FX 146
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MICROPHONE & SPEAKER INFORMATION
The FX transceivers with the hardware supplied are designed to accept
standard ICOM or ICOM-compatible speaker-mikes such as MFJ-284. The
most conveniently available such unit is Radio Shack No.19-310.
Be aware that the receiver audio amplifier is capable of supplying a husky 2
watts or more of audio power and will drive full-size communications
speakers to excellent volume levels.
The PTT switching circuit can be activated simply by introducing a
resistance (e.g. 10K) from the microphone input to ground. This resistance is
enough to trigger the PTT circuit without interfering with the microphone
audio input.
Consider these factors in selecting microphone, speaker and/or speaker-
mike for FM voice operation. If your microphone and speaker preferences
differ radically from the use of a speaker/mike, and you do not wish to alter
the front panel, remember that you also have very easy access to mike and
speaker lines via J1, the packet connector.
A FEW ANTENNA CONSIDERATIONS
The idea of building your own transceiver is to save money and enjoy your
hobby. Effective VHF and UHF antennas are easy and inexpensive to build,
whether for fixed or mobile use. There are plenty of off-the-shelf antennas to
buy, but don't hesitate to "roll your own."
If you are a newcomer to ham radio, you'll discover many strong opinions
about the "best" antenna to use. A home-built ground plane vertical or even
a dipole can provide very satisfying results. Whether you need a gain factor
or directivity in your antenna depends on your operating goals. Regardless
of the style of antenna, it really pays to give serious attention to electrically-
solid, weatherproof connections of the coaxial cable to the antenna
elements. A simple antenna in good condition will outperform a fancy one
that's been neglected.
Popular ham magazines and ARRL publications provide plenty of antenna
building ideas. MFJ Enterprises offers good value in simple ready-to-use
antennas for 2 Meters.
FX-146
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B. Unpack and study the design of the chip, noting both ends are metallic.
C. Lightly pre-tin both PC board points.
D. Holding C75 in place across the two tinned points with tweezers, gently
touch one junction with the soldering tip. The connection should solder
easily.
E. Solder the other end and touch up the first one if necessary.
Identify and install the following components:
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TX4: C56, 10 pf.
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TX5: R29, 100 ohms (brown-black-brown).
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TX6. L11, miniature .33 uh. inductor (small green body, two orange
stripes)
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TX7. C44, .001 uf.
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TX8: C76, 15 pf.
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TX9: C82, 10 pf.
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TX10: R36, 10K (brown-black-orange).
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TX11: R110, 10K (brown-black-
orange).
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TX12: R34, 270 ohms (red-violet-
brown).
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TX13: C97, .01 uf.
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TX14: Install Q10, NE021, the
Transmit Buffer transistor. It installs
in the same way as Q3, which was installed in step DR19. Go back and
re-read the steps required when installing a transistor of this style. You
must make sure it is seated snugly against the board before soldering.
At this point, all transceiving functions except final transmitter output power
may be tested and aligned. Q10 has plenty of RF output (10 milliwatts) for a
signal that can be heard in a nearby receiver or scanner. You may test and
align the transceiver now or do so after installing the remaining transmitter
parts.