LMR-400-75-DB cable is a Flexible Low Loss, 75 ohm Coaxial cable, supplied in any length – manufactured by Times Microwave Systems and available from McGill Microwave – Authorised Distributor of all Times Microwave products.
LMR-400-75-DB Coaxial cable is a very popular product within the Times Microwave LMR coaxial cable range. The LMR range is recognised globally as the industry standard ultra low loss, flexible, low cost, lightweight, DC – 6GHz coaxial cable solution for many RF applications. This is also backed up by the best warranty and technical support in the business.
LMR-400-75-DB is the 75 ohm, Water Blocked version of the 50 Ohm LMR-400 cable.
LMR-400-75-DB is the most popular coaxial cable in the industry due to its excellent reliability, unsurpassed flexibility and ultra low attenuation. The LMR-400-75-DB cable has loss figures comparable to the extremely rigid corrugated coaxial cables however manages to achieve similar flexibility to that of high loss RG Cables.
The LMR-400-75-DB Series, Manufactured by Times Microwave Systems, has a very similar make up to the standard LMR-400-75 series and uses the exact same LMR® connector range, however there is one critical difference.
In a normal scenario, if the outer jacket of a coaxial cable were to be cut for any reason – or damaged by wildlife , this would leave the cable with a potential leak path, directly leading to system performance degradation problems caused by increases of attenuation due to internal corrosion over time – especially if the cable was installed vertically as the moisture would travel down the cable with gravity.
The significant advantage of the LMR-400-75-DB cable is that in the event of the cable outer jacket being damaged, the blocking agent flows to the area where the outer jacket has been damaged and effectively re-seals the cable – ensuring that the ingress threat is localised to the small area where moisture has entered the cable and prevents any further moisture ingress.
Between the tinned copper overall braid and the polyethylene jacket, there is a highly flexible water sealing compound. This acts as a fully sealed, protective secondary barrier should the jacket integrity be compromised anywhere along the cable.
The LMR-DB coaxial cable product series can therefore be used in any outdoor application, including underground and saturated environments.
This is achieved due to the cable construction specifications. The centre conductor uses a high conductivity, Bare copper clad covered aluminium centre conductor material. The dielectric is nitrogen injected, foamed, closed cell, Polyethylene which helps achieve 85% Velocity of Propagation. The Dielectric has a Aluminium foil outer conductor, which is chemically bonded on to it. Due to the cable construction, The attenuation is significantly lower as compared to single shielded coaxial cables.
All standard LMR coaxial cable comes with a UV resistant, PE Jacket. This helps to ensure the cable jacket can withstand harsh outside environments and UV rays from sunlight, this is designed to last for up to 20 years of outdoor service.
LMR-400-75-DB is designed to operate excellent from DC – 6GHz. For any frequency band at VHF and above LMR is the obvious choice.
Should you find your RF system operates at above 1GHz, LMR is once again, your best option, as RG cable typically isn’t compatible with any frequency in excess of 1GHz.
Max Operating Frequency: 2.5GHz
Velocity of Propagation: 85%
Dielectric Constant NA 1.38
Impedance ohms 75
Capacitance pF/ft (pF/m) 15.9 (52.3)
Inductance uH/ft (uH/m) 0.090 (0.29)
Shielding Effectiveness dB >90
DC Resistance
Inner Conductor ohms/1000ft (/km) 2.50 (8.20)
Outer Conductor ohms/1000ft (/km) 1.65 (5.4)
Voltage Withstand Volts DC 2000
Jacket Spark Volts RMS 5000
Peak Power kW 10
LMR® is a registered trademark of Times Microwave Systems