AM transmitter with DSP processing, PWM modulator and DDS frequncy generator
While for many mentioning AM transmitters brings back childhood memories, these are actually still used widely in some countries. Besides, AM can be lots of fun to play with. Long wire antennas, different signal propagation (even worldwide), the nostalgia that comes packed with it... well, it is something very different in this modern age.
Our old AM MAX units sold out many years ago and for a long time we wanted to make a new AM transmitter, this time with different, more modern approach, with new better parts and better specs. And we finally did. It is equipped with DSP which makes it possible to control parameters of the audio chain, such as the compression, low pass audio filter cut frequency and preemphasis via convenient LCD with menu system. Other features, such as the fully solidstate PWM modulator which ensures crisp audio, 125% positive peak modulation, compact form factor, plenty of audio input options and LCD display unit make AMMAX8000+ really something special in this modern age.
What is new in AMMAX8000?
- New larger high power FET (300W)
- Robust PWM output stage based on larger FET, extra LC stage in PWM filter
- A number of small fixes and improvements to improve reliability
- Added anti-aliasing audio filter after DSP
- Larger heatsink
All our manuals are available here.
What is the audio input board:
- RF Output Power AM: ~10-25W carrier (24V-50V DC stabilised, use 50V for maximum power), varies with band and frequency
- Peak RF Output Power: ~100W (due to > 125% positivemodulation)
- Output connector: BNC
- Output Impedance: 50 Ohms
- Frequency Range (MW version): 540-1710KHz
- Frequency Range (shortwave version): 160m, 80m, 40m (other SW bands also available, please ask)
- PLL Steps: 1KHz
- Frequency stability: +/- 50Hz
- RF output: Harmonics: -30dBc typ (varies with frequency, if necessary use external filter or high-q resonant antenna)
- RF output (purious): -70dBc
- Power Supply: 48V/2.5A DC stabilised
- Wideband design, no tuning required
- Audio performance: compressor, low pass filter, limiter, treble, bass adjustment
- RF output ruggedness: > 2:1 VSWR
- Modulation: AM (CW input on-board. TTL 5V for disable)
- PCB size: 100x125mm
- Audio input: accepts either mono or stereo signal (transmission is mono)
- Audio connectors: 3-pins for GND, L and R signals. With audio input board you also gain XLR, RCA and USB audio input
- DRM support: On-board jumper can disable DSP processing which is great for DRM modulation
- Modulation: AM, >125% positive mod
- PWM circuit is opto isolated and can be used to drive high power external stage
- Audio input board adds XLR, RCA and USB audio inputs to the transmitter. It is also equipped with extra input limiter, low pass filter and balanced input stage with ESD protection. You may think this is not needed, but believe us it is nice to have.
Suitable DIY antennas for the AM transmitters:
Link 1, link 2, link 3, link 4, link 5
What is the Barix audio streaming with MP3 playback option?:
- We will install Barix instreamer inside with STL firmware for you and you can play audio from IP audio streams. There is also automatic MP3 playback from USB that starts where there is no active stream.
Discuss AM transmitters in our forum!