4 Way Stacked Dipole High Gain FM Broadcasting Antenna


4 Way Stacked Dipole FM Transmitter Antenna

Technical Specification

Click here for user manual
Gain 7.8dBi
Frequency 87-109 MHz
Bandwidth 87.5 to 108 MHz for SWR of 1.5
SWR 1.5 Max
Max Power 800 Watts
Construction Aluminium, Teflon and Ferrite
Connector UHF/SO-239 or N-Type (optional)
Input Z 50 ohm unbalanced
Polarisation Vertical
Weight 6Kg

No Retune, Continuous 87.5 - 108 MHz

The 4 way stacked dipole is basically a double 2 way stacked dipole. Just as with the 2 way stacked dipole this antenna covers the entire band from 88 to 108 MHz without a retune. You can use any FM transmitter at any frequency with this antenna. You could even use, with the correct combining equipment, multiple FM transmitters with different frequencies simultaneously with this antenna.

Long Life and High Reliability

This antenna was designed by us in 2006, so it's been around for a least 11 years. So far so good, no returns or complaints from any customers. Here's a photograph of this antenna installed by one of our customers in Ghana in 2012. It does what it says, full band 88 to 108 MHz, SWR of less than 1.5 and a gain of +7.8dBi. We supply this antenna as standard with our 400W and 800W ERP systems.

Resin Filled Insulator

The main feed point of each of the four dipoles contains a matching coil to reduce the antennas natural impedance of 72 ohms to 50 ohms. To protect this and the LMR400 coaxial feed from water and other weather related elements, the whole feed point is filled with resin.


2 Way Stacked Dipole FM Transmitter Antenna

50Ω Unbalanced Input

Each dipole has a unbalanced input of 50Ω which means the final input via the four way splitting is 50Ω. Due to this there are no RF currents running down th outside of the feeder cable potentially causing problems to the other users. This combined with the 7.8dBi high gain results in very low filed strength directly below the antenna which in turn minimises local interference to TVs and other equipment in the immediate vicinity.

The Best On The Market

You will not find a 4 way stacked dipole, with full 88 to 108 MHz broadband coverage without a retune and 7.8dBi gain on the market at this price. We are the most competitive, but without comprising the quality.

Mounting

Normally the dipole system clamps as high off the ground as possible to a mounting pole of at least 4 meters in length and between 25 and 38mm in diameter which you need to provide and engineer yourself.