Description:
Integrated digital stereo signal generator, excellent audio, on-board RDS
The new STMAX 9000+ series FM exciters combine more features into a small board than ever before. With digital modulator, on-board stereo and RDS and all of this full controllable via LCD display with new 2-level MENU system and availability in 15W, 25W, 50W and 75W formats all powered from 12-15V this board represents realization of dreams for most prospective radio station builders.
The STMAX9075 comes in a 2HE enclosure with built-in XLR Board and LCD Display with Rotary Button. Frequency range: 76-108 Mhz
Technical specifications:
– RF Output Power: 0 to 15 Watts, 0-25W, 0-50W, 0-75W (fully variable via LCD in nice gradual steps), LCD power adjustment range can also be limited to 0-1W, 0-2W, 0-3W, 0-4W … 0-15W, 0-full, this is done with a jumper (exact options vary depending on model).
– Output connector: BNC female
– Output Impedance: 50 Ohms
– Frequency range: 87.5-108MHz
– PLL Steps: 50KHz-500KHz, adjustable
– Frequency stability: +/- 20Hz
– Spurious/Harmonic rejection: Harmonics: >50dB, Spurious: >-50dBc
– Power Supply 15W: 12-15V/2.5A
– Power Supply 25W model: 12-15V/4.5A
– Power Supply 50W model: 12-15V/7A
– Power Supply 75W model: 12-15V/12A
– Power connector 15W, 25W (barrel type, center +), 50W and 75W model: New design with plugin with 2 screw terminals
– Quartz Locked PLL Frequency Control, integrated digital modulator
– No Expensive Test Equipment Required
– Audio performance: Less than 0.1% distortion, 20Hz-15KHz
– RF output ruggedness: SWR protection, temp protection
– Polarity protection, temp protection
– Pre-emphasis, 50uS, 75uS or none selectable via LCD
– Stereo pilot level adjustable via LCD
– RDS pilot level adjustable via LCD
– MPX level adjustable via LCD
– Audio Input Impedance: 1Kohm, unbalanced
– Audio Input Level: -10dBu, +4dBu (selectable from LCD)
– Stereo separation: >50dB
– S/N ratio: >90 dB
– PC Board Size: 100x125mm
– Audio connectors: 2x RCA jack, 14-pin connector for external input board with balanced XLR inputs
– RF monitor: solder pads
What is the Audio Input Board for?
This add-on card adds two XLR balanced inputs and two RCA connectors plus USB audio input. It also comes with extra low pass filter, limiter and a jumper for optional external audio input (from mp3 player or something else). The inputs are ESD protect and have RF filters. This is of course an optional item but it is highly recommended and it does make life easier as you can install exciter far from the audio input connectors. It will improve sound as well, sometimes dramatically.
There is also AES/EBU version of this board!
What is modification with software for 76-108MHz?
This is the microcontroller IC with modified software that enables STMAX units to work from 76MHz to 108MHz. In order to use this you have to remove original IC from LCD control module (it is in a socket) and place this modified. Immediately frequency range will be expanded. You can change back to the standard IC at any time. This item can be purchased separately and it will also work with STMAX units that you purchased in the past (unless they are really old). Make sure to take correct version for your display! Important: The LCD shows less power than there actually is available below 76MHz. Also actual output power may be a bit less under 87MHz, how much depends on the board but usually about 20-30% less at 76MHz. Also the LCD itself will show less power than there actually is being transmitted. So keep in mind that your display will show maybe 5W but 10-12W will be transmitted.
