Check the listing for details. THEMATCHBOX Multi-Tap Transmission-Line Transformer. Condition: New. Listed at 495.00 USD. THEMATCHBOX is a broadband multi-tap transmission-line transformer that raises the magnitude of the characteristically low impedances of electrically short-end fed antennas to an impedance suitable for direct connection to 50-ohm coaxial cable without significant loss or standing wave ratio. Superior to conventional transformers which perform well only above 1 MHz, THEMATCHBOX works well at low frequencies (down to 100 kHz) due to its manganese zinc alloy composition. The feed-point impedance of electrically short-end fed antennas is heavily influenced by local ground conductivity as well as the quality of the antenna’s ground system, in addition to its physical length. Multiple impedance step-up ratios are required to cover a wide range of soil conductivity and ground-system variations encountered in the field. THEMATCHBOX can be field configured for 8 different impedance transformation ratios, matching antennas with feed-point impedances of between 3 and 37 ohms to a 50-ohm coaxial feed line. THEMATCHBOX is designed for outdoor installation and is housed in a heavy-duty, weatherproof aluminum enclosure for mounting at the antenna feed point. Top and bottom flanges on the enclosure allow for simple installation on a variety of support types. Specs:Power Rating: 300 Watts ContinuousFrequency Range: 100 kHz to 1.7 MHzConstruction: Multi-Filar on Medium Permeability MnZn Toroid CoreImpedance Selection: Internal Jumper/Screw TerminalsAccessories: Mounting Straps; Ground Jumper/ClampConnectors: Coax: SO239; Ground: Internal StudDimensions: Height 6.25”; Width 4.0”; Depth 3.25”Height including Flanges: 7.5”Cover Attachment: 4 ScrewsWeight: 2.5 lbsNEMA Rating: 1, 2, 4, 4X, 6, 12 and 13IP Rating: IP68