From: mjohnson at netcom4.Netcom.COM (Mark Johnson)

If you know what you are doing, you can build wirewrapped
boards that operate above 100MHz.  I myself have done so;
I've got a couple that run at 150MHz with no trouble.

On the other hand, if you don't know what you are doing,
you can screw up almost any technology, including wire
wrap, printed circuit board, proto-plugboard, and airbridge.

   "It's not the sword, it's the swordsman"
   "It's not the sword, it's the swordsman"
   "It's not the sword, it's the swordsman"
   "It's not the sword, it's the swordsman"

Here are a few ways to screw up a wirewrapped project,
so as to make it fail even at low frequencies:

   1.  Don't use a board with a ground plane.

   2.  When wrapping the positive and negative supply
       pins of IC's, use wires longer than 0.75 inch.
       The longer the better; these aren't high
       frequency signals, they are just DC supplies.

   3.  Don't install ceramic bypass capacitors at
       every chip

   4.  Use digital logic chips having very fast
       edge speeds (dV/dt), such as 74S, 74AS, 74F,
       and, best of all, 74FACT.

   5.  Daisy chain the ground wires: wrap from the
       off-board ground connector, to the ground pin
       on the first chip, to the ground pin on the
       second chip, to the ground pin on the third
       chip, and so forth.

   6.  Freely mix analog and digital circuitry on
       a wirewrap board,  Be sure the analog part
       us used as a routing area for digital signal
       wires, and vice versa.  Share supply and
       ground connections between the two.

If you scrupulously follow these rules, then you can
brag to your friends that you have built a wirewrap
board that failed, not at 20MHz, but at 1MHz.  Won'tthey be impressed!

  .