Ramsey Electronics Adjusting Your FM10A Transmitter, Transmitting Frequency, Audio Connection

ADJUSTING YOUR FM10A TRANSMITTER

Keep all tests very brief until you have carefully chosen an open operating frequency in the FM broadcast band.

1. Transmitting Frequency:

After finding a suitable "open" frequency in the 88-108 MHz FM band, adjust L1 with the plastic alignment screwdriver until you hear the carrier frequency on a nearby FM radio. No audio input is needed to make this first adjustment, you can simply listen for a "quieting" in the normal background noise "hiss."

2. Audio Connection:

Adjust both Left and Right level potentiometers (R1, R4) to full counter- clockwise rotation. This is the minimum level position. Then increase them slightly. The best audio input for both testing and general operation are the stereo "line-level outputs" of a cassette deck or CD player. Most stereo systems have a variety of auxiliary output jacks of which one or more are line-level outputs.

Hooking up an audio source to your FM10A is really quite simple. However, there are some general rules:

•A terribly distorted sound is a sign of too much audio level. Simply rotate the level potentiometers, R1 and R4, CCW to reduce the level. Make sure you rotate each one about the same amount to maintain proper stereo balance.

•Stereo LP turntables are low-level output and will require the use of a preamplifier for proper audio input to the FM10A.

•NEVER connect the FM10A audio inputs to speaker outputs of a high power stereo system; such a connection will destroy the IC chip.

•Consider using a mike mixer for professional "radio station" sound. It will allow you to easily fade, mix and switch between various audio sources.

3.Stereo balance:

Adjust R7 for correct stereo balance. The better your ear for music and your understanding of quality audio devices and interconnections, the better will be the performance of your FM10A.