Antenna Selection for Rovers

Antennas can be one of the most challenging and controversial aspects of roving. It all depends on your location, population destiny, terrain, bands and what you want to accomplish.

• If you plan to rove relatively near to high ham population areas and know of good operating locations then omnidirectional antennas work fine.
• If you plan to rove on the fringes of civilization then you may need more gain from your antennas.
• If you plan to operate while in-motion (with a driver buddy at the wheel) then you'll be interested in the omnidirectional antennas and/or limited turning radius directional antennas with a rotor.

Its recommended that you start your roving career located near high ham population areas so as to not get totally discouraged and experience what it takes (in terms of equipment and operator experience) to make QSOs from a rover.

The "Dish" Bands (5, 3 cm and 12 mm) are dominated by dish type reflectors with varius feeds:

Several vendors sell both the dish reflectors and single / dual band feeds. More information here.

There are many DIY instructions available for conversion of these satellite TV dishes for 10 GHz use.

• Check out K0AWU/s DSS feed here.
• W1GHZ 10 GHz link here.

The "Looper" Bands (33, 23, 13 and 9 cm.) are a challange for cost effective rover antennas:

Regular Yagis are available for the 33 and 23 cm bands but loop Yagis are feasible stating with the 33 cm band. Either will give you good results with relatively high gain for 6' long booms. "H" frames are popular for mounting multiple loopers onto a single boom. Transmission feedline losses become significant at these frequencies so use good, short feedline or you will have wasted your investment in a good antenna.
More loop yagi information here.

The "Yagi" bands (2, 1.25 and 0.7 meters) offer many alternatives for effective rover antennas:

Over the years I've tried many different antenna designs for these bands.

For local use horizontally polarized, omnidirectional antennas can work fine and have the advantage of not being directional (you don't have to aim them).

However, as you begin to venture away from ham population centers you'll usually need a directional antenna in order to work the more distant and/or weaker stations (and point away from local noise). The Yagi is one of the most popular antenna designs for these bands. It's available in narrow, wide and multiple band designs.

The log periodic Yagi is a medium-gain, multi-band antenna requiring minimum mast space. That is, you can have multiple bands on a single antenna boom.

Single band Yagis are also popular rover antennas offering higher gain per band. There are many DIY designs on the Internet as well as commercial kits available.

• More information here.
• DIY information here.

The Quad is another popular roving alternative that can be made into single or multiband versions. The gain is similar to Yagis but the winload and mechanics are more challanging.

The 6 meter band is one of the more difficult bands for an effective rover antenna:

• The physical size of an effective 6 meter antenna can be overwhelming to mount onto a rover vehicle.
• Taking advantage of the horizontally polarized "ground bounce" and reducing the atmospheric noise arriving from high radiation angles requires that the average height of your antenna one wavelength or more. This can be difficult to achieve on a rover vehicle.
• Pointing away from local noise sources (power lines, buildings, etc.) requires a good front-to-back ratio which also adds to the size of an antenna.
• Wind loading and additional weight (at the top of your mast) may over stress your mast when traveling at high speed.

Any antenna is better than a dummy load so go out and try something so that you have a point of comparison. Even a vertical will give you some contacts with the locals.

Over the years I've come to appreciate two types of horizontal antennas for 6 meter roving:

• A one to three element quad antenna has a narrow physical width, lower noise sensitivity and forward gain (with 2 - 3 elements) when in a "quad" configuration.

• The stressed moxon antenna is a good compromise with a low weight and wind load together with forward gain.

Note that you must properly decouple the feed line for best results with both of these 6 meter antennas. Higher is better!

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