August 1999 560-0401-00
Apollo SL70
The Apollo SL70 Mode C Transponder complements the Apollo SL series of
slimline avionics. The SL70 provides Mode A/C functionality certified to
TSO-C74c Class 2A meeting VFR and IFR requirements, operates on 10-35
VDC, includes squawk code display and selection, standby, altitude, and ident
operation. All of these features are contained in the space-saving 1.3”H x
6.25”W form factor, with bright easy-to-read LED characters, and user-
friendly operation. A photocell on the front of the SL70 adjusts the LED
intensity for ambient light conditions. The SL70 will automatically test its
receive function if no interrogations have been received in the last 30 seconds.
Knobs
A single knob on the left side controls power on/off. Rotate the knob
clockwise to turn transponder power on. Rotate the knob counterclockwise to
turn power off.
Dual concentric knobs on the right side are used to select squawk codes and
change altitude values. Turning the large, outer knob moves the cursor to
allow editing of the selected character. Turning the small, inner knob changes
values.
Pushbuttons
Press the pushbutton once to activate the selected operation. An LED above
each pushbutton will light when that button is pressed.
IDENT
Press the IDENT button once to reply with an identifying squawk code, Ident
mode. In Ident mode, the Reply LED will be lighted for 20 seconds. The
Reply (Ident) LED will also flash when the SL70 generates transponder
replies.
SBY
Press SBY to place the transponder in “Standby” mode. The SL70 is “on,” but
no information will be transmitted.
ON
Press for Mode A operation. The SL70 is “on” and will transmit its squawk
code when interrogated.
ALT
Press for Mode C operation. The SL70 is “on” and will transmit its squawk
code and altitude when interrogated.
VFR
Press VFR once to set the VFR squawk code. Press VFR a second time to
toggle between the VFR squawk code and the previously entered code.
HLD
Press to enable/disable altitude hold. The LED above the HLD button is
lighted when altitude hold is enabled.
Selecting a Squawk Code
The selected squawk code will always be in use. As you change a squawk
code, the original code will be sent until you are finished selecting the new
code. When changing a code, the display will stop flashing and selection is
stopped if the controls are not used for three seconds or more. Pressing any
pushbutton will also end code selection. The squawk code is automatically
reset to the VFR code when the SL70 is turned back on.
1. Rotate the LARGE knob clockwise one position. The first character of the
squawk code will flash.
2. Rotate the SMALL knob to the desired number for the first digit.
3. Rotate the LARGE knob to move the cursor to the next desired digit. Turn
the SMALL knob to select the desired number.
4. Repeat step 3 for each of the desired digits.
