Ramsey Electronics FR146 manual Testing, Alignment And Adjustment, Alignment Procedure

TESTING, ALIGNMENT AND ADJUSTMENT

To prepare the FR146 FM VHF Receiver for reliable monitoring operation, you will need these basic tools:

❒1. A useful VHF signal source.

❒2. Hexagonal, non-metallic coil slug alignment tool for L3.

❒3. Small screwdriver to adjust L4.

1.Signal source: This signal can be from your test bench equipment or from a "live" source such as a local repeater. The "live" signals are best for fine-tuning, but they also have that VHF communications character of being fast and to the point. Good test bench signal sources include your own 2-meter tranceiver, if you are licensed to use it, a signal generator or grid-dip oscillator. If you do not have a steady test signal source for the band within 135-175 MHz of primary interest to you, and still wish to verify immediately the proper operation of your FR146, a good and steady VHF signal source will be your local NOAA Weather Service station, broadcasting around 160 MHz. Once you have verified reliable reception of your regional NOAA station, adjustment to your desired listening range will become easier.

2.L3 Alignment Tool: If you do not already have a set of plastic or nylon coil alignment tools and do expect to try further Ham radio or electronic hobby projects, such tools are worth having and can be found inexpensively at any electronics store including Radio Shack. While a metal Hex key wrench can fit the coil slug, the metal itself would damage the coil inductance drastically and therefore should not be used. With patience and sandpaper, a useable tool might be formed from a wood or plastic rod.

ALIGNMENT PROCEDURE

❒1. Make sure the power switch is off.

❒2. Connect the antenna, earphone or speaker and battery.

❒3. Turn the slug of L3 until it is even with the top of the coil form.

❒4. Now, turn the slug of L3 clockwise 7 turns back into the form.

❒5. Turn the slug of L4 until it is flush with the top of the coil and then turn it 2 turns back into the coil.

❒6. Turn all three controls to the left, fully counterclockwise.

❒7. Turn the power ON.

❒8. Turn R2 (Volume control) until you hear some noise.

❒9. Adjust L4 for maximum noise from the speaker.

FR146 • 18