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Better Broadcast TV Picture Quality

Originally Published in MotorHome Magazine

Once the federal government mandated that television broadcasters switch to a digital signal, watching the tube for free took on a new vision. A clear vision to be exact. Until recently, there have been almost no changes in the way RVers capture a signal; using a rooftop batwing antenna was and is quintessential to the industry. King-Dome, a leader in dome satellites, has introduced the Over-the-Air Jack, which brings in crystal-clear digital signals and fits into the existing space occupied by the batwing antenna.

Recognizing the need for a much improved TV antenna, King-Dome set about building the JACK, a VHF- and UHF-amplified HDTV antenna that’s easy to install and simple to operate. The new JACK can replace the old crank-up antenna in about an hour. In general, there is no cutting, measuring or drilling as the JACK utilizes the existing hole as well as the existing coaxial cable that is left exposed after removing the batwing antenna. The toughest part of the job was removing the old antenna because the sealer holding it to the roof was firmly adhered and caution must be taken not to tear a rubber roof.

If your motorhome has never been equipped with any type of TV antenna, you will need to drill a 2-inch hole in the roof for mounting the JACK. The manufacturer’s instructions are clear and provide straightforward advice for those who have flat or pitched roofs.

Positioning the JACK so that the base faces the front of the coach is critical. It also needs to be positioned so that it centers the roof hole and is at least 20 inches away from any other object, such as an air conditioner. Doing so allows clearance for the JACK to rotate freely. Also, the center of the roof hole must be at least 8 inches from the edge of the roof. The roof thickness may vary from 1¼ to 6 inches and the roof pitch cannot be more than 3 degrees in order for the JACK to function properly. If the roof pitch is more than 3 degrees, a slightly larger hole (up to 2¼ inches) may be necessary so the shaft can line up properly. A longer connector is supplied if the roof is more than 3½ inches thick.

Before the JACK can be mounted to the roof, the original coax must be attached to the T-connector on the underside of the new antenna. The existing short coax cable is fed through the hole in the roof to be used later. Now it’s a matter of pulling the adjustable connector to maximum length and applying sealant to the bottom of the flange on the JACK base mount (butyl tape may also be used in most cases) and installing the screws. It’s important to seal all screw heads and around the base mount of the JACK to adequately weatherproof the new antenna.

Once inside the motorhome, the adjustable connector is pushed until the shoulder is flush with the ceiling. The small coax cable is connected after feeding down through the roof to the enclosure base, which is mounted with the supplied screws; the enclosure base may be mounted in any direction. Snap on the enclosure cover, install the rotation knob and the set screw. Remove the old power supply and mark the cables and wires (12-volt DC) and install them on the new power injector that is conveniently marked and in the same location.

To establish maximum signal strength, you simply push the power button, slide the switch on the enclosure base to the on position and rotate the attenuator dial fully clockwise. The antenna is rotated until the maximum number of LED lights are lit up. Then the attenuator dial is rotated counterclockwise until the last illuminated LED light flickers, and again to fully illuminate the last flickering LED light. Once that’s done, you just follow the instructions for TV or converter box and scan for available channels.

Before installation, the TV channel scan revealed 87 channels; once the JACK was installed we were able to acquire 101 in a matter of seconds. Granted, not all the channels were crystal clear, but the strong digital signals were impressive, producing a very nice high definition picture – for free. The approximate retail price is $140, and for that you get a chic-looking, compact antenna that offers superior reception.

For More Information:

King Controls, 952-922-6889, www.kingcontrols.com.

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