AT-11 Datasheet, PDF (5/15 Pages) List of Unclassifed Manufacturers – AT-11 Automatic Antenna Tuner

Use the stand offs to mount the PC board in the box. Use the four mounting holes provided on the PC board, do
not drill the mounting holes on the PC board holes to make them larger.
Switch 1-7 and LED 1-4 mount on the front panel and J1 and 2 mount on the rear panel. The power
switch, SW6 connects to the two wire holes near the power jack.
The mode switch, SW7 mounts next to the power switch. It connects to J3. Grounding the pin is Auto
mode, letting it float is Semi. The 5 push buttons mount nearly in the center of the front panel and the LEDs
just push through holes. Note the polarity of the LEDs. The flattened side (on the plastic part of the LED) should
go to ground. You can see the flattened side by looking at the LED with the leads facing you. The flattened side
will be right next to one of the leads. You may want to use some silicon RTV, hot melt glue or adhesive to help
hold in the LEDs in place.
J3 is laid out on the board as a 14 pin header with 0.1 inch spacing (figure 8). A header and connector
with ribbon wire is provided for wiring the front panel components. See figure 9 for the wire designations.
The wires from the SO-239 can be left over #18 gauge wire from L1-8. You should only need about 2
or 3 inches to make the connection (figure 10). Be sure to note that the #18 gauge wire on the radio side goes
through the center of T1. Also, bring a ground wire from each SO-239 to the PC board. Be sure to scrape the
insulation off the ends of the wire before soldering.
Once everything is mounted and wired, U1(the 68HC11) can be placed into the socket and power
applied. Notice that U1 has a flattened corner that should match the socket. On power up, the AT-11 will flash
all LEDs once to indicate that everything has initialized successfully. Current draw should be around 10 mA.
Each relay draws about 30 mA when energized. If a relay energizes on power up (a sign there is a
problem), you will not be able to tell (by current draw) if the processor is working properly. No relays
should energize when the unit is first powered on. The maximum current draw is about 500 mA with all the
relays energized. Since it is rare that all relays are energized, the average current draw is about 200 mA.
Alignment: The AT-11 can be powered on or off during alignment. We recommend to leave it off so that other
components that may have problems will not interfere. If you leave it on during alignment, be sure to place the
semi/auto switch in the semi position. Otherwise, it will start tuning while you are making adjustments. Set
VR39 and 40 to the center position. With a voltmeter on test point REV (to the left of VR39) and about 10
watts applied and a dummy load or resonant antenna on the output, tune C35 for minimum DC voltage. It should
dip to just about 0.0 volts (0.1 is Ok). You MUST use a 50 ohm load (either dummy or antenna) to properly do
the alignment.
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