Vectronics VEC-1402DK - Manual (Page 15)

VEC-1402DK Instruction Manual High Performance 2 Meter Pre-Amp Kit
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isopropyl alcohol (or 95% grain alcohol) and an old toothbrush. Apply a
generous amount of alcohol with the toothbrush and scrub gently. Once the flux
has fully dissolved, blot the bottom of the board dry with an untreated tissue.
Give the preamp a final alcohol wash, and allow to dry thoroughly.
Caution: alcohol is highly flammable and must be used
with adequate ventilation! Use safety
goggles and avoid prolonged skin contact.
It's best to do this work outdoors!
Several light coats of clear plastic spray applied to the foil side of pc boards
protects against condensation-induced electrolysis damage. Do not allow over
spray to enter the coil assemblies.
Now that assembly and inspection is completed, you're ready to begin the testing
and alignment phase of construction.
TESTING AND ALIGNMENT
The best way to align a preamp is with a calibrated signal generator. However,
it's also possible to align the VEC-1402DK using off-air signals. Alignment is
easiest using a receiver with a built-in signal-strength meter (an analog meter is
generally better than a digital one for observing small changes in signal
strength). If your receiver lacks a tuning meter, listen to signals in the speaker or
view the audio waveform using an oscilloscope. The preamp must be powered
from a 9 to 15 volt DC source during alignment.
Generator Method:
Begin by connecting the preamp output to a FM receiver equipped with a
bargraph or analog type S-meter. Connect the preamp input to the RF output of
the signal generator.
Set the generator as follows:
•
Frequency .............. Desired frequency in the 2-meter Amateur band
•
Output Level .......... Start at -90 to -100 dBm (weak signal)
•
Modulation ............ FM, 1 KHz tone at 3-5 KHz deviation
Power up the preamp, and adjust as follows:
! 1. Tune in the generator signal and adjust the generator output level for a ½
scale reading on the receiver S-meter.