Vectronics VEC-1290K - Manual (Page 19)

VEG1290K Instruction Manual AM Radio Transmitter
The VEC-1290K should be mounted in an enclosure. Vectronics has design a
matching enclosure for the VEC-1290K. The matching enclosure is anal metal
box which includes knobs, hardware, decals, and rubber feet. (Model VEC-
1290KC.) If you wish to supply your own, RadioShack offers several styles that
are suitable for this purpose.
Power requirements: The VEC-1290K operates from an external 12-volt D
source and draws about 100 mA. Wall-plug power supplies are an ideal sour of
power, but should have the following specifications:
1. Internally filtered and regulated 12-volt DC
2. Rated for at least 300 mA continuous
3. Be equipped with a 2.1 mm coaxial power jack, center pin
The VEC-1290K can be operated at lower supply voltages down to about 9
volts, but the transmitter range will be reduced. The transmitter is powered
when the SW1 push shaft is in the depressed position.
Once set to frequency, and the antenna tuned, the only control that needs be
set is the audio level (trimmer potentiometer R1).
Your home studio: The VEC-1290K will accommodate various sources of
audio-CD players, tape or cassette decks, or even a local microphone for the
budding DJ or talk show host. Unless a single audio source is going to be used,
the audio gain control R1 will have to be continuously adjusted for each new
audio source. Tape decks and cassette players provide "line level" audio outputs
for interconnections between decks and amplifiers. Microphone produce much,
much lower signal levels. As mentioned in the alignment section, capacitor C2
should be removed when using speaker level audio feeds.
Using a "mixer": To give your home station that "pro" sound, an inexpensive
four or five channel mixer may be used between the various audio sources and
the transmitter audio input. The mixer will allow the level for each source to be
set individually so all of your audio feeds will be balanced when played on the
air. The mixer master output can be used to set the modulation limits. The level
controls can be used to "fade" into one source from another, just like disc
jockies do on the air! You can also use an inexpensive graphic equalizer to tailor
your station's on-the-air sound-but the VEC-1290K as-is rivals the fidelity of
many FM broadcast stations!
Other uses: Let your imagination be your guide! We know of one VEC-1290K
that is being used on a DSS satellite system to play the MusicChoic6m Big
Band music channel to vintage AM radios throughout the housel