FM power dividers allow more than 1 antenna to be added to your antenna system to increase gain, range and sometimes to obtain desired radiation pattern. Every time you double number of antennas you get 3dB of gain (ok, there are also some minimal losses to consider). You need 6dB or a bit more of gain to double your range. This means upgrading your single dipole to 4-dipole antennas doubles your range and increases your effective radiated power to 4x of the initial value.
– 1kw transmitter + 1xdipole antenna: ERP=1KW, antenna gain = 0dBd
– 1kw transmitter + 2xdipole antenna: ERP=2KW, antenna gain = 3dBd
– 1kw transmitter + 4xdipole antenna: ERP=4KW, antenna gain = 6dBd
(This is assuming no losses in coaxial cable and combiners)
Several combiners are listed and described below, select the one that fits your requirements and budget best.
Coaxial splitter (2-way or 4-way), first two options down on the list
Low cost solution that gets the job done just fine. Coaxial cable to the antennas
does not have any connectors installed yet, you will have to do that. 3 cm of cable can be stripped to install a connector on each of the splitter cables. Cutting off any piece of coax would change
the frequency band of the splitter so be carefull.
– MAX Power handling: 750 Watts
– Inputs to antenna: No connector, you can strip 3cm on cable ends to install a connector
– VSWR: better than 1:1.5 (88-108MHz)
– Freq. range: 88-108 MHz(no tune)
– Output to transmitter: 750W
– Weight: 3Kg
Specifications for remaining splitters:
Simple to install, these power dividers are ideal for feeding an array of antennas to allow you to increase your signal coverage area, they are equipped with connectors. You will need inter-bay cables to connect the splitter to the individual dipoles. These cables should be 50 ohms and all of exactly the same length.
– Input connectors: N female, 7/16 or IEC (read product name, for example 2KW 4-way power divider (4xN female+7/16) means 4xN connectors going to antennas/dipoles)
– Output connectors: N female, 7/16 or IEC (read product name, for example 2KW 4-way power divider means 7/16 output connector going to transmitter)
– Maximum power handling: read product name, for example 2KW 4-way power divider (4xN female+7/16) means power handling is 2KW transmitter max
– Easy installation
1-step vs 2-step, which is better?:
Due to design constraints (and physical laws) it isn’t easy to construct a splitter with perfect impedance match across entire FM band. Hence best match is usually possible somewhere in the middle of the band around 99MHz and is somewhat worse at the band edges. This means a SWR of around 1:1 @99MHz and around 2:1 at band edges (87,5MHz and 108MHz) when using 1-step combiners. The advantage of 2-step combiners is that they perform better at band edges =that translates into a SWR of 1.5:1 at band edges. 2-step combiners are about 2x bigger, heavier and more expensive. So which is better for you? If you plan to transmit somewhere in the 95-104MHz segment you might be perfectly happy with 1-step combiner. However if you plan to operate close to 108MHz or 87.5 you should seriously consider 2-step combiners. One more thing, with low power FM transmitters up to about 100W I wouldn’t worry about 2-step splitters, 1-step is perfectly ok.
Important: Due to large size and irregular shape of these packages the website often gets shipping cost wrong. One long item is expensive to ship due to volumetric weight but if you purchase several they can be combined which makes extra items cheaper to ship. Also sometimes we have to use wooden case which adds about 100 euro to the cost of antenna. For exact shipping cost please contact our sales department, be sure to give them your exact address and they will quote you shipping. It also does not hurt to ask for a special discount.
Recommended accessories: We recommend AA-230 antenna analyzer for checking SWR of the antennas. Grounding kits should be considered as well, they ensure lightning protection. They should be installed at the antenna (if needed, most dipoles are grounded anyway), at the tower base and at the point of entrance into transmitter building. Also use self-sealing tape which turns into rubber and protects against moisture from entering your antenna system.
STOCK and LEAD TIMES: We do our best to list all possible configurations to meet any demand out there. However we don’t always stock every type. We usually stock 1-step 2-way dividers with all 7/16 connectors and 1-step 4-way dividers with all 7/16 connectors. The others we may stock or not depending on current situation. If you are in a hurry please ask.