The AX-31C antenna is a compact VHF/UHF log-periodic directional antenna, a successor to the popular AX-31B antenna, with improved performance and reduced weight and dimensions, as well as additional packaging options: an outdoor mounting version and a hand-held one.This antenna is constructed on a high-quality fibre-glass substrate, with an integrated low noise amplifier. The user can also specify antenna versions without the inbuilt amplifier, which does not require any power to operate. Versions without the amplifier can be also used as low power transmit antennas.The AX-31C antenna covers a frequency range of 290 to 2200 MHz (a wider frequency range can be still received with reduced gain) and is ideally suited for reception of point-to-point communications where its directional characteristics can significantly improve rejection of interfering signals. The directionality is especially significant above 400 MHz; under 400 MHz the directionality gradually declines to the point when the antenna acts as a non-directional dipole.While designed to be entirely general-purpose and performing well with any third-party equipment, the WiNRADiO AX-31C antenna is especially suitable for WiNRADiO G3 Series of VHF/UHF receivers, in both professional and consumer applications. AX-31C Antenna with supplied cable.The antenna comes in three versions. The standard AX-31C version consists of a bare board suited for indoor applications, with an SMA connector and a battery holder for a standard PP3 type 9V battery (the battery and cable are not included). There is also an On/Off switch and an indicator LED on the board.With a simple modification which can be performed by the user, the antenna can be also powered externally via the coaxial cable, using a "Bias-T" power injector, such the WiNRADiO WR-BT-3500. A factory-configured antenna for 12V DC external power (without the battery holder) is available under model number AX-31CP.The user can also specify an antenna model without the internal amplifier (AX-31CX), which does not require any power to operate.The AX-31CH version comes encapsulated in a ruggedized enclosure with a hand grip, making it possible for the antenna to be used as a hand-held directional antenna for surveillance, monitoring and measurement applications.The antenna comes with a 3 meter (9.8 ft) cable with an SMA connector at the receiver end. There is no provision for a battery inside the unit; it is expected that the user provides 12V DC via the coaxial cable, using a "Bias-T" power injector, such as for example the WiNRADiO WR-BT-3500. The user can also specify an antenna model without the internal amplifier (AX-31CHX), which does not require any power to operate.The AX-31CM version of the antenna is suited for mast-mounting, including outdoor applications. The adjustable metal bracket makes it possible to mount the antenna on a mast of maximum 3" (approx. 75 mm) of diameter. This makes it possible to use this antenna for UHF point-to-point communications.The antenna comes with a 3 meter (9.8 ft) cable with an SMA connector at the receiver end. There is no provision for a battery inside the unit; it is expected that the user provides 12V DC via the coaxial cable, using a "Bias-T" power injector, such as for example the WiNRADiO WR-BT-3500. The user can also specify an antenna model without the internal amplifier (AX-31CMX), which does not require any power to operate. Such antenna can be also used for low-power transmit applications.