The WG3J Double Bazooka

 

The original design by M.I.T.  Was to produce an antenna for radar use at the time and it was adapted to amateur use and has been very successful in amateur use over the years.

 

The Double Bazooka is made from a half wave wave coaxial stub with the balance of the dipole length made from a single wire, or preferably from 450 ohm open line or a cage wire section using spacers and several wires.

 

The two latter methods will yield much broader band response in most cases covering nearly an entire amateur band from top to bottom with no tuner required.

 

The formula for the coax dimension is 325/f Mhz

 

The total antenna is 460 divided by the free in megahertz. On the low bands use of RG-58U is the best choice due to the length and weight of the cable.

 

For use on higher frequencies you can use any 50 ohm cable even RG-213 or RG-8 as the antenna. I typically use a single wire #12 or #10 for the end sections and it works very well...

 

For 1900 KHz the coaxial dimension is 171 feet and the wire section is 71 feet divided by 2 or 35 feet six inches allow for connection and insulator tie off at the ends.

 

For 1800 KHz the coaxial dimension is 180 feet and the wire end sections are 37 feet 6 inches.

 

I use copper wire clamps of the appropriate size to connect the ends of the coax to the wire and solder and seal tape all connections.

 

Now for the center connection we in exact center of coax and remove about 4 inches of the jacker then carefully cut thru the braid only and fold back to make two pig tails for attachment of the coaxial feed line.

 

Do not cut thru the center dielectric or center conductor these must remain continuous, this is the secret to making the double bazooka broad banded together with the diameter of the coax (rf skin effect) makes the antenna diameter larger

 

There is a variant of the double bazooka called the cross connected bazooka that many people swear by and say it is even broader than the standard, the only difference is the center of the coax is cut, and it is cross connected center of left to braid of the right side, the braid of left side to center conductor of right.

Then these two pair is connected to your feed line.

 

I prefer the standard bazooka and have had much better results with the standard. This antenna is also in many handbooks for further information...   WG3J Eric