557
These oscillators allow you to practice sending code at home, at work, in the field, or practically anywhere because they're easy to take wherever you may go. The internal speaker volume adjusts from barely perceptible to full-blast sound. A tone control gives you wide adjustment from treble to low-frequency tones. You even get a headphone jack for totally private practice. If needed, you can plug in an external speaker for loud classroom audio.
MFJ-557s run on a single 9-volt battery (not included) or optional AC power. They also have adjustable coding contacts for custom comfort. When you're done building skills with the MFJ-557, plug the key directly into your transmitter or transceiver and go on-the-air!
Learning Morse code with a practice code oscillator is easy! Get one of your MFJ-557 Deluxe Morse Code Practice Oscillators from DX Engineering and start enjoying Amateur Radio CW communication.
