The NOGAnaut: Construction

The NOGAnaut is constructed "dead-bug" or "ugly-style." Unlike most kits with which you may be familiar, there are no holes to poke the component leads through the PC board. In this project, all components are soldered onto the same side of the board as the circuit traces. This is similar to "surface-mount construction" with which you may be familiar (there was a series of articles in QST, winter-spring 1999, on surface-mount construction if you are interested).

The reason this type of construction was chosen for this project is simple: it makes it much, much easier to make modifications to the circuit in the future. This kit is meant as a starting place for you to make your own modifications, and experimentation. Unsoldering components mounted through a PC board is much more difficult-in fact, the better made the PC board, the harder it can be to remove components (some "plated-through" boards make it down right impossible to remove components).

Looking at the PC board (see Figure 2), you will see that most of the board's surface is a ground plane. However, "islands" have been cut out of the board to provide places to solder circuit connection points together.

Notice also in Figure 2 that C1, C2 and C4 are shown with two capacitors, one slightly grayed out. In order to achieve the necessary capacitance for these circuit components, you may have to parallel two capacitors. For example, if you don't have a 750-pF capactor for C4, you can parallel a 680-pF and a 68-pF capacitor. There are other combinations as well, using standard value capacitors, such as 470-pF and 330-pF, 560-pF and 180-pF, etc. If you have a second capacitor, place it where the grayed-out component is shown in Figure 2.

Figure 2.  NOGAnaut PC board traces and parts layout.

Figure 2. NOGAnaut PC board traces and parts layout.

There are several ways to mount a part onto to the circuit board. The easiest is to cut the component leads to approximately inch, and then bend a very small part (about 1/16th to 1/8th of an inch) of the end of each lead perpendicular to the lead. For some components (such as resistors), you may have to bend one of the leads parallel to the part to fit neatly on the board. This is where you get to make decisions about how you want your board to look when you're done. Some suggestions are shown in Figure 3.

Figure 3.  Some suggestions on how to mount parts onto the PC board.

Figure 3. Some suggestions on how to mount parts onto the PC board.

Use a pencil soldering iron (say between 25 and 45 watts or so) to build the circuit. To solder a component lead to the board, first touch the tip of the iron to the place on the board where you wish to place the lead. After briefly heating the board, apply a small amount of solder, to make a small blob on the board. Put the solder down, pick the part up by the other lead with needle-nosed pliers and place the lead that you wish to solder to the board on top of the blob you just made. Then reapply heat touching the blob with the iron long enough to remelt the solder around the bent component lead. Finally, grab the lead with your needle nose pliers for about 20-30 seconds, to dissipate some of the heat away from the part.

This may take some practice--you can practice by soldering small pieces of component lead anywhere you'd like on the ground plane (the big open area covering most of the outer part of the board). Clip them off when you're done practicing-it is, after all "ugly" construction! It's not hard, once you get used to it.

Once you install the first lead of a component, installing the other lead(s) is easy-just apply a small amount of heat and solder to the appropriate place where the lead contacts the board, melt enough solder to hold it in place and remove the heat. Again, grab the lead with needle-nosed pliers for 20 or 30 seconds to help draw off excess heat and avoid damaging the component.

You can install the components in any order that you wish, however, we've found the following order of installation to be simple and straightforward.

  1. First, mount the transistor standing up, as is shown in Figure 4. Leave plenty of lead on the transistor. This will help to dissipate the heat as you solder (however, you can still damage the transistor by applying too much heat). It will also make it easier to remove, should you need to replace it in the future. Note the orientation of the tab on the 2N2222A transistor. The lead closest to the tab (the emitter) should be soldereed to the same trace as R2, C4 and C5.

    Figure 4.  The 2N2222A transistor mounted on the PC board using

    Figure 4. The 2N2222A transistor mounted on the PC board using "ugly construction."

  2. Next, mount the resistors, R1, R2 and R3. Pay careful attention to installing the proper value in the proper location, as shown in Figure 2. When you mount R3, be sure to leave just a little room for C5 that mounts between the emitter and base of the transistor. Refer to Figures 1 and 2 as you mount each component to be sure that each is placed in its proper location.
  3. Mount the capacitors. C3 should be mounted first, then C5, then C4, C1 and C2. Note that there is not much room to mount C5. Mount it carefully to ensure that you don't bridge the gap between circuit board traces with solder (known as a "solder bridge").
  4. Mount the inductors. You may need to install them "standing up" (one lead parallel to the inductor) depending on how much room you left yourself for these components. If you need to, you can always move a component lead slightly, by reheating the solder around the lead. Just be careful that you don't overheat the component.
  5. Install the crystal. Be extra careful mounting this component, as too much heat can damage it.
  6. Remove the grounding lug from the RCA plug and bend about 1/8th of an inch (up to the small hole) of the narrow end of the lug perpendicular, so that once soldered on the board, the lug stands straight up with the large opening on top. Solder it to the board as close as possiible to the edge, parallel with the edge, where indicated in Figure 2. Insert the RCA jack, and then install and tighten the nut so that the jack is held firmly in place. Note that the hole in the center connector of the jack should be directly over the "RF Out" trace on the PC board. It's best to tighten it such that the hole of the center connector of the jack is down; that is, it looks sort of like a "U" when looking at it on end. Now take an excess piece of component lead and solder it between the "RF Out" trace (the one where C1 and L2 meet) and the center conductor of the RCA Jack.
  7. Cut a 3" piece of the red wire on the 9V-battery connector and solder to the trace labeled "Key (+V)". Connect the other end of this wire to your telegraph key (or other switch) and connect the remaining red wire to the other pole of your telegraph key (or switch).
  8. Connnect the black wire to any convenient point on the ground plane (the large area around the perimeter of the PC board.
  9. Check over the entire board to ensure that all components were installed correctly, that there are no solder bridges, and that there are no loose connections.
  10. Install a 9V battery or connect to a 9-15V source.
  11. Connect a 50 ohm antenna to the RCA jack (unbalanced coaxial connection).
  12. Key the transmitter, and you should be able to hear your signal in a nearby receiver tuned to 3686.4 KHz (note that this could vary by a couple of hundred Hz or so-that's OK).

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Copyright ©, 1999, Mike Boatright, KO4WX (Copies may be freely made with attribution)