On open rural land with good antenna height you can expect 25kW EIRP to reach 70 miles and maybe a little more. 25kW EIRP is a formidable power and is suitable for regional broadcasting as opposed to local broadcasting. This power level is also useful in densely urbanised cities where there are tall buildings, a lot of steel and concrete. In extreme cases in some directions we have had customers report signals up to 130 miles wit this power level. Transmission distance is always the most difficult question we have to answer. For more accurate predictions we can make plots based on GPS coordinates, antenna height and radiated power like these HERE
To achieve 25kW EIRP only 2kW of transmitter power is needed if the correct antenna is used with high grade coaxial cable. The 2kW of power comes from two separate 1kW amplifiers that are driven by a distribution amplifier and Veronica® 1W PLL driver. Just the same as the 50kW and 100kW system, because this system uses more than a single amplifier. A complete shutdown or signal failure can only occur if both amplifiers go down at exactly the same time, this is nearly impossible with super high odds. So if you need system reliability and a station on air, always, with no breakdowns, two amplifiers like this configuration should be your minimum requirement.
In these systems the antenna is everything, you must treat the antenna like your best friend, even a brother (sister too! for the pc sensitive). The antenna just looks like lumps and rods of aluminum screwed together, and it is! but it is much more, the antennas length, shape, installation and height dictate if you signal is going to do tens of miles or less than one mile. The antenna is more important than the transmitter and amplifiers. This antenna system uses eight folded dipoles optimally spaced to produce 12dBi of gain. Cut short, this multiplies the signal pointing to the horizon by 12.5 times resulting in 25kW EIRP transmission signal.
The coaxial antenna cable used on this system is LMR600. This is super low loss with only -1dB of loss over 40 mt (at 100 MHz). This is the reason that most of the power developed by the amplifiers is transferred with ease to the huge gain antenna stack. The cable is robust but at the same time flexible with an external diameter of about 13mm / 0.5 inch. Both ends of the cable are fitted with high powered Teflon DIN7-16 connectors.
|1||FM Stereo Driver with Audio Processing|
|1||4 Way Distribution Splitter Amplifier|
|2||1000W FM Power Amplifier|
|2||LMR600 40m /131ft Cables|
|1||All Other Connecting Cables|
|8||Broadband High Power Folded Dipole Antenna with Tower Mounting Clamps|
The FM signal starts in the internal Veronica PLL which produces the super low noise and highly stable FM signal. You can find more info on this at in our 1W Exciter (PLL version 10). Then the internal stereo coder and audio processor boards provide a loud and crisp audio signal on the listeners radio. If your more of an expert, you can if you want use an external processor such as Orban, Inovonics or PC generated MPX/RDS, the limiter and stereo coder we supply can be completely disabled.
We hereby declare that this equipment complies with;
• ETS 300384 European Telecommunications Harmonised Standard when used with an audio compressor limiter supplied and tested by Aareff
• EN 301489-11 V1.3.1 (2006-05) EMC Electromagnetic Compatibility when used with 1 meter AC mains cord supplied. If the installation engineer needs to extend this cord, this and the audio input cable should be no more than 3 meters in length to remain in compliance with EMC directive.
• 2006/95/EC Directive (2006-12) LVD Low Voltage Directive.
Equipment compliance is possible using equipment from and in conjunction from other manufacturers, but since this is beyond the control of Aareff Systems, Aareff Systems cannot or be expected to guarantee compliance in this situation.
The following list are the FCC technical requirements for FM broadcasting. We confirm and verify that this transmitter complies with the technical requirements.
47 CFR Chapter I Federal Communications Commission sections:
• 73.1560, 2.1046 RF Power
• 73.1545, 2.1055 Frequency Stability
• 73.317, 2.1049 (e)(3) Emission Limitation, Emission Mask
• 73.317, 2.1057, 2.1051 Emission Limits, Spurious Emissions at Antenna Terminal
• 73.317, 2.1057, 2.1053 Emission Limits, Field Strength of Spurious Emissions
This graph is based on average maximum customer reports in some directions. Basically this shows the maximum ranges really ever recorded. Most of the reports were radio station listeners that phoned, texted, Whatsapp etc into the radio station programs operated by our customers.