Low Band Coil for Glass Fiber Mast Vertical Antenna

This is a low band coil (similar to those from buddipole) to get on 80 and 160m with a wire on an 8m or 10m glass fiber mast (fishing pole). There are different rings for different mast diameters. It was desgined for 0,8mm wire, but I used regular 1.5mm² electric wire with the insulation removed.

I used 3,5x16mm wood screws to fix the posts and m5 screws with wingnuts to connect the the radiator and the 20m elevated radial. The is connected using a SO239 connector.

Since this is an asymetric antenna, a 1:1 Balun or choke, or a couple of windings to form a coil right after the antenna connection is recommended.

I can not recommend a radiator length, since I simply hooked up a random wire that fit my 8m mast, tuned it and it worked. There is room for improvement by doing proper calculations and radiating pattern analysis in XNEC2 or MMANA so I leave you to play with this.

Since this is a shortened antenna, the bandwidth will be much narrower than on a regular half wave.

Lower frequencies, I provided a stackable soil spool that can go on the top of the lowband coil and connected using the M5 screw. The radiator will then be connected to the additional coil. This coil was not necessary for 80m, so I did not wind one.

I recommoned using an antenna analyzer or VNA for finding the best clip position on the coil.

As always I included the FreeCAD files for you to play with.