|Click here for user manual|
|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|
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.
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.
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.
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.
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.
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.