INTRODUCTION TO THE PR100

This amplifier is a truly necessary piece of equipment for your 2 meter receive applications. With 16dB of gain, you mount this up on your mast on the antenna to boost those weak signals to a receivable level. This results in clear, unbroken reception, and a more pleasant listening experience.

The filtering of the preamplifier is narrow enough only to allow the desired frequency band through, while rejecting all others. This prevents many problems associated with interference such as intermodulation and front end overload. Having such a narrow bandwidth also reduces background noise that would normally be present in wider band amplifiers.

Hookup is very simple in that the unit is powered through the same cable that you receive your signals through. It is possible to ‘feed’ the 12VDC up the coax cable to the preamplifier. No new wires to run and makes for less weatherproofing.

The PC board was designed to fit within a 1 1/2” PVC pipe, so a simple enclosure could be created out of one piece of pipe and two endcaps. Glued together it can make for the perfect weatherproof enclosure.

HOW IT WORKS

There really isn’t much to the preamplifier if you look to the schematic at the right. It mostly consists of filtering, and has only one active part, Q1. We will start from the Antenna end of the preamp, and then on to the receiver end.

J1 and J2 is where the user can connect two different antennas. Some people recommend that you use two turnstile antennas at right angles to each other for good satellite imaging, if you’re using this with a weather satellite receiver. This allows for good coverage of the horizons. Normally you will only use one of these jacks.

From these jacks the unfiltered RF passes through C6, into the bandpass tank circuit consisting of inductor L3 and capacitor C8. This tank circuit and the next two are eventually tuned to be centered at 145 MHz. C4 allows some of the RF from the first tank circuit to be allowed into the next, but is very small in capacitance to offer a large reactance (resistance to AC). This high reactance allows the tank circuits to perform their jobs better by giving them a higher Q factor. This means that the spectrum of RF the tank circuits will allow through becomes narrower due to the high Q.

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Ramsey Electronics manual Introduction to the PR100, HOW IT Works
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PR100 specifications

The Ramsey Electronics PR100 is an advanced, yet user-friendly frequency counter designed for amateur radio operators, electronics enthusiasts, and professionals alike. This innovative device is specifically crafted to accurately measure the frequency of various signals, making it a vital tool for anyone involved in RF (radio frequency) work.

One of the most notable features of the PR100 is its wide frequency range, which spans from 1 MHz to 1.5 GHz. This extensive capability allows users to measure a variety of signals, from lower amateur bands to higher frequencies often used in commercial equipment. Its high sensitivity is complemented by a low noise floor, ensuring that even weak signals can be detected and measured accurately.

The display on the PR100 is a clear LED readout that offers real-time frequency monitoring. Users can easily track frequency changes and make timely adjustments to their equipment, enhancing overall performance. The device also includes a peak hold feature, allowing users to capture the highest frequency signal for better analysis.

To accommodate a variety of applications, the PR100 supports different measurement modes, including continuous count and gated count. Continuous counting is essential for real-time monitoring environments, while gated counting is particularly useful for pulse signal analysis, allowing the user to measure pulses within a specified time window.

The PR100 boasts a simple, intuitive user interface. Its ergonomically designed controls facilitate seamless navigation through functions, making it accessible for both beginners and seasoned experts. The device also includes a BNC input for easy connection to antenna systems or other RF sources.

Moreover, the PR100 is built with portable power options in mind. It can be powered by standard AA batteries or an external DC power source, ensuring flexibility for fieldwork or in-lab use.

In terms of technologies, the PR100 utilizes advanced digital processing techniques to ensure precision and reliability. Its internal circuitry is engineered to minimize signal degradation while delivering high-quality measurements.

The construction of the PR100 reflects a blend of durability and lightweight design, making it a dependable companion for all RF endeavors. With its comprehensive features, user-friendly interface, and robust design, the Ramsey Electronics PR100 stands out as a valuable tool for anyone working with frequencies in the ever-evolving world of electronics.
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