Group 42 Sells Out!

Cable Notch Filter Plans

This is just put on here because every magazine has an advertizment on how to build your own cable TV descrambler for $15, this is all you get. They are plans for a notch filter for the interfearnce scrambling method. I doubt if any cable system still uses this method. So we just saved you $15. - 4X


     ///PAY TV DECODER PLANS///

         MATERIALS REQUIRED
1   - Radio Shack mini-box ( #270-235)
1   - 1/4 watt resistor, 2.2k-2.4k ohm
      (RS #271-1325)
1   - 75pf-100pf variable capacitor
      (Hard to find)
2   - F61a chassis-type coaxia
      connectors (RS #278-212)
12" - No. 12 solid copper wir
12" - RG59 coaxial cable


         ///INSTRUCTIONS//
1.  Bare a length of No. 12 gauge solid
copper wire and twist around a 3/8
nail or rod to form a coil of 9 turns.
Elongate coil to a length of 1 1/2
inches and form right angle bends on
each end
2.  Solder the varible capacitor to
the coil. It doesn't matter where you
solder it, it still does the same job
The best place for it is in the cente
with the adjustment screw facing upward

Note: When it comes time to place coi
in box, the coil must be insulated fro
grounding.  This can be done by crazy-
glueing a piece of rubber to the bottom
of the box, and securing the coil to it.
3.  Tap coil at points 2 1/2 turns from
ends of coil and solder to coaxial
chassis connectors, bringing tap leads
through holes in chassis box.  Use as
little wire as possible.
4.  Solder resistor to center of coil
and ground other end of resistor t
chassis box, using solder lug and smal
screw
5.  Drill a 1/2" diameter hold in mini-
box cover to permit adjustment of the
variable capacitor from the outside.
Inspect the device for defects in
workmanship and place cover on mini-
box.  Tighten securely
6.  Place device in line with existing
cable on either side of the coverter
box and connect to television set with
the short piece of RG59 coaxial cable.
Set television set to HBO channel
7.  Using a plastic screwdriver (non-matalic)
adjust the varible capacitor until picture
tunes in. Sit back, relax, and enjoy!!!