N3CRK builds an antenna for an FM stereo receiver


A friend needed a good antenna for his FM stereo receiver.
FM stations have been transmitting both horizontal and vertical polarities since FM car radios became common.
I decided to build him a 75 ohm vertical coaxial antenna for 98 MHz, the center of the FM band.
It took me about an hour to build it. Here is how I did it.



The materials: 5' length of 1" schedule 40 PVC pipe.
2 caps for the 1"PVC pipe.
3/4" copper pipe at least 28 5/8" long.
1 copper cap for the 3/4' copper pipe.
1 chassis-mount female "F" connector.
Enough RG59, 75 ohm coax to reach from the antenna to the radio with a male "F" connector at one end.
At least 28 5/8" of stiff wire. (Not shown in this photo.)


Step 1: Connect the coax to the chassis "F" connector. Use two 7/16" wrenches to make it slightly more than finger-tight.
Step 2: Drill a 3/8" hole in the copper cap to fit the "F" connector.
Step 3: Drill a 17/32" hole in the PVC cap to fit the coax. You can drill a 1/4" hole and file it to make a snug (but not tight) fit for the coax.



Step 4: Attach the chassis "F" connector to the copper cap. Make it tight but don't strip the threads.
Step 5: Cut the copper pipe to 28 5/8".
Step 6: Slide the coax through the copper pipe.
Step 7: Tack solder the copper cap to the pipe.



Step 8: Cut a piece of stiff wire (I used #14) to 28 5/8" and solder it to the center conductor of the chassis "F" connector.
You should now have this much done.



Step 7: Slip the antenna into the PVC pipe. Slide the drilled cap over the coax and onto the pipe



Step 8: Put the remaining cap on the other end of the pipe and you are done.
Of course mount the antenna, route the coax to your FM radio and connect it.