Ham Radio Projects by KM6AB

Mike builds, designs and tests experimental projects and has written many articles about his creations. On this page we present antennas that Mike has built and published for the Ham Radio Community. Hope you enjoy his material and have fun building these projects.

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The 4-bay VHF dipole array is about the best VHF omni antenna you will encounter with the most gain for its size that any other antenna design I know of. The novelty of this design is the simple PVC pipe arms that hold the dipoles out from the mast and fat copper elements for wide BW. The NVIS antenna pdf is sort of a sales brochure for portable maypole type HF antennas and can be used as in inspiration for people to build and improve on the design. It has a 1:1 choke balun on the HF side and its a resonant dipole on 40, 60 and 80m (jumper on the 80m leg for 60m) and I also made up some TV twinlead with BNC connectors for all band use with a tuner. This version also has an NMO mobile mount on top with screw in ground radials stowed in the body along with guy stakes. You pull up on site, transfer your mobile antenna to the fixture and when done you can work all bands 80m through 10 plus whatever your mobile antenna does but now its up higher on a mast.

Low Cost, High Performance

VHF Dipole Array

by Mike Frye, KM6AB

This project will provide you with a VHF high band antenna that can be adjusted for an omni directional pattern with 6dB gain over a dipole or a directional pattern with 9dB of gain. The antenna has upwards of 20MHz band width at the 2:1 VSWR points which will cover the 2m amateur band through RR frequencies and higher, or about 142 to 162MHz.

The key design criteria for this antenna was to use common hardware store components and repeatability so the builder . . .

read full article in pdf file format (includes all text and images)

Built for 142 to 162MHz

Mike's Tower

Mike Frye, KM6AB

Here are of some antennas we use, its hard to see them all due to the limited view:

From left to right on the tower cross bar is a 9dB VHF high band 4-bay dipole array (Maxrad);

Then there is a 10dB 900MHz stick,

a Sinclair VHF 4-bay dipole array on the tower face towards the viewer,

an A/S 8-bay UHF dipole array on the right side tower face,

a 2-bay 6m dipole array on the right tower face,

a KRECO 100-800MHz Discone,

and finally a military 4-bay 225-400MHz omni.

Higher up on the tower is another 100-800MHz Discone,

one end of my 94ft ZS6BKW dipole,

a100-1300MHz Log Periodic,

and an AMRAD VLF-HF E field active receive antenna at the top.

In the background is a Comet CP62 5/8 over 5/8 6M vertical,

a Harris RF-9070 90 to 470MHz Bicone,

and a Dressler active VHF/UHF receive antenna.

Image is clickable to a super huge photo!

Whew, that's a lot of metal in the air!

The tower is 35ft of Rohn 25 with a 20ft cross bar made of the same tower sections.

The project started out with eight runs of Andrew 1/2" Heliax to the tower via 35 feet of commercial 18" wide aluminum cable tray to the base of the tower.

And over the years the tray has filled with every kind of feedline and power cable to the various antennas.

Mike Frye, KM6AB

May 3, 2014