DSP digital signal synthesis, excellent audio, on-board stereo and RDS
The design of the STMAX 3000+ micro series is based on STMAX3015+ and also looks quite similar at first glance (while being smaller), however it comes with a different DSP modulator and DIP switches. The result is a rugged and solid FM exciter with completely flat power output across the entire FM band at 15W or 25W, designed to run silently 24/7. Your dream FM exciter is a reality right now!
Manual will soon be available here under Additional information tab.
How is STMAX3000 micro different from the STMAX3000?
– Smaller form factor
– DIP switch mode supported, works also without LCD
– Can be controlled entirely via RS232 (no LCD unit required for this) terminal or your control unit, see photos below.
– Available in 15W and 25W flavor
– 0.5W power limit jumper (in addition to 1W, 2W, 4W and 8W)
– New better modern output transistor
– MCX antenna output connector (N, SO239-CB and BNC pigtails are available, they plug into MCX)
– Firmware of RF board is now upgradeable (requires USB to serial converter – our RS323 IO board)
– Compatible with STMAX3015 board (it is smaller but you can use old display and audio input boards with these and it will work)
– RF Output Power: 0 to 15 Watts, 0-25W (fully variable via LCD in nice gradual steps), LCD power adjustment range can also be limited to 0-500mW, 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 antenna connector: Soldering directly or MCX socket (get pigtail to obtain N female or BNC female)
– Output Impedance: 50 Ohms
– Frequency range: 87.5-108MHz (expandable to 76-108MHz with microcontroller)
– PLL Steps: 50KHz
– Frequency stability: +/- 50Hz
– Spurious/Harmonic rejection: Harmonics: >50dB, Spurious: >-50dBc
– Power Supply 15W: 12-15V/2.5A
– Power Supply 25W model: 12-15V/4A
– Power connector. 3-wire connector (middle is +), the cable is included
– Quartz Locked PLL Frequency Control, DSP digital modulator
– No Expensive Test Equipment Required
– Audio performance: Less than 0.1% distortion, 20Hz-15KHz
– RF output ruggedness: SWR protection, temp protection
– Pre-emphasis, 50uS, 75uS selectable via LCD
– Audio Input Impedance: ~ 1Kohm, unbalanced
– Audio Input Level: -10dBu, +4dBu (selectable from LCD)
– PC Board Size: 100x125mm
– Audio connectors: 2x RCA jack (optional), 14-pin connector for external input board with balanced XLR inputs
– RF monitor: solder pads
What is the Predrilled LCD front panel?
This is a rectangular piece of aluminum with predrilled holes for LCD display, 3 buttons and LED diodes. It also has 4 holes in the corner so you can easily mount this to your case. This makes it much easier to mount the transmitter into a nice looking case (eliminates the hard work with the LCD). This is of course an optional item.
Controlling STMAX3015 micro RF board via RS232 terminal (LCD not required)
The RF board board can be controlled with your own LCD display or computer via RS232. All you need is a terminal, the command syntax is very simple. For this to work you do not need any LCD display unit as RS232 port is on RF board itself. The protocol is very simple, this photo explains it all. The pinout of the RS232 header is explained on the board itself.
Advanced graphics display with VU meter and web control interface
This is our new advanced high performance graphics OLED display with many incredible new features that older units did not support. First of all, it offers a large graphics OLED display, it connects to internet via Ethernet and than lets you control the unit via web browser (no windows software needed anymore), it lets you update firmware of the display and attached modules which before was not possible, each display comes with two-color bright VU meter, rotary button, and aluminum front panel with plexiglass. Advanced menu system lets you set everything either from the display itself or the web interface. This is of course an optional item. For extensive manual look down under Additional Information tab. Any questions send us an email.
What is the RS232/USB IO board and why do I need it? NOT NEEDED WITH OLED DISPLAY!
IO board is required, if you want to control STMAX3000+ remotely via PC. It plugs into the LCD control module and gives you USB port making it possible to connect STMAX card to PC computer and control it remotely. IO board is also needed to upgrade firmware of STMAX3015 micro RF board.
OLED graphics display has its own IO board and does not require IO board! This advanced display
What is the Ethernet remote control module for? NOT NEEDED WITH OLED DISPLAY!
This add-on card lets you connect this transmitter to the PC via Ethernet network. You can control and monitor the status of your transmitter over Ethernet or Internet. This is of course an optional item. This card requires RS232/USB IO as it plugs into it.
Graphics LCD display has its own USB and Ethernet IO board and does not require extra IO board or ethernet module.
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 the STMAX3015+ micro 15W MEGA BUNDLE?
To make the most of your STMAX3015+ micro board take advantage of this super mega deal. This is a cost effective way to build a fully featured 15W transmitter with all the bells and whistles. Here’s what this mega bundle contains:
– STMAX3015+ micro 15W (Stereo + RDS) board
– Advanced graphics display with VU meter and web control interface (includes LCD panel with plexi window)
– Audio input board AES/EBU (RCA+XLR+USB) + 20cm flat cable
– Pigtail N female to MCX (antenna connector)
– 2x RCA audio input connectors
– 14-pin LCD display flat cable (45cm, 2 connectors)
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. To optimize for more output at 76-90MHz you can ask for tips on changing several components (it is easy).
What are the pigtail cables and RCA connectors?
Pigtail cables will make your build look neat and professional and you will want to use these as they are worth every penny. Makes your life easier as you can easily route your antenna connector where you want it.
RCA connectors are normally not included and installed as most people use audio input board. They might interfere with your box design as well. But you can buy them and install them yourself. We will just put them in the shipment with the exciter and you can even decide later not to install them, it is up to you. It is very easy to solder these in.
To look for a suitable antenna check: here.
To look for a suitable coaxial cable check: here.
Some enclosure ideas are here.