M.A.R.C

Updated !!

RF connectors are used to carry high-frequency signals between cables, antennas, radios, test equipment, and communication systems. Choosing the right connector is important because each type is designed for a specific frequency range, power level, size, and application.
This comparison shows several common RF connector types and their typical operating frequencies. SMA connectors offer the highest performance among the connectors shown and are widely used in Wi-Fi, GPS, satellite communication, microwave circuits, and RF test equipment. Type N connectors are larger, rugged, and commonly found in base stations, antennas, and outdoor wireless systems. TNC connectors provide threaded coupling for better vibration resistance, while SMC and MCX connectors are compact options often used in embedded RF devices and communication modules.
BNC connectors are popular in oscilloscopes, signal generators, and video equipment because they provide a quick bayonet-lock connection. SMB connectors are smaller snap-on connectors frequently used in wireless modules and compact electronics. Mini-UHF and UHF connectors are commonly found in older radio systems, amateur radio equipment, and low-frequency communication applications.
As operating frequency increases, connector design becomes more critical. Higher-frequency connectors require better impedance control, lower signal loss, and improved shielding to maintain signal integrity. Understanding the strengths and limitations of each RF connector helps engineers select the best option for reliable signal transmission in communication, networking, aerospace, broadcasting, and test-and-measurement applications.
Rohde & Schwarz

Digital modulation is a method used to send digital data, such as 0s and 1s, over communication channels like radio waves, cables, and wireless networks.
The waveforms show four common digital modulation techniques. The digital data sequence at the top is converted into different signal patterns for transmission.
In Frequency Shift Keying (FSK), the frequency of the carrier wave changes depending on whether the bit is a 0 or a 1. A higher frequency may represent a 1, while a lower frequency represents a 0.
In Amplitude Shift Keying (ASK), the amplitude or strength of the signal changes. A larger amplitude can represent a 1, and a smaller amplitude can represent a 0.
In Phase Shift Keying (PSK), the phase of the carrier wave changes to indicate different digital values. The signal keeps the same frequency and amplitude, but its phase shifts at specific points.
Quadrature Amplitude Modulation (QAM) combines both amplitude and phase changes, allowing more data to be transmitted efficiently.
FSK is simple and resistant to noise, ASK is easy to implement, PSK provides better performance in noisy environments, and QAM offers high data rates used in modern technologies such as Wi-Fi, cable internet, and cellular networks.
These modulation methods are essential for reliable digital communication systems.

Here the rotary dipole 40m band short design if you wanna try and like experiment on HF antenna, this antenna not just picture but I have made many of them myself and easy to setup at narrow land, happy homebrewer best 73..de YG1BQO

This moxon HF antenna design for 10m band, happy homebrewer best 73