Sometimes, a long whip doesn't seem to be long enough. This could be due to a number of reasons caused by the position of the whip on the vehicle. For example, I've seen whips mounted inside the walls of a pickup bed. Even when using a spring to make it 108", if it ever appears to be short, here's something you can do to make your whip as long as needed.
[/u]Parts List
1 pc 3/4" copper tubing 3' feet long
2 ea 1/2" X 1/8" Brass busing
1 tube JB Weld
Rivet gun and rivets (Optional)
Parts available at Home Depot and other outlets.
It so happens that those little bushings are threaded at 3/8" X 24 TPI and your whip will screw right down into them. Makes these handy for lots of antenna projects. The bushings will pop right into the ends of the 3/4" copper tubing--usually quite snugly. Select a length the antenna *seems* to want. You should be able to trim this lower mast with a hacksaw, removing one of the bushings until the whip and mast are the right length. When the SWR is satisfactory, secure the bushings inside the tubing with JB Weld. After the JB Weld has set up, then you may want to drill and rivet these ends in place. Also you may find it necessary to dress the bushing threads with a 3/8" X 24 tap for the whip. You can then assemble the antenna, mast and spring (if needed and is part of your equation) and VOILA! You can even paint this mast to match.
I have made these things for years and you can also make homemade "coily" antennas using this method, making the mast as long as short as needed.
Hope this helps!
CWM
[/u]Parts List
1 pc 3/4" copper tubing 3' feet long
2 ea 1/2" X 1/8" Brass busing
1 tube JB Weld
Rivet gun and rivets (Optional)
Parts available at Home Depot and other outlets.
It so happens that those little bushings are threaded at 3/8" X 24 TPI and your whip will screw right down into them. Makes these handy for lots of antenna projects. The bushings will pop right into the ends of the 3/4" copper tubing--usually quite snugly. Select a length the antenna *seems* to want. You should be able to trim this lower mast with a hacksaw, removing one of the bushings until the whip and mast are the right length. When the SWR is satisfactory, secure the bushings inside the tubing with JB Weld. After the JB Weld has set up, then you may want to drill and rivet these ends in place. Also you may find it necessary to dress the bushing threads with a 3/8" X 24 tap for the whip. You can then assemble the antenna, mast and spring (if needed and is part of your equation) and VOILA! You can even paint this mast to match.
I have made these things for years and you can also make homemade "coily" antennas using this method, making the mast as long as short as needed.
Hope this helps!
CWM