Home | 1969 Chevy Truck | Dukes Of Hazzard | Links

How to Build a Teardrop Antenna
Using a Radio Shack 21-940a cb antenna for parts.

What to start with...

NOS Radio Shack 21-940a CB Antenna magnectic base "Teardrop Antenna Kit" consists or teardrop base, gasket, coax cable, mounting bracket, & allen wrench 21-940a out of the package: consists of magnetic base assembly, coax cable, lead coil, spring assembly, whip, & allen wrench

Start by peeling off the protective foil that is glued to the bottom of the 21-940a magnetic base. Next, remove the flat nut from the threaded sleeve on the top side of the base... ...then remove the threaded sleeve from the base.

After removing the sleeve, you will see the coax connector through the base. Flip the assembly over and remove the magnetic bracket/coax assembly from the base. The coax cable is still running through the base, so you can do one of two things. You can either break the base and remove the cable that way or you can carefully remove the connector from the end of the coax cable using pliers and a wrench.

I chose to remove the connector from the coax cable. Carefully pull the two apart and remove the cable from the base. Now, sit everything for the 21-940a antenna off to the side and grab the bracket/coax assembly that was supplied in the teardrop kit. Carefully grind off the rivet that attaches the ground wire to the bracket. (if you want to, you could just cut the wire instead) Now, back to the coax cable/connector that you just removed from the magnetic base... re-assemble the coax cable connector and crimp it with a pair of pliers or vise grips. If you chose to break your magnetic base, then skip this step.

Slip the 21-940a coax/connector into the bracket that was supplied in the teardrop kit and route the coax cable as seen in the photo. Put the coax/bracket assembly inside the teardrop base... ...and then screw the threaded sleeve onto the coax connector and tighten it down. Be careful not to over tighten the sleeve or it will cause the teardrop base to crack.

Re-apply the flat nut that came in the 21-940a antenna. Again, do not over tighten this nut either. Next, get the lead coil from the 21-940a antenna and screw it onto the base assembly... ...then it should look like this.

Now place the whip into the spring assembly and tighten it down with the allen wrench that was provided. Now for the gasket that is supplied in the teardrop kit... place it in a bowl of water and heat it up in the microwave for about 30-40 seconds. While the gasket is still warm and soft, place it on the bottom of the teardtrop assembly. Be careful not to over stretch the gasket. If you cannot get it on the first time, just heat it up and try again. Do not get the gasket too hot or it will lose it's shape.

This is the finished product... now all you need is a General Lee to mount it to!

This page was created on November 25, 2003

What to start with...

NOS Radio Shack 21-940a CB Antenna magnectic base	"Teardrop Antenna Kit" consists or teardrop base, gasket, coax cable, mounting bracket, & allen wrench	21-940a out of the package: consists of magnetic base assembly, coax cable, lead coil, spring assembly, whip, & allen wrench

Start by peeling off the protective foil that is glued to the bottom of the 21-940a magnetic base.	Next, remove the flat nut from the threaded sleeve on the top side of the base...	...then remove the threaded sleeve from the base.

After removing the sleeve, you will see the coax connector through the base.	Flip the assembly over and remove the magnetic bracket/coax assembly from the base.	The coax cable is still running through the base, so you can do one of two things. You can either break the base and remove the cable that way or you can carefully remove the connector from the end of the coax cable using pliers and a wrench.

I chose to remove the connector from the coax cable. Carefully pull the two apart and remove the cable from the base.	Now, sit everything for the 21-940a antenna off to the side and grab the bracket/coax assembly that was supplied in the teardrop kit. Carefully grind off the rivet that attaches the ground wire to the bracket. (if you want to, you could just cut the wire instead)	Now, back to the coax cable/connector that you just removed from the magnetic base... re-assemble the coax cable connector and crimp it with a pair of pliers or vise grips. If you chose to break your magnetic base, then skip this step.

Slip the 21-940a coax/connector into the bracket that was supplied in the teardrop kit and route the coax cable as seen in the photo.	Put the coax/bracket assembly inside the teardrop base...	...and then screw the threaded sleeve onto the coax connector and tighten it down. Be careful not to over tighten the sleeve or it will cause the teardrop base to crack.

Re-apply the flat nut that came in the 21-940a antenna. Again, do not over tighten this nut either.	Next, get the lead coil from the 21-940a antenna and screw it onto the base assembly...	...then it should look like this.

Now place the whip into the spring assembly and tighten it down with the allen wrench that was provided.	Now for the gasket that is supplied in the teardrop kit... place it in a bowl of water and heat it up in the microwave for about 30-40 seconds.	While the gasket is still warm and soft, place it on the bottom of the teardtrop assembly. Be careful not to over stretch the gasket. If you cannot get it on the first time, just heat it up and try again. Do not get the gasket too hot or it will lose it's shape.

	This is the finished product... now all you need is a General Lee to mount it to!