE from Microchip.  These programmers are available on Ebay starting at around $30.