Television stations broadcast their signal "over the air" to surrounding areas. TV antennas are designed to receive the signal broadcasted by the transmitters. Picture quality depends on the type of the antenna and the distance from the transmitter. The further you are from the transmitter, the worse the picture becomes. TV broadcasting is a point to point communication. Any obstructions between the transmitter and the antenna will degrade the signal strength, affecting the picture quality.
There are three bands of frequencies broadcasted by the television transmitters regulated by the FCC Rules and Regulation, Part 73:
|2-6||VHF low band 54-88MHz|
|7-13||VHF high band 174-216MHz|
Each Channel requires 6MHz, i.e. channel 2 utilizes 54MHz to 60MHz, channel 3 utilizes 60MHz to 66MHz, etc. Signals in UHF band dissipate faster over distance than VHF signals. To make up for the loss, transmitters operate at higher power in the UHF frequencies than the VHF. Also, antennas are designed to provide more gain on the UHF frequencies.
Maximum radiated power allowed is:
|14-69||5000 Kilowatts (limited to 1000 kilowatts within 250 miles of Canadian borders)|
|* Source: FCC Rules and Regulations, Part 73|
The Signal Commander antenna is designed to receive and amplify the TV signals (channels 2-69). The amplifier is mounted directly on the antenna elements. A 75 Ohm coaxial cable is used to bring the signal from the antenna to the wall plate inside the RV. The same cable provides the 12V DC to the amplifier. There are different models of wall plates available to support: one TV, two TVs, cable ready, and satellite ready. A splitter is used to operate two TVs. When a splitter is used, the signal is reduced by 30%, but is available to two TVs. If you are using only one TV in your RV, select a wall plate without a splitter to minimize the signal loss in the system. Coax Cable length also affects the signal loss. A longer cable results in more signal loss, especially on the higher frequencies.
There are no monthly fees to pay, making the antenna the most economical option for television reception.
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All products are made in our facilities in Longmont, Colorado. Each assembly is tested to assure reliable operation and specification compliance. Selected at random from the production line products go through extensive tests to evaluate the life expectancy.
Testing for water leaks
There are two “o-rings” installed in the lift assembly to prevent the water from leaking inside the Vehicle. The “o-rings” are compressed .010”. This compression will hold more than 50 lbs. positive pressure without a leak. The antenna should pass a 2,250 cycle test without any leaks.
The Antenna is mounted on a table inside a pan. Water is poured in the pan until the water level rises to 3”. At this point the installation is checked for water leaks. For the next two weeks the antenna is raised and lowered 2,250 times, always checking for any water leaks. After the 2,250 cycles are complete the antenna is taken apart and each part is evaluated for wear and tear. Information gained from the stress tests is used to design better parts with better material.
Testing the Gears
The antenna is mounted on a table. A special platform is attached to the upper pivot instead of the head assembly. The lift assembly is raised until the upper pivot is 18” above the table. The platform is then loaded with pieces of steel. (The Head Assembly’s weight is 2.25 lbs.)
When the total weight on the platform reaches 39.8 lbs. the worm gear breaks. Since the platform is 3 feet away from the point where the gears engage this translates to 39.8 x 3 = 119.4 ft lbs. This number is 17.7 times the pressure applied when the antenna head is installed.
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