This is a specific type of RF (Radio Frequency) adapter cable assembly designed to connect devices with different standard coaxial connectors while ensuring minimal signal loss. This cable assembly is essential in professional and advanced amateur radio applications where reliability and compatibility between various pieces of equipment are necessary.
The assembly is defined by its three key components: the SMA Male connector, the N Male connector, and the interconnecting LMR-200 coaxial cable.
Component Breakdown and Technical Features
1. SMA Male Connector
The SMA (SubMiniature version A) connector is a common, small-format coaxial connector.
Gender and Polarity: It is a Male connector, meaning it has a central pin and internal threads. It connects to an SMA Female jack (which has a center sleeve/hole and external threads).
Application: SMA is widely used on devices requiring small, semi-precision coaxial interconnects, such as Wi-Fi routers, GPS receivers, cellular modems, RF test equipment, and miniature radio modules.
2. N Male Connector
The N (Type N) connector is a larger, medium-sized coaxial connector designed for robust, high-power, and high-frequency use.
Gender and Polarity: It is a Male connector, featuring a central pin and internal threads. It connects to an N Female jack.
Application: N-Type connectors are typically used in more demanding installations, including base stations, external antennas (especially high-gain directional antennas), broadcast equipment, military hardware, and high-power laboratory test equipment. They are favored for their excellent performance up to 11GHz or higher, and their superior waterproofing capabilities.
3. LMR-200 Coaxial Cable
LMR-200 is a specific type of Low Loss Coaxial Cable manufactured by Times Microwave Systems (or its equivalents from other manufacturers). The designation "200" refers to its approximate diameter (0.195 inches or 5mm.
Low-Loss Performance: LMR-200 uses a solid center conductor and a multi-layered foil and braid shielding to achieve significantly lower signal attenuation (loss) than standard cables like RG-58 or RG-174. This is crucial for maintaining signal integrity over runs where devices are spaced apart.
Flexibility: It offers a good balance between low loss and flexibility, making it easier to route than much stiffer, higher-performance cables (like LMR-400), while still outperforming thinner, highly flexible cables.
Impedance: LMR-200 has a standard characteristic impedance of 50 (Ohms), matching virtually all professional and commercial RF communication systems.
Common Usage Scenarios
This specific cable assembly is used as an adapter, jumper, or pigtail cable in situations where two different connector standards must be reliably linked.
Connecting Small Modems to Large External Antennas:
Scenario: Linking a cellular modem, Wi-Fi gateway, or other device with an SMA Female port to a high-gain outdoor antenna (mounted on a roof or tower) that terminates in an N Female jack.
Function: The LMR-200 cable bridges the distance while the N Male end connects to the large antenna and the SMA Male end connects to the small modem.
Test and Measurement:
Intermediate Jumper:
Scenario: In an installation involving long, thick, very low-loss cable runs (e.g., LMR-400), this shorter LMR-200 jumper can be used near the equipment (SMA end) to provide flexibility without sacrificing much loss, or near the antenna (N end) to transition between equipment.
Cable Performance Comparison (LMR-200)
The choice of LMR-200 cable is a deliberate compromise between size, flexibility, and signal loss. The attenuation for LMR-200 is generally around:
0.15dB at 900MHz
0.25dB at 2.4 GHz
This makes it an excellent choice for short to moderate-length runs where minimizing loss at Wi-Fi or cellular frequencies is important.
