ZipZap SE Antenna Modification

Introduction

click on the image for a larger view	This article provides instructions for changing the stock antenna on a ZipZap SE car to a removable "whip"-type antenna. The object is to replace the limp, aesthetically unpleasing yellow antenna with a solid, vertical antenna which may be cut to the proper frequency, if desired. Further, the antenna is designed to be easily unplugged from the car for transportation or repair. I think the CAT5 mod has the right idea. My modification takes that idea one step further, making the antenna just a bit more versatile. If this modification or the CAT5 mod is more than you can handle, at least use the plastic straw method to keep the antenna up in the air.

The following parts are required:

a 6-inch or longer piece of .020-inch diameter brass wire
one pin and one socket from a d-type connector set

The brass wire is usually available at hobby shops which sell model plane and railroad items. It can often be purchased in 12-inch lengths for around $0.25. The connector parts are available at Radio Shack and come in 9-, 15-, and 25-pin configurations. You will need to purchase both the male and female versions of the connectors. The 9-pin connector set is adequate to modify several cars with enough left over to build spare antennas. The Radio Shack part numbers are given below:

9-pin male crimp-type d-sub connector, part number 276-1427
9-pin female crimp-type d-sub connector, part number 276-1428

If you want to share this modification with your friends, consider purchasing one of the two larger connector sets.

Tools

If "modding" ZipZaps or other small RC cars is as much fun for you as is running them, then you already know that a tool box filled with the right equipment is very helpful. If you don't have those necessary instruments, then now is a good time to start building that collection of tools. I've been model railroading for about thirty years, have built up a good set of tools, and never have spent a large amount of money on any of them (big items, like a Dremel tool, came as Christmas gifts--take the hint). Most of them, if not lost, have lasted over the years and served me well. That said, the tools needed for this project are: small Phillips screwdriver small wire cutters Dremel tool, or equivalent, with cut-off discs small pliers or a small vise soldering iron and small diameter rosin-core solder two jeweler's files, one round and one flat patience

Remove the Existing Antenna

Remove the body from the chassis and set the body aside. Remove the plastic clip which holds down the back of the printed circuit board (PCB). Grasp the knotted end of the antenna wire and pull it through the small hole in the plastic clip. Set aside the plastic clip and its retaining screw. Untie the knot in the antenna.

Building the New Antenna

1. Trim the Connector Pins.

a. With a cut-off disc in a Dremel tool or a pair of wirecutters, and holding a solid part of the connector with pliers or in a vise, remove the wire attachment part of both the pin and socket.	b. With the flat side of the cut-off disc or a flat jeweler's file, again holding the connector with a clamping device, smooth the ends of the connectors from which the wire attachments were just removed.

2. Assemble the "Whip".
Note: This connection must be soldered to maintain electrical continuity. Adhesives like Super Glue will not work!

a. Insert a piece of small-diameter solder into the end of the pin. b. With a soldering iron, heat the small end of the pin until the solder melts and flows into the pin.	c. With the soldering iron still applied to the small end of the pin, insert the brass wire into the pin, slowly pushing it in until it stops. The solder inside the pin will be adequate to capture the brass wire. d. Remove the soldering iron and leave the soldered antenna whip until it cools.


3. Assemble the Socket.
Note: This connection, too, must be soldered to maintain electrical continuity. Adhesives like Super Glue will not work!

a. On the plastic clip which holds the PCB, locate the small hole through which the original antenna passed. With the round jeweler's file, slowly enlarge that hole until the connector socket press-fits into the hole. b. Replace the plastic clip, without the connector socket, screwing it securely to the chassis. c. Route the antenna wire to the hole where the connector socket will be located.	d. With the antenna wire in place, cut the wire to a length just a bit longer than needed to reach the hole. e. Carefully strip the insulation from the end of the wire, then "tin" the bare wire with the soldering iron and a very small amount of solder. f. With the connector socket removed from the plastic clip, "tin" one side of the socket in the bifurcated area. And then, with heat applied to the socket, solder the wire to the socket, being very careful not to let solder flow into the inside of the socket. g. When the wired socket has cooled, press-fit it into the hole in the plastic clip.

Reassembling Your ZipZap

1. A New Hole for the Antenna.
Without the "whip" plugged in, place the car body on the chassis. Spend some time contemplating where on the body the place is that is just over the socket. Mark the body at that place, remove the body from the chassis, then drill a small hole at that mark. With the round jeweler's file, slowly enlarge the hole to a diameter which will pass the connector pin attached to the whip.
2. "Tuning" the Antenna.
If you really wish to drive your car with a foot-long antenna, plug it in and give it a try. I'd recommend a six-inch antenna--just measure the whip to length and cut it. The bulge on the connector pin reminded me of the loading coil on a CB antenna--I painted mine flat black. Upon some reflection, I think my next project will be building a loading coil--may I can make a two-inch-long antenna "look like" thirty inches to the transmitter! Obviously, the .020-inch diameter brass whip will bend. Do it if it suits your style, but remember that typically vertical antennas are more efficient in this configuration.

Just in case you wondered, this '77 Firebird has been raised in the back and lowered in the front. The windows have been "tinted" and dual exhausts (brass tubing) fabricated and added. Extended rear fender flairs were also installed over the wide tires. If you have questions, contact me at censusia@stroxel.com. Gene Crossett, Jr. Terre Haute, IN January 22, 2005