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how one lead is longer than the other. The longer of the two leads is the
anode, or (+) connection. Most diodes also have a flat molded in the
component body. This corresponds to the cathode or (-) side of the part.
Note also that while both of the holes is rectangular, only one of the
holes has the corners "rounded off". The longer (anode) lead belongs in
the "rounded off" hole, and the shorter (cathode) lead belongs in the rec-
tangular (non-rounded) hole. Now for the fun part! When mounting the
direction heading LED's we would like the height of the diodes from the
circuit board to be at just the correct height to protrude through the top
panel of the unit. The easiest way to accomplish this task is to slide the
LED's into place making absolutely sure that the "flat" side of the diodes
are correctly oriented as seen on the silkscreen. D3, 4, 17, 18, 19, 20,
21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32 are RED LED's , while D16
is the GREEN LED. Once the LED's are loosely into place, temporarily
fit the circuit board into the case top, and when tipped over the LED's
should fall into their respective holes.
88. With the 19 LED's correctly oriented and set to the correct height,
solder into place.
The main board assembly is complete! You are that much closer to a func-
tioning Doppler DF system. Take a break...you have accomplished the big-
gest "chunk" of the kit. When we start up again, we'll be creating an antenna
switching system for the direction finder
ASSEMBLY INSTRUCTIONS FOR THE ANTENNA SYSTEM
Roll those sleeves back up; we'll get to the antenna switcher and individual
antenna assemblies to complete the Doppler DF kit.
Have a look at the ANTINT-1 antenna interface board. This is where we will
accomplish the solid state switching between each antenna, Please note that
this circuit board will be operating at RF frequencies; proper assembly tech-
niques (i.e. short component lead lengths, coaxial cable connections ) will be
critical on this board and the antenna assemblies. To minimize these imped-
ance destroying lead lengths, we have opted for a "surface mount" proce-
dure of the remaining components. Therefore instead of the typical "thru hole
assembly" you have completed on the main board, the components on this
assembly will be soldered on the same side of the circuit board. It is neces-
sary to preform the components and trim excess leads prior to the compo-
nent being installed.
1. Form and install diodes D1,
2, 3, 4 into their respective po-
sitions on the circuit board.
Diode Mounting Diagram
DDF1 • 24
Solder Connection
Circuit Trace
PC Board
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