{"id":620,"date":"2011-01-12T19:08:41","date_gmt":"2011-01-12T19:08:41","guid":{"rendered":"http:\/\/ravtrack.com\/GPStracking\/?p=620"},"modified":"2011-01-19T17:29:38","modified_gmt":"2011-01-19T17:29:38","slug":"antenna-tuning-or-cutting","status":"publish","type":"post","link":"https:\/\/ravtrack.com\/GPStracking\/antenna-tuning-or-cutting\/","title":{"rendered":"Antenna Tuning or Cutting"},"content":{"rendered":"

Antenna Tuning or Cutting<\/span><\/p>\n

\u00a0<\/p>\n

Selecting and installing a proper antenna for a telemetry radio, GPS transponder, or base station\u00a0involves selecting a suitable style of antenna for your installation, properly mounting the antenna, cabling the antenna to the radio connection, and possibly adding a lightning arrestor to the antenna cable.\u00a0 One of the most important considerations is ensuring you select an antenna that works well for your operating frequency.\u00a0 In many cases this involves tuning the antenna for the proper frequency.<\/p>\n

Any antenna is constructed of a metal conducting element.\u00a0 Often this element is insulated from direct contact with a rubber or fiberglass sheath, or some other material and you will not see the metal element itself.\u00a0\u00a0 In any good antenna the shape and length of the element was carefully considered when the antenna was designed.\u00a0 Some elements are simple straight thin metal rods, others are coils, loops or other styles or combinations.\u00a0 Frequently the antenna is built to work at a very specific frequency or range of frequencies, such as 450-460MHz.\u00a0 If you select an antenna built for the wrong frequency you will have very poor results.<\/p>\n

Some common antennas allow for the user to adjust the antenna for their frequency.\u00a0 The antenna may be built to cover a wide range of frequencies, such as 400-500MHz, but should be adjusted to the precise user frequency.\u00a0 As radio transmissions are actually radio \u201cwaves\u201d you may remember that a radio frequency and radio wavelength are tightly related.\u00a0 Tuning an antenna typically involves adjusting the length of the conducting element(s) to be a specific ratio of the actual radio wavelength.<\/p>\n

Often field tunable antennas involve 2 elements that are allowed to slide or telescope back and forth to achieve a specific antenna length.\u00a0 In other cases the element(s) may need to be physically cut or altered to a specific length.\u00a0\u00a0 In the case of a common omni-directional fiberglass antenna the metal element(s) are housed within a fiberglass insulative sheath, and must be removed from the sheath to gain access.\u00a0 Here the user must expose the metal conductive element(s) and cut them to the proper length.\u00a0 If the antenna has multiple elements , each element may require a different cut and re-assembly must place them in proper order.<\/p>\n

To physically cut the element(s) a good metal file, Dremel tool, or fine tooth metal saw may be used to cut the element(s), or score and snap them carefully.\u00a0 Once done the element(s) go back into the fiberglass sheath in correct order.\u00a0 You can smooth any sharp points first if you like.<\/p>\n

\u00a0If an antenna is meant to be tunable it will come with a chart or other instructions as to what length is intended for a specific frequency, and perhaps instructions on how to physically perform the cut or adjustment.\u00a0 If\u00a0 you intend to cut-to-tune your antenna remember these\u00a05 key points:<\/p>\n