On open rural land with good antenna height you can expect 50kW EIRP to reach 70 miles, maybe a little more. In a dense city like New York with tall buildings made of steel and concrete, this would cause great attenuation to the signal and reduce the coverage area by 10 times, you could expect only a few miles. So, the transmission distance really depends on many factors. If you send us the GPS coordinates of your antenna site and the antenna height, we can make a plot of you using satellite elevation data of where the signal can be received. We have a great example of this HERE
The raw power being generated by the transmitter and amplifiers is 4kW or 4000 watts. This is done by using four 1kW amplifiers as shown in the picture. The power from each amplifier is combined or summed together, in phase, to produce the 4kW of power. It's possible to switch off at any point and even remove a 1kW amplifier leaving three 1kW amplifiers and a total of 3kW of power still operating. This has great benefit for being able to service, clean etc. an amplifier without taking the station 'Off Air'. In such an event the radio station power going from 4kW to 3kW would only be a 25% reduction and not noticeable by most listeners.
This is where the magic happens, this huge eight way antenna transforms the transmitter power by 10 times to 50kW and this is even after taking the cable losses into account. This transformed signal is effective radiation, what it means is that if you stand at the horizon many miles away, the signal voltage with this eight way antenna will be exactly the same and indistinguishable from the signal voltage of a 50kW transmitter using just one dipole antenna. The power is effectively identical, hence the name Effective Isotropic Radiated Power (EIRP).
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|
|4||1000W FM Power Amplifier|
|4||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.