QAMP-40 • 16
check are the bias circuitry and RF path through the relay. The amplifier should
draw about ¼ amp with no signal applied. If you see more than that, recheck the
bias setting (see the section "INITIAL TESTS").
If you hear an AC hum on the transmitted signal, usual causes are RF getting
back into the power supply or a bad VSWR on the antenna.
These short checks in no way detail any and all problems that can rear their
ugly head, but should get you on the way to solving most errors. We'd like to be
able to foresee a problem a builder may encounter, but the sheer number of
parts and the permutations and combinations of installing them makes any list
of precise, exact solutions impossible. If you run into a roadblock, gather all your
thoughts and information and give a call to the factory for some help. If you elect
to enlist the help of a local expert, great...but be sure the expert is qualified (no
need for having someone lead you down the wrong path)! Remember: You may
always return the kit for factory service, and there's no charge if the problem is
our fault. See the warranty on the last page of this manual.
USING THE QRP POWER AMPLIFIER
Hooking up and using the amplifier is easy: Just connect your existing
transmitter to the QAMP input and the antenna to the QAMP output. A resonant
antenna is an absolute requirement for QRP operation, and an amplifier is not a
"band-aid" for a poor antenna system!
For maximum performance, a QRP station must include the following:
1
A resonant antenna (dipole or quarter-wave vertical);
2
Good quality coaxial feedline and connectors;
3
An effective earth ground.
We cannot expect good results from low levels of RF output if the power gets
wasted in lousy coax, corroded connections, or poor antennas.
If you elect to use an antenna tuner, it is extremely important that you
understand exactly how to use tuners and what they can and cannot do. A few
watts of RF can easily become lost in an incorrectly adjusted antenna matching
device. The whole idea of a QRP station is to keep things simple and
economical, so we cannot overemphasize the priority of a clean, efficient
connection of the amplifier output to a resonant antenna.
ENCLOSURE RECOMMENDATIONS
Your finished amplifier can be installed in a variety of enclosures of your own
design and choosing. You might be planning to combine several Ramsey circuit
kit boards in a single enclosure. Use of the inexpensive and attractive Ramsey
Summary of Contents for QAMP40
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