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LDG AT-1000 Manual
Summary of AT-1000
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Ldg at-1000 1kw automatic memory antenna tuner ldg electronics 1445 parran road, po box 48 st. Leonard md 20685-2903 usa phone: 410-586-2177 fax: 410-586-8475 ldg@ldgelectronics.Com www.Ldgelectronics.Com 1.
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Ldg at-1000 1kw automatic antenna tuner table of contents introduction 2 important safety warnings 2 jumpstart, or “real hams don’t read manuals!” 3 specifications 3 operating instructions 4 getting to know your at-1000 4 installation 5 operation 6 theory of operation 9 some basic ideas about impeda...
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Jumpstart, or “real hams don’t read manuals!” ok, but at least read this one section before you transmit: safety warning: never operate your at-1000 with the cover removed; lethal rf voltages may be present during operation. Never exceed specifications. 1. Connect your at-1000 to a source of 11 – 15...
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Operating instructions getting to know your at-1000 your at-1000 is a quality, precision instrument that will give you many years of outstanding service; take a few minutes to get to know it. On the front panel, there are six pushbutton switches: • power: turns your at-1000 on and off • manual capac...
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On the back panel, there are four connectors: • dc power input (2.5 x 5.5 mm coaxial power connector, center pin positive) • rf in (marked “transmitter”, standard so-239 socket) • rf out (marked “antenna”, standard so-239 socket) • ground (wingnut) “what’s the deal with the hole?” sharp-eyed users w...
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Lead are positive. When you connect to dc power, the power led will flash once, and the tuner will remain in the off state. Operation meter bounce codes in addition to displaying power and swr, the power meters also indicate several important tuner states. The meters are used as a kind of digital ou...
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Cap dn: the cap dn button subtracts capacitance; holding the button down auto-repeats the subtract. Both meters bounce fast at the low mark when you reach the lower capacitance limit. Ind up: the ind up button adds inductance; holding the button down auto-repeats the add. Both meters bounce fast at ...
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Power too high: if the power exceeds 125 watts, a tuning cycle will not begin, both meters bounce fast at the high mark. They will continue to bounce until the rf is removed. In this case, reduce power and begin a new tuning cycle. Swr too high for the power level: if power exceeds 100 watts while t...
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Fine-tuning the tuner in rare circumstances, the automatic tuning cycle will end with a relative high swr, perhaps 1.8 or 2. This is usually due to operation far from the antenna’s natural resonant frequency. You can manually adjust the match using the ind and cap up and dn buttons on the front pane...
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Theory of operation some basic ideas about impedance the theory underlying antennas and transmission lines is fairly complex, and in fact employs a mathematical notation called “complex numbers” that have “real” and “imaginary” parts 2 . It is beyond the scope of this manual to present a tutorial on...
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F r f r swr / 1 / 1 − + = swr is measured using a device called an “swr bridge”, inserted in the transmission line between the amplifier and antenna. This circuit measures forward and reverse power from which swr may be calculated (some meters calculate swr for you). More advanced units can measure ...
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The ldg at-1000 in 1995 ldg pioneered a new type of automatic antenna tuner. The ldg design uses banks of fixed capacitors and inductors, switched in and out of the circuit by relays under microprocessor control. A built- in swr sensor provides feedback; the microprocessor searches the capacitor and...
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The relays operate from an external 12 volt dc power supply. The total current drawn by the at-1000 depends primarily on the number of energized relays, with the maximum current drain being approximately 1 amp. The microprocessor also needs a power supervisory circuit (u2, the 34064 ic) to provide a...
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Care and maintenance your at-1000 tuner is essentially maintenance-free; just be sure to observe the power limits discussed in this manual. The outer case may be cleaned as needed with a soft cloth slightly dampened in household cleaning solution. As with any modern electronic device, your at-1000 c...
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The extraction tool fits into opposite corners of the 68hc11 socket; the bent ends will lift the chip from beneath. Unplug the tuner, touch a ground point to avoid static discharge damage, and remove the cabinet cover. Insert the tool and pull gently and evenly on both sides to extract the chip. Pre...