anickode
04-29-2013, 04:19 PM
And what better to start with than a 1/4 wave center loaded large coil?
http://i292.photobucket.com/albums/mm9/anickode/20130429_173158_zps34f781ef.jpg (http://s292.photobucket.com/user/anickode/media/20130429_173158_zps34f781ef.jpg.html)
The overall length is 58", and the overall element length is 54. The coil is 5 turns, 3.75" dia by 3.75" long. Hope my math came out right. The insulator is 3/4" SCH80 pvc, with 1/2" NPT threads tapped into the ends. The bottom of the coil is soldered into a 3/8" hole drilled in the side of the threaded adapter. The top of the coil is soldered into a 3/8" hole drilled into the side of a 1/2" NPT to 5/8"OD compression fitting (1/2" copper pipe is 5/8" OD). After the coil was soldered in place, I ran a 5/8" drill bit though the compression fitting, cutting the stub of copper from the coil off flush with the inside of the fitting, and removing the stop lip inside the fitting, allowing the top half of the antenna to slide freely in and out up to 4 inches for tuning purposes.
Guess we'll see if it works. If not, at least it looks cool.
http://i292.photobucket.com/albums/mm9/anickode/20130429_173158_zps34f781ef.jpg (http://s292.photobucket.com/user/anickode/media/20130429_173158_zps34f781ef.jpg.html)
The overall length is 58", and the overall element length is 54. The coil is 5 turns, 3.75" dia by 3.75" long. Hope my math came out right. The insulator is 3/4" SCH80 pvc, with 1/2" NPT threads tapped into the ends. The bottom of the coil is soldered into a 3/8" hole drilled in the side of the threaded adapter. The top of the coil is soldered into a 3/8" hole drilled into the side of a 1/2" NPT to 5/8"OD compression fitting (1/2" copper pipe is 5/8" OD). After the coil was soldered in place, I ran a 5/8" drill bit though the compression fitting, cutting the stub of copper from the coil off flush with the inside of the fitting, and removing the stop lip inside the fitting, allowing the top half of the antenna to slide freely in and out up to 4 inches for tuning purposes.
Guess we'll see if it works. If not, at least it looks cool.