At our November meeting, SPARC members shared the antennas they use to get on the HF bands at home. Here are a selection of pictures and comments on each antenna.
Chameleon Emcomm II
The antenna is pointed northeast but is not very directional. It handles 200 watts on SSB, 100 watts on digital. Thanks to its 5 to 1 coil, the wire is resonant on 20, 40, 80. Using the antenna on 30 and 80 requires a tuner. The tripod was purchased on Amazon and spray-painted matte black to blend into the environment.
Comet CHA-250B vertical
The Comet is mounted on a pole attached to the garage on a hinged base so it can fold it down if conditions are windy. The antenna is self-contained, requiring no radials. It receives impressive DX like Brazil, Japan and Australia. However, it picks up a fair bit of noise too. A key advantage is its small, unobtrusive footprint.
MFJ Mobile Ham-tenna Whips
This is a pair of MFJ “HF Mobile Ham-tenna Whips” on a back-to-back bracket, forming a dipole configuration. The pairs of whips are tuned to a single band [10, 20, 40m] and do a good job. The bracket and whips are mounted on a fiberglass push-up mast with a tripod base. It provides the benefits of a dipole without requiring a support in, say, the neighbor’s tree. Tuning for a low SWR requires adjusting the whip length with an Allen wrench.
29’ random wire
In the box is a 9:1 UNUN that is meant for a “random” wire. The antenna is designed not to be resonant on any particular ham frequency, and it requires an external tuner to provide acceptable SWR from 6 to 40 meters. Build instructions are available in this PDF.
Although the instructions call for a random wire, it is necessary to avoid certain wire lengths so that the antenna is not accidentally resonant on any particular frequency. Here is a chart of safe wire lengths.
NA4RR Hexbeam
The NA4RR Hexbeam covers 20m through 6m. The most difficult issue was getting it mounted on the mast. The second issue is aligning the antenna direction with the rotor control direction.
Cushcraft R7
This Cushcraft R7 is mounted at about 33 feet, covering the 10, 12, 15, 17, 20, 30, and 40-meter bands. The 40-meter band performs best. The 20-meter band has been somewhat limited, the 15-meter band challenging, and the 10-meter band works occasionally. Here are a few links for further reference:
- Cushcraft R7 Setup at VE3XYD QTH
- Cobweb vs. Cushcraft R7
- eHam Reviews of the Cushcraft R7
- Cushcraft R7 Antenna Assembly and Installation
Cushcraft A4S Yagi
This Yagi works on 10, 15, 20, and 40. It reaches essentially anywhere on earth, even the South Pole. The element lengths are 20 feet long, spaced 10 to 15 feet apart. It’s mounted on a Tri-Ex crank-up tower, requiring no guy wires, that nests down to 23 feet. The tower is just over 60 feet tall when fully deployed. There are rotators on both the tower and the Yagis on the chimney.
Halloween Special Event Update
Our October 31 special event station W6H was a fun night of operating, even though our location didn’t have the best propagation. Here is a map of our contacts, and check out a few photos posted on our Instagram account.