UHF communications antennas are also sometimes used for specialized requirements. However, such antennas are usually narrow band and must be modified to function properly in the 494 to 608 MHz and 614 to 806 MHz ranges. Contact the Vega factory or your sales representative for assistance in selecting antennas for unusual applications.
Antenna Placement
No matter what type of antenna is used, care must be used in positioning and mounting. In all cases, a clear and unobstructed line-of-sight path between the receiving antenna and the transmitter is required. The receiving antenna may be concealed behind fabric, thin plastic, acoustic tile, and thin plywood without significantly affecting performance. However, close proximity to metallic objects such as furniture, lighting fixtures, scaffolding, electrical cables, metal structural members, aluminum window frames, and equipment cabinets must be avoided.
Whip and dipole antennas require at least a 5-inch (0.13-m) minimum spacing from metal surfaces. Other types of antennas may require greater spacings. The radiation pattern of these antennas is much larger than the antenna itself. Consequently, even objects well off to one side of the line-of-sight path can distort the antenna pattern, affecting performance. Also often overlooked are the effects of using metal brackets for physical mounting of the receiving antenna. Vega's magnetic-mount and ground- plane antennas are designed to mount on a flat metal plate and on an antenna mast, respectively, but many types of antennas are not. The manufacturer's recommendations should be followed when using Yagis and other types of specialized antennas.
The use of long cables connecting the antenna to the receiver is strongly discouraged. At UHF frequencies, the signal loss in the cable rapidly builds up and can seriously degrade operating range.