Ramsey Electronics CT255 specs

installed). Since a diode will only conduct when it is forward biased, this diode acts as a “reverse voltage” protection circuit. Diodes are often used as “one-way switches” in this manner to protect internal circuitry.

3. Identify C8, the 470 uF electrolytic capacitor (small cylindrical component coated with plastic and marked 470). Electrolytic capacitors are polarized with a (+) and (-) lead and must be installed in the correct orientation. Ordinarily, only the negative side is marked on the capacitor body with a dark band and the (-) sign clearly shown, while the PC board will usually show the (+) hole location. Use care to ensure proper polarity. See the parts diagram for proper placement. The capacitor should fit snugly down to the PC board. Save those long leads that you trim off to fashion

jumper connections later in the assembly.

4. Identify the 7805 voltage regulator IC, VR1(three lead component labeled 7805). This component is in a TO-220 package, and again proper orientation is required for correct operation. The component should be mounted so that the metal “base” of the part mounts flat to the circuit board (to avoid any problems with clearance for the case assembly). You may want to pre-bend the leads with needle-nose pliers for a proper fit. Also be sure to line up the hole in the part with the hole on the circuit board. Use caution so as not to stress the leads when inserting or soldering. Use the parts layout diagram as a guide for proper orientation. Once you have the leads soldered into place you can take the screw and nut and attach the regulator to the PC board.

5. Install C7, one of the 10 uF electrolytic capacitors (in a small cylindrical case marked 10 uF). Remember to observe polarity with those electrolytic capacitors! Check the parts layout diagram for correct orientation.

Great job up until now! Take a moment to check your previous solder joints for “opens” where the solder did not completely flow around the connection or solder bridges between closely spaced pads. It seems the best time to identify these problems is now when you’re focused on this section of the board, saving you time trying to retrace your steps later.

Let’s get to work on that counter and display section of the thermometer next.

6. Install U2, the 74HC393 14 pin IC. Make sure to align the notch or dot associated with pin one with the notch shown in the parts layout diagram. Also check to be sure all 14 pins are through the board before soldering the IC . It may be helpful to gently “rock” the IC on its side on a hard flat surface before installing to align the rows of pins so that they slide in easily. Don’t be afraid to use enough solder and heat for a good solder connection, and be extra careful not to “bridge” any solder connections together.

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CT255 specifications

The Ramsey Electronics CT255 is a versatile and advanced communication tool designed for radio enthusiasts and professionals alike. As a 2-meter FM transceiver, it is known for its robust performance and extensive feature set, making it ideal for both casual users and serious operators.

One of the standout features of the CT255 is its compact design, allowing for easy integration into various environments such as home stations or portable setups. The unit is built with user-friendliness in mind, featuring an intuitive interface with a clear display and easily accessible controls. This ensures that users can quickly tune into their desired frequencies and modify settings without extensive technical knowledge.

The CT255 operates on a frequency range from 144 to 148 MHz, providing access to the popular 2-meter amateur radio band. This frequency capability is complemented by an impressive output power of up to 25 watts, ensuring robust communication over extended distances. It also includes a built-in automatic repeater shift, which simplifies contacts through repeaters, making it an excellent choice for those looking to enhance their communication range.

In terms of technology, the CT255 employs advanced digital signal processing (DSP), which significantly improves audio clarity and reduces background noise. This makes communication clearer, even in less-than-ideal conditions. Additionally, the transceiver features an array of scanning functions, including memory scan and priority scan, allowing users to monitor multiple channels effortlessly.

The CT255 comes equipped with multiple memory channels, enabling easy access to frequently used frequencies. This feature is particularly useful for users who participate in various nets or have multiple repeaters they commonly contact. Moreover, the unit supports CTCSS and DCS tones, which adds an extra layer of privacy and reduces interference from unwanted transmissions.

Safety and durability are also key characteristics of the CT255. The robust construction ensures it can withstand the rigors of regular use, making it suitable for field operations. It is designed with heat dissipation features to prevent overheating during prolonged use, ensuring reliability during critical communications.

In conclusion, the Ramsey Electronics CT255 is a well-rounded transceiver that brings together advanced technology, user-centric design, and excellent performance. Its range of features makes it an appealing choice for radio amateurs seeking a dependable and efficient communication solution. Whether for casual chatting or emergency communications, the CT255 stands out as a reliable tool that meets the demands of modern radio users.