KU6X John F. Hurst Upland, CA QCWA # 23792 Chapter 177

I've been licensed since I was 13. My original call was K6SMD when I lived in Covina. My main interests have always been toward the techanical end, I'm a retired EE, and enjoy building equipment.

I've been building my own gear before I was licensed and have been collecting Military, home brew and unusual ham gear for the last 30 years or so.

Now that we no longer have channel-2 TVI problems I've discovered the magic of the 6 meter band.

My latest project has been to design a 6 meter modificaion to my Cushcraft A4-S tribander. After several months of antenna modeling (using Eznec 5+) I've come up with a design that works very well. It uses a "coupled resonator" horizontal driven element with a reflector and 2 directors. This isn't a new concept, it's been described in QST (see W1ZR) and it's been used in a number of commercial designs.

This design uses 1/2 inch aluminum tubing with PVC fittings and hose clamps for attachment to the boom. The second director is supported by a 24 inch piece of PVC pipe inserted in the front of the A4's boom.

I also added a three element vertical beam using 1/2 wave elements above the boom to minimize the coupling to everything below it. The vertical beam has its own feed line and there's esentially no interaction between H and V operation. You can see some of the details here:

I've found that having vertical polarization capability is almost necessary for local operation here in S. Cal. On single-hop Es horizontal polarization is usually best (polarization is maintained) but on double-hop Es the vertical beam can be several S-units stronger.

My next project is to add 6 meters to my SB-1000 using a vacuum relay to switch the 3-500Z plate to either the original HF Pi output or to a seperate 6M pi output. This should allow me to get high effeciency on 6 w/o sacrificing the HF effeciency.

Main complaint for us retired hams: "So many projects so little time".

73, John

January 1, 2015