FASM1S is a professional FM PLL radio broadcast transmitter. It has excellent audio quality, adjustable RF out power (up to 300W or 500W depending on model), easy menu using only four keys, 4x20 LCD (white characters on blue backlight) which displays frequency, FWD, REF readings, and modulation level, and many other features.  Internal microcontroller circuit checks the whole unit and provides various protections, among which VSWR protection, temperature protection, etc. 

It has two audio inputs for the left and right channels, which can be set as balanced or unbalanced by the user. Both inputs are pre-emphasized for either 50usec or 75usec (user-selectable) for mono modulation. A third auxilliary input is available for connection of stereo multiplexed signals. Thru it, it can be modulated with a stereo generator signal for excellent quality stereo broadcasts.

You can either connect left and right audio at the rear balanced XLR inputs, or feed it from an external stereo encoder through the MPX unbalanced (BNC) input. It can also accept RDS signal from an external source at the corresponding dedicated BNC input. It also provides left and right unbalanced inputs at the front panel which work in parallel with the corresponing inputs in the rear.

Note the transmitter comes with its own built-in stereo generator as standard.  This, however, will be automatically bypassed if you select so from the menu to work with your preferred external stereo encoder if you so choose.

The transmitter is based on a FULL BROADBAND DESIGN with no variable caps or other adjustments! Everything is done via the menu.  Its frequency can be set anywhere from 87.5MHz to 108MHz (special model for 76-90MHz Japanese band also available) and minimum step of 10KHz.  We offer FASM1S with two different final RF amplifier models, one that can go up to 300W (FASM1S-250) and another for up to 500W (FASM1S-500).

You can manually turn the RF output on/off, or use the built-in real-time clock to set a daily or weekend schedule for automatic on/off at a specific time. With this option, one can leave the unit at a remote site and have it operate only for the specified hours. It is also possible instead of turning off to lower the RF output power at the preselected levels (for day/night regulations and/or economy reasons).  The transmitter has telemetry connection via a standard RS232 port, or optionally, via Ethernet.  From this you can remotely fully control and monitor the transmitter as if you were on-site.  For example, when the transmitter is working in a remote location.

 

All user settings including the power-on frequency can be saved to the built-in non-volatile memory.

The unit meets all FCC and CCIR requirements for FM transmitters but it has not been FCC certified. It has an excellent spectral purity with harmonics rejection better than -60dBc as can be seen on a Spectrum Analyser, spurious output better than -80dBc, and accuracy of the VCO lock-on frequency of +/- 200Hz. RF output is disabled when PLL is unlocked. You can also manually turn the RF output on/off.