Please remember, though, that a flashlight bulb does NOT present the proper load impedance to the transmitter output, so theoretical calculations based on the bulb`s rating can only be approximate. For example, the PR-4 at full brilliance presents only an 8.2 ohm load to the transmitter.

If ANY flashlight bulb lights up when connected to the antenna jack of this transmitter, you can be satisfied that you have RF output power ROUGHLY comparable to the DC power rating of the bulb you are using. If you burn out your bulb, rejoice and put your rig on the air!

Amateur radio magazines and handbooks provide a variety of circuits for RF wattmeters and relative field-strength indicators, including methods of using your VOM as an indicating device. CQ magazine for March 1990 offers an article by KB4ZGC on how to make a highly accurate yet inexpensive a dummy load and wattmeter capable of showing 1/10-watt differences in RF power.

MAXIMIZING RF POWER OUTPUT:

Hopefully, the introductory discussion about the amount of power increase needed for significant boosts in RST reports will satisfy most users that good communication opportunities are afforded by the transmitter's QRP output. The simplest way to ensure maximum reasonable power output without component damage is to run the DC voltage in the 14 to 15 volt range, observing a maximum limit of +18VDC.

IMPORTANT NOTE: If you are experimenting with this transmitter and see a sudden and massive increase in power output and DC current, you have not reached the promised land or created a 25 watt transmitter! Sudden surges like that are a sure sign of amplifier self-oscillation. Kill the DC power supply immediately, because your Q3 RF power transistor has headed to self- destruction while probably interfering with every TV set in the neighborhood. A poorly matched antenna along with higher supply voltages is usually responsible for this occuring. Any prolonged "parasitic" emissions will also overheat and destroy the components in the Q4 keying circuit.

Please remember that modified PC boards are not eligible for factory repair service. We encourage experiments and improvements of basic Ramsey kits, but we ask that you first get the kit working as designed and understand it - before making ANY changes. We regretfully cannot offer any other guidance in modifying our kits. You're on your own, that's what experimenting is all about!

TRANS-RECEIVE OPERATION:

If you plan to use this transmitter with a Ramsey HR-series direct conversion receiver for portable operation, it will be necessary to work out a receiver muting and keying sidetone circuit. A matching companion to your transmitter

QRP-20 • 19

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Ramsey Electronics QRP20 manual Maximizing RF Power Output, TRANS-RECEIVE Operation
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QRP20 specifications

The Ramsey Electronics QRP20 is a compact and innovative low-power transceiver designed for amateur radio enthusiasts who appreciate both portability and efficiency in their operations. This QRP (low power) radio is primarily aimed at those who seek to operate on the HF bands, providing an exhilarating experience for operators who thrive on the challenges and satisfaction of making contacts with minimal power output.

One of the standout features of the QRP20 is its compact design. This radio can easily fit into a backpack, making it ideal for field operation, portable use, or emergency communication scenarios. Weighing in at just a few pounds, it’s lightweight enough for extended outings without burdening the operator.

The QRP20 operates on a range of HF bands, specifically covering 20 meters, which is especially popular among amateur radio operators for its relatively consistent propagation and activity level. The transceiver leverages solid-state technology, ensuring reliability and optimizing performance. It can produce an output of up to 5 watts, which is standard for QRP operations, allowing operators to experiment with different antenna configurations and propagation techniques.

Another significant aspect of the QRP20 is its user-friendly interface. The radio features a straightforward layout with well-placed knobs and buttons for efficient tuning and operation. The built-in digital display provides clear visibility of frequency information and operational status, enhancing the overall user experience. In addition, the QRP20 includes a narrow bandwidth filter, which effectively reduces noise and enhances signal clarity, enabling clearer communication even in crowded band conditions.

The QRP20 is equipped with an internal speaker as well as a headphone jack for private listening. It also features a built-in keyer for CW (Continuous Wave) operation, making it versatile for various modes of amateur communication including voice and Morse code.

Powering the QRP20 is effortless, as it can be run off a standard 12V power supply or a rechargeable battery, giving operators flexibility in power sourcing. Whether during portable activations or in a home setup, the QRP20 is adaptable to different operating situations.

In conclusion, the Ramsey Electronics QRP20 is a remarkable choice for amateur radio users who value portability, versatility, and performance. Its efficient design, solid technology, and ease of use make it a compelling addition to any operator's gear, offering a satisfying QRP experience while staying connected with a global community of radio enthusiasts.
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