Using the QRP Power Amplifier

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.

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:

1A resonant antenna (dipole or quarter-wave vertical);

2Good quality coaxial feedline and connectors;

3An 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

QAMP-40 • 16

QAMP40 specifications

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