HAM RADIO ANTENNA

4 Band HF Dipole Antenna by K0RWU

This antenna consists of 4 resonate dipoles made from #12 insulated copper electrical wire. The dipoles are resonate on the following bands: 6 meters, 1Ø meters, 12 meters and 17 meters.

This antenna is resonate at 5Ø ohms, and requires no tuner on most bands. On 1Ø meters it is good in the SSB portion of the band, but will not work above 28.9 without a tuner.

The dipole is mounted at about 35 feet off the ground. It is suspended with nylon twine, between a mast mounted on my roof, and a back yard corner tree, some 4Ø feet away. I used small pulleys at the tree, and on the mast, so I could lower the antenna if needed.

The antenna was mounted and tuned at a lower level, and then raised to it's present position. Raising it changed the setting only slightly.

The 4 Band Dipole Mounted in the Alignment Position

Here, for alignment purposes, the antenna is suspended between the corner tree and my 16Ø meter antenna, at about the 15 foot level. I used a step ladder to get to the antenna ends, for trimming. Remember to move the ladder away from the antenna area when checking VSWR.

The Center Insulator and Feed Point

Shown here is the center feed. Any insulator would do, as the resistance and voltage are low. I used a Van Gordon insulator, so I could connect directly to a PL-259 on the feed-line.

To separate and evenly spread the antenna elements, I cut up a couple of 1Ø foot pieces of PCV refrigerator water line, and drilled them for the wire elements to pass through.

The separators are held in place with short pieces of #14 un-insulated electrical wire wrapped around the antenna wire and separator.

The Six Meter Element End

The six meter element is on top, because it is shortest, and lightest, and to mount it next to the 17 meter element. The 17 meter element supports the antenna, so it has end insulators.

I don't recommend supporting the ends with wire and insulators. If possible use nylon twine or rope, and if possible, keep the antenna ends away from metal objects.

The 1Ø and 12 meter element ends

The 1Ø, and 12 meter elements, are mounted below the 17 meter element, with the 12 meter element next to the 17 meter element. This arrangement look nice, and balances the antenna.

A small amount of the 6, 1Ø and 12 meter elements extends past the spreaders for alignment purposes. Alignment of the 17 meter antenna involves re-wrapping the wire ends on the insulators, if you cut it too short, you can wrap and solder some short pieces off the ends at a point before the wire wraps around the insulator.

Personal Commits and Tuning
This antenna works quite well. Because the 17 meter's third harmonic is 54 mhz, there may be some 6 meter gain obtained from coupling.

I recommend painting the spreaders flat black to help protect them from sunlight, and help hide the antenna. I spaced the spreaders out about every 18 inches. I spaced the elements 2 inches apart on the spreaders. You can space the elements anything over 1 inch, but they must be uniform.

Element lengths are measured from the center insulator support eyelet to the end. I started with these lengths, and checked VSWR, and tuned each element in the following order: 17 meters= 13 feet, 12 meters= 9 feet 6-1/2 inches, 1Ø meters= 8 feet 5-1/2 inches, and 6 meters= 58 inches.

To tune each element to my favorite frequency, I then clipped each dipole at both ends, 1/4 to 1/2 inch at a time, checking VSWR every time. Then, re-check all elements in order, and re-tune if necessary.