Instruction manual

FMLP1 • 14
Now the inductor coils are prepared. Let’s see how they will mount to the PC
board. Look at the parts layout diagram. You will see that coil L1 and L3 mount
directly over the top of C3 and C8. The enamel on the wire will keep them from
shorting but leaving a bit of space never hurts. About 1/32
nd
of an inch does
nicely.
 15. Install L1, one of the four turn inductors, as shown on the parts layout
diagram. Leave the coil loops spread apart about the same as the bolt
threads. Use the tweezers again to keep from burning your fingers!
 16. Install L2, the five turn inductor. Compress the coil loops together
without misshaping the coil form.
 17. Install L3, the other four turn inductor. Leave the coil loops spread apart
about the same as the bolt threads like L1.
Verify again your parts placement with the parts layout diagram and keep the
coils lined up straight. You don’t want it to look like this:
Ground Shield Placement
The two brass ground shields are used to prevent RF signals from coupling
through the air and bypassing the filter stages. It is very important to solder
these well to the board for them to function as needed.
 18. Install one of the brass ground shields so that it stands vertically
between L1 and L2. Note that a strip of green solder mask is open where
the shield should be installed. The small notch in the bottom of the shield
should line up over the circuit trace connecting L1 and L2. Take care not to
short the trace to ground.
 19. Install the other brass ground shield so that it stands vertically between
L2 and L3. Use the same guidelines as the previous step.
We are almost finished. Now we just need to hook-up the coaxial cable and
arrange the board in the PVC housing!