|Frequency 87-109 MHz|
|Bandwidth 87.5 to 108 MHz for SWR of 1.5|
|SWR 1.5 Max|
|Max Power 400 Watts|
|Construction Aluminium, Teflon and Ferrite|
|Connector UHF/SO-239 or N-Type (optional)|
|Input Z 50 ohm unbalanced|
The double stacked dipole has the benefit of 4.8dBi of gain and broadband operation. This is achieved by slightly phase staggering the signal to each dipole. Providing the antenna is mounted correctly the SWR is less than 1.5 across the whole band from 87.5 to 108 MHz. This antenna system never needs tuning, just put your transmitter on any frequency from 87.5 to 108 MHz and switch on. If you require more than 4.8dBi of gain the 4 way 7.8dBi and the 8 way 10.8dBi stacked dipoles based on this model are also available
The RF field strength directly below this antenna is lower than that of a single dipole. The built in balun provides a truly unbalanced input and prevents any RF currents traveling down the outer of the feeder cable. This combined with the low field strength below the antenna reduces the chances of audio and TV interference considerably and maximises RF power to the horizon.
We designed this antenna back in 1996 and because it spanned the entire 88 - 108 band without a retune, we made it the standard antenna we sold with all our 200W, 250W and 500W ERP systems. Just like our other antennas, we can count the number of returns over 20 years on less toes than you have on one foot. It has been installed in just about every area of the world without suffering wind, corrosion or other weather problems. It will last upward of 15 years with little maintenance.
There are not many complete 2 way stacked dipoles on the market and certainly not at the price we sell this one for. Without a shadow of a doubt, this is the best value for money and performance high gain and full broadband FM 2 way stacked dipole you will find on the market.
As with all high gain antennas, with correct mounting the RF field strength directly below this antenna is much lower than a single dipole. The built in balun prevents any RF currents going down the outside of the cable and interfering with other cables on the tower or mast. This low field strength below the antenna lessens the possibility of audio, TV and other interference considerably to users closely local.
The main feed point of the dipole 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.
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.