If you're studying this manual before deciding to try this Ramsey "QRP" transmitter project, perhaps the following discussion will be helpful to you. The purpose of this manual is to help you construct this Ramsey Electronics 4- stage, variable-frequency CW transmitter efficiently and successfully, not necessarily to "sell" you on the merits and fun that have been discovered in ham QRP operation. The purpose of the following discussion of power levels and signal reports is simply to assure you that your new Ramsey QRP transmitter is capable of serious, long-distance communication.

1000 WATTS vs 1 WATT: UNDERSTANDING THE DIFFERENCE

Before we move on, I would like to share with you a practical formula about transmitter power that I clung to in my younger years when I could not afford anything other than my original Novice CW transmitter, even well after I got my Extra Class license. First, some theoretical facts we should know:

•1. An "S-unit" on a receiver's S-meter or in the R-S-T system consists of a 6 - decibel increase or decrease of output power received from a transmitter.

•2. Power needs to be increased four times or 400% to result in a true 1 S- unit or 6db RST gain.

•3. Reducing output power down to 25% of previous power should result in an S- Meter or RST drop of only one 6-db unit.

•4. A 10 - decibel increase in signal strength requires a power increase of ten times!

Next, there are three practical facts to remember:

•1. The R-S-T system was designed originally for the human ear and was based on typical receiver performance of over 50 years ago.

•2. Modern receiver design permits signals which are technically "weak" in measured decibels to sound quite good (ie: 569-579) to the ear.

•3. The human ear is sensitive enough to appreciate a 1 or 2 db change in signal strength, which is why moderate changes in output power often result in more dramatic signal report changes. (In fact, the value of a

decibel was determined to be that increment of sound change which the ear could detect!)

The following example shows RST reports to be expected, in exact theory, at various power reduction levels. We will start with the classic 1000 watt station which gets a report of "10 db. over S-9" measured on the receiving station's S- meter. Assume identical dipole antennas at both stations. Our chart does not

QRP-20 • 5

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Ramsey Electronics QRP20 manual Watts vs 1 Watt Understanding the Difference
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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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