Vertical polarization with 50 Ohms impedance. Heavy Duty Fiberglass, 1 3/16" to 2 7/16" diameter. The Tram 1490 VHF Antenna is made of durable fiberglass construction. DC ground construction allows static dissipation for low noise ratio and maximum lightning protection.
The Tram antennas are tuned by cutting the interior sections. The cutting instructions are very exacting by millimeters. Remove the set screw at the bottom by the SO239. Slide all the guts out the bottom. Separate the sections, then cut each section.You can always leave it a little long and re-tune after checking the antenna after a primary tune. The item "Vertical Fiberglass Antenna VHF 144-174 MHz 6.7 dBd for Base Radio Tram 1490" is in sale since Monday, October 3, 2016. This item is in the category "Consumer Electronics\Radio Communication\Antennas\Ham, Amateur Radio Antennas". The seller is "radioresearchinc" and is located in Staten Island, New York. This item can be shipped to United States, Canada, Mexico.