Description:
5-element log-periodic antenna for low to medium power FM transmitters
Precise manufacturing, attractive price and no-tune operation make this directional log-periodic antenna (radiates most of the signal in one direction) a good match for LPFM to 100W max transmitters. It is recommended if you want to cover a specific direction, only 100W max power will be used and wide-band operation without tuning is a plus. Due to high gain it also greatly enhances signal reception, if used in a receiver so it is an excellent choice for measuring receivers. Several antennas can be combined to create very directional very high-gain antenna setup.
Technical specifications for version with F connector:
– No. of elements: 5
– Gain: 6,5 dBd
– Front/back ratio: 15 dB
– Beam width -3dB: H 140° / V 60°
– Vswr/ROE: 1:1.5 max (about 1:2.0 when used in 50 ohm systems)
– Power handling: 100W max (model with F connector)
– Wind resistance @120km/h (720N7m2): 27,5 (model with F connector)
– Impedance: 75 ohm (minimal SWR increase at 5o ohm, below 2:1)
– Antenna dimensions: 1720 mm x 1220 mm x 50mm
– Freq. range: 87.5-108 MHz (no tune)
– Connector: coaxial cable is wired directly to the balun (model with F connector)
– Weight: 1.3Kg (aluminum)
– Full mounting material is included!
– Radiator is DC grounded (great for lightning protection)
How much ERP will my transmitter have with one LOG5FM antenna in ideal situation?
100W transmitter: Your ERP will be increased 6dBd (4x), 100W transmitter will have 400W ERP*, this usually doubles your effective range. Max transmitter output power in this configuration is 100W.
(*) not taking coaxial cable losses into account so slightly less. ERP means the power equivalent required to produce identical signal with a dipole antenna which has a gain of 0dBd.
How much ERP will my transmitter have with two LOG5FM antennas in 2-bay configuration?
100W transmitter: Your ERP will be increased 9dBd (4×2=8), 100W transmitter will have 800W ERP*
9dBd gain usually results in more than doubled range, note the beam will narrow as well and directivity will increase. Max transmitter output power in this configuration is 200W, 100W per antenna (ERP will be 1600W).
(*) not taking coaxial cable losses into account so slightly less. ERP means the power equivalent required to produce identical signal with a dipole antenna which has a gain of 0dBd.
Antennas must be installed vertically, for distance between antennas it is same as for dipoles:
How much ERP will my transmitter have with four LOG5FM antennas in 4-bay configuration?
100W transmitter: Your ERP will be increased 12dBd (4×4=16), 100W transmitter will have 1600W ERP*. 12dBd gain usually results in quadrupled range, note the beam will narrow as well and directivity will increase. Max transmitter output power in this configuration is 400W, 100W per antenna (ERP will be 6400W).
(*) not taking coaxial cable losses into account so slightly less. ERP means the power equivalent required to produce identical signal with a dipole antenna which has a gain of 0dBd.
