Vectronics VEC-1402K - Manual (Page 15)

VEC-1402K Instruction Manual 2 Meter Pre-Amp Kit
13
Off-air Method:
Set your preamp and receiver up, as described above, using an antenna in place
of the signal generator.
! 1. Tune in a steady-but-weak signal. Distant repeaters are especially good
because they transmit from a fixed location and remain "keyed up" during
both sides of the conversation. If you have no S-meter, the signal must
have audible background hiss for you to tell when it is getting stronger or
weaker. Stronger signals have less background noise (or better
"quieting"). Make sure the signal isn't fluctuating due to atmospheric
conditions or passing aircraft.
! 2. Carefully adjust coil L1 for maximum signal strength.
! 3. To achieve broad-band scanner coverage, peak the preamp at the center
of the range of frequencies to be covered. For example, if you monitor
activity between 146 and 162 MHz, peaking the preamp at 154 MHz will
give optimum performance.
This completes alignment of your preamp.
OPERATING INSTRUCTIONS
You may use the VEC-1402K with VHF receivers, scanners, or ham-radio
transceivers operating in the 140 to 162 MHz range. It may be mounted
internally in most receivers. Short runs of RG-174 cable should be used for the
RF connections. The preamp requires a 9-15 volt DC power source. This
voltage is easily “borrowed” from your receiver.
Warning: The preamp must never be installed in-line
with a transmitter or it will be severely
damaged! When used in a transceiver, the
VEC-1402K must be installed between the
antenna switch (pin-diode or mechanical
relay) and the radio's receiver circuitry.
When peaked for 146 MHz, the preamp delivers optimum performance across
the entire amateur band. In receive-only applications, you can remotely locate
the 1402K at your antenna site using a simple “bias tee”. The "bias-T” will
provide DC power over the coax line to run the preamp without attenuating VHF