Category Archives: كابل

Pick the wrong RF connector and you create a mismatch that costs you signal, adds insertion loss, or fails mechanically in the field. N-Type, SMA, and BNC connectors are all used on 50Ω coaxial systems, they all look broadly similar to the uninitiated, and they are absolutely not interchangeable.

This guide covers the real differences — frequency limits, coupling mechanism, weatherproofing, size, and which connector belongs where — so you can make the right call on the next installation or procurement.

Quick Reference: N-Type vs SMA vs BNC

N-Type Connector

N-Type (or Type-N) was developed in the late 1940s for military communications — a lineage that tells you something about its design priorities. It is a large, threaded, weatherproof connector built for outdoor and high-power RF applications. The hex coupling nut locks securely and resists vibration, which is why it is still the connector of choice for antenna feedlines and VSAT installations decades later.

N-Type Specifications

Where N-Type Is Used

VSAT IFL cable runs — The intermediate frequency link between the ODU and modem operates at L-band (950–2,150 MHz). N-type is the standard interface at both ends. At 1–2 GHz the connector’s 11 GHz headroom is irrelevant, but its weatherproofing and robust coupling are not.

Antenna feedlines and tower work — Any run from a base station radio to an antenna uses N-type. The cable is exposed to wind, UV, and rain; the connector needs to be too.

LMR-400 and larger cables — The physical dimensions of N-type suit the larger LMR cable families. An N-type crimp connector on LMR-400 is the most common termination combination in outdoor RF installations in the GCC.

High-power RF — When you are driving a power amplifier into an antenna and the cable carries high power, N-type’s voltage rating and low contact resistance matter. SMA and BNC are not appropriate at high power levels.

SMA Connector

SMA (SubMiniature version A) was designed in the 1960s for microwave frequencies where physical size affects electrical performance. It is significantly smaller than N-type, uses a precision 1/4″-36 threaded coupling, and is rated to 18 GHz in standard form — making it the default for microwave and laboratory applications.

SMA Specifications

Where SMA Is Used

GPS and GNSS equipment — Nearly all GPS receiver modules and antennas use SMA or RPSMA. If you are running GPS cables to a VSAT terminal, modem, or asset tracking unit, you are dealing with SMA.

Indoor radio and wireless equipment — Small form-factor radios, modems, and routers in the 2.4 GHz, 5 GHz, and sub-6 GHz bands use SMA or RPSMA.

Test and measurement above 11 GHz — For measurements in Ku-band and above, SMA is the only option among these three connectors.

BNC Connector

BNC (Bayonet Neill–Concelman) is quick to connect and disconnect — one quarter-turn to lock — which is its main advantage. It was widely used in legacy radio, test equipment, and broadcast video. The bayonet mechanism is fast but does not thread, so it cannot be torqued down and provides no environmental sealing.

BNC Specifications

Where BNC Is Used

Test equipment and oscilloscopes — BNC is the standard probe interface on oscilloscopes and most benchtop instruments below 1 GHz.

Broadcast video (75Ω) — The 75Ω BNC variant is the universal interface for HD-SDI video cabling. These look identical to 50Ω BNC but are not electrically compatible.

Network timing and 10 MHz reference signals — GPS disciplined oscillators (GPSDO) and network timing equipment typically output 10 MHz reference on BNC.

How to Choose: Decision Guide

By Application

By Frequency

By Environment

Adapters: When You Have the Wrong Connector

Adapters between connector types are available and widely used, but they add insertion loss and reflections at higher frequencies. Keep adapters to one per signal path and do not use them on a connector you mate and unmate frequently — the wear happens on the adapter body.

What Cables Work With Each Connector

For VSAT and radio installations, the Times Microwave LMR series covers most cable runs. Here is how the connectors map to common LMR cables:

Summary

N-Type, SMA, and BNC serve different roles in RF systems. N-Type is the outdoor, high-power, weatherproof choice for antenna feedlines and VSAT IFL runs. SMA handles microwave frequencies up to 18 GHz and belongs on indoor equipment, GPS cabling, and test benches. BNC is a legacy quick-connect connector suited to sub-4 GHz test equipment and broadcast video. Using the wrong one means you are either over-specifying and paying for it, or under-specifying and paying for it later in a fault call.

A poorly terminated connector is the number one cause of signal degradation on an otherwise well-designed RF installation. LMR cables — particularly LMR-400 — are used on VSAT IFL runs, radio base station feedlines, and outdoor antenna installations where the connector is exposed to weather, vibration, and long-term stress. Getting the crimp right the first time saves you a troubleshooting call six months later.

This guide walks through the complete termination process for LMR-400 with an N-type crimp connector — the most common combination in VSAT and radio work — and covers the critical dimensions, tools, and mistakes that separate a reliable termination from a future fault.

What You’ll Need

Getting the right tools matters more than most people realise. Undersized or worn tooling causes crimp failures that are invisible to the eye but catastrophic for RF performance.

Strip Dimensions for LMR-400 N-Type Crimp

These are the published Times Microwave strip dimensions for LMR-400 with a standard N-type crimp connector. Write these on your tool bag if you do this regularly.

Step-by-Step: N-Type Crimp on LMR-400

Common Mistakes

Testing Your Termination

Every terminated connector should pass three checks before the cable goes into service:

Connector Compatibility Quick Reference

Always match the connector spec to your cable. Using an LMR-400 connector on LMR-600 is the most common ordering mistake.

For a full cable series comparison, see the Times Microwave LMR Series guide.

FAQ

Can I reuse an LMR connector after removing it?
No. Once a crimp ferrule has been compressed, it cannot be re-used. Cut the connector off, re-prepare the cable end, and use a new connector.

What’s the minimum pull-out force for a properly crimped LMR-400 connector?
Times Microwave specifies approximately 45 kg (100 lbs) minimum pull-out strength for a correctly crimped LMR-400 N-type. If yours pulls off with hand force, the crimp failed.

Can I use a standard N-type connector meant for RG-8 on LMR-400?
No. LMR-400 has a different OD, braid construction, and dielectric. Using an RG-8 connector produces a mechanically and electrically poor termination. Always specify connectors made for LMR-400.

How do I know if my crimp tool die is worn?
A worn die produces ferrules that are out-of-round or show uneven hex faces. Check with calipers — if in doubt, replace the die. A worn die is cheaper to replace than a failed installation.

What’s the difference between silver and gold centre pins?
Silver-plated pins are standard for VSAT work. Gold pins appear in some lower-frequency or high-reliability connectors. For LMR-400 N-type in VSAT IFL work, silver-plated is correct.

Every RF and satellite engineer hits this fork eventually: you’re designing a cable run and someone asks, “should we go fiber?” The right answer depends almost entirely on what the cable is carrying. If it’s connecting a modem to a BUC or LNB, the answer is always coaxial — no exceptions. If it’s a data backbone between buildings, fiber is almost certainly the better call.

This guide breaks down the key differences between fiber optic and coaxial cable and gives you a clear framework for choosing the right one every time.

What Is Coaxial Cable?

Coaxial cable carries RF signals as electrical waves along a center copper conductor, insulated from a surrounding braid or foil shield by a dielectric foam core. The shield keeps the signal contained and blocks external interference from entering. An outer PE or PVC jacket provides mechanical and weather protection.

In VSAT and satellite applications the most common types are LMR-400 (standard Ku-band IFL, runs to ~30m), LMR-600 (medium runs to ~60m), LMR-900 (long runs to 80m+), and legacy RG214. For broadcast and CATV distribution, 75Ω RG6 is common.

The capability that makes coaxial indispensable for satellite work: it carries DC power alongside the RF signal. The same cable that carries your IF signal from modem to LNB also delivers the 13V or 18V DC that powers the LNB — plus the 22 kHz polarisation tone — and the 24–48V DC that drives the BUC. No other single cable can do this.

What Is Fiber Optic Cable?

Fiber optic cable carries signals as pulses of light through a glass core, surrounded by cladding (a lower-refractive-index glass layer that traps light inside by total internal reflection), a protective buffer coating, and an outer jacket. There are no copper conductors — signals travel at the speed of light with virtually no attenuation over distance.

Two main types exist: single-mode fiber (SMF, OS1/OS2) for long-distance runs up to 40+ km, and multi-mode fiber (MMF, OM3/OM4) for shorter data links up to ~300m. For telecom and data center backbone, SMF OS2 is the current standard.

The defining advantages: attenuation of just 0.2 dB/km at 1550 nm (vs approximately 30 dB/100m for LMR-400 at Ku-band), complete immunity to electromagnetic interference, and effectively unlimited bandwidth. The defining limitation: fiber cannot carry DC power. Any powered equipment at the far end requires a separate power cable.

Fiber Optic vs Coaxial Cable: Full Comparison

When to Use Coaxial Cable

When to Use Fiber Optic Cable

Why VSAT Always Uses Coaxial — Without Exception

Frequently Asked Questions

The cable run between your VSAT outdoor unit and your modem is called the IFL — Intermediate Frequency Link. It carries the satellite signal after the LNB has downconverted it from Ku or C-band to L-band (950–2150 MHz), and it carries the uplink signal from your BUC before transmission.

Get the IFL cable wrong — wrong type, wrong length, connectors not properly terminated — and your link budget suffers before a single packet reaches the satellite. This guide covers what the IFL is, how to choose the right cable, how to calculate loss for your specific run, and what maximum lengths apply to each cable type.

What Is an IFL Cable?

IFL stands for Intermediate Frequency Link. It is the coaxial cable connecting two points in a VSAT system:

The LNB downconverts the received satellite signal from Ku-band (10.7–12.75 GHz) or C-band (3.7–4.2 GHz) to L-band (950–2150 MHz). The BUC upconverts the transmit signal from L-band to Ku or C-band. The IFL cable carries both of these L-band signals simultaneously — receive down, transmit up — through a single coax run. The IFL also carries DC power from the modem to the LNB and, in most systems, carries the DiSEqC or tone commands that control LNB polarisation and band switching.

IFL Cable Specifications

Frequency Range

The IFL operates at L-band: 950 MHz to 2,150 MHz for most Ku-band VSAT systems.

Impedance and Connectors

All IFL cables are 50Ω. Do not use 75Ω cable (standard satellite TV cable) for IFL runs — the impedance mismatch introduces reflections and degrades signal quality. Both ends terminate in N-type connectors, the standard for VSAT IFL work. See the N-Type vs SMA vs BNC connector guide for a full comparison.

Cable Types for IFL Runs

The Times Microwave LMR series is the industry standard for VSAT IFL installations.

Attenuation at 2 GHz per 100m — visual comparison:

For a direct cable comparison, see LMR-400 vs LMR-600: Which Should You Choose?

IFL Signal Loss: How to Calculate Your Run

Attenuation accumulates with distance. Every metre of cable, every connector, and every in-line component adds insertion loss.

Total loss (dB) = Cable loss (dB/m) × Run length (m) + Connector loss × Count + In-line component losses

A good N-type connector pair adds approximately 0.1–0.2 dB. Surge arrestors add 0.3–0.5 dB each.

LMR-400 Loss Reference

LMR-600 Loss Reference

Maximum IFL Run Lengths

For runs beyond 75m on LMR-400, move to LMR-600. For runs exceeding 150m, consider relocating the modem closer to the dish or using a fibre optic IFL.

DC Power and Voltage Drop on Long Runs

The IFL cable carries DC power from the modem to the LNB (typically 13V or 18V at up to 500 mA). LMR-400 centre conductor resistance: ~1.4 Ω per 100m. At 100m with 400 mA LNB current, voltage drop ≈ 0.56V — within tolerance for most systems. At 200m+ on LMR-400, verify LNB minimum operating voltage against actual delivered voltage before commissioning.

Weatherproofing the ODU Connection

Moisture ingress at the N-type connector where the IFL meets the LNB or BUC is one of the most common causes of IFL degradation in the GCC. Weatherproof every outdoor connection on the day of installation.

Common IFL Installation Mistakes

Sourcing IFL Cable in the UAE and GCC

For professional-grade IFL installations — Times Microwave LMR-400, LMR-600, with matched N-type crimp connectors — source from a distributor carrying genuine Times Microwave product. Off-brand cable with inconsistent impedance control introduces return loss problems that are difficult to diagnose without a VNA.

Bravo Satcom carries LMR cable and RF connectors suited to VSAT IFL installations across the GCC.

Summary

The IFL cable is a critical and often underspecified component in VSAT installations. Use 50Ω LMR-series cable — LMR-400 for runs up to 75m, LMR-600 beyond that. Calculate your total IFL loss including connectors and in-line components, weatherproof every outdoor connection, and verify DC voltage delivery on long runs.

If you’re specifying cable for a VSAT antenna, two-way radio system, or any RF installation, you’ve likely hit the same question: LMR-400 or LMR-600? Both are Times Microwave Systems’ most popular flexible coax cables — low loss, UV-resistant, and built for outdoor use. The difference comes down to run length, signal loss budget, and how much space you have to work with.

This guide gives you the specs, the attenuation data, and a clear decision rule.

Physical Specs: Side by Side

The bigger conductor in LMR-600 (0.176″ vs 0.108″) is the reason it outperforms LMR-400 on signal loss — lower DC resistance means less energy dissipated as heat per foot of cable.

Signal Attenuation: The Numbers That Matter

Attenuation is measured in dB per 100 feet — the lower the number, the better. Based on Times Microwave Systems official specifications:

LMR-600 delivers roughly 35% less attenuation at all frequencies compared to LMR-400. That gap compounds quickly over longer runs.

When LMR-400 Is the Right Choice

LMR-400 is the industry standard for good reason. Choose it when:

Run length is under 30 metres (100 ft). At this distance, the loss difference between LMR-400 and LMR-600 is minimal and doesn’t justify the cost or weight difference.

You need flexibility. With a 1.0″ minimum bend radius, LMR-400 is significantly easier to route through conduit, around corners, and in tight equipment racks.

Weight matters. At 0.068 lbs/ft (vs 0.131 lbs/ft for LMR-600), LMR-400 is nearly half the weight — important for rooftop or tower installations where cable tray loading is a concern.

Budget is a factor. LMR-400 is meaningfully less expensive per metre than LMR-600, making it the practical default for short-to-medium runs.

LMR-400 is the cable of choice for most VSAT antenna-to-modem runs, two-way radio base station feeders, and short rooftop drops.

When You Should Upgrade to LMR-600

Move to LMR-600 when signal loss budget is tight:

Run length exceeds 30–40 metres (100–130 ft). Beyond this point, the accumulated loss in LMR-400 starts eating into your link margin — especially at higher frequencies (Ku-band IF at 950–1,450 MHz and above).

High-power applications. LMR-600’s larger conductor handles more RF power before thermal losses become a concern — relevant for high-wattage BUC installations where every dB matters.

You’re running at 1 GHz or above over long distances. Attenuation increases with frequency. A 60-metre Ku-band IF run at 1,500 MHz in LMR-400 loses ~7.0 dB. In LMR-600, the same run loses ~4.4 dB. That 2.6 dB difference can be the margin between a stable link and intermittent dropouts.

Maximum cable run distances: LMR-600 supports antenna cable runs up to 400 ft (120 m) without inline amplification. LMR-400 is typically limited to around 200 ft (60 m) before loss becomes unacceptable at Ku-band frequencies.

Cost and Installation

LMR-600 typically costs 30–50% more per metre than LMR-400. It’s also heavier and stiffer, requiring more careful routing and stronger support hardware — cable trays and support clamps need to account for the increased weight (0.131 lbs/ft vs 0.068 lbs/ft).

Connectors are cable-specific — don’t mix LMR-400 and LMR-600 connectors. If you’re terminating in the field, LMR-600 requires a larger stripper tool and more robust crimp or compression fittings. Both cables accept Times Microwave Systems EZ push-on connectors, which eliminates soldering on site.

The Simple Decision Rule

If you’re ever in doubt, calculate your total path loss budget: add up the cable loss, connector insertion loss (~0.1 dB per connector), and any other passive components. If the total pushes you within 1–2 dB of your link margin, upgrade to LMR-600.

Frequently Asked Questions

Can I mix LMR-400 and LMR-600 in the same run?

Yes, but only with proper barrel adapters. Keep the LMR-600 section on the longer runs and use LMR-400 for short flexible jumpers at each end.

Are LMR-400 and LMR-600 connectors interchangeable?

No. Each cable requires its own connector size. LMR-400 and LMR-600 both accept N-type, TNC, and SMA connectors — but in their respective sizes. They are not physically compatible with each other.

Which cable is better for outdoor VSAT installations in hot climates?

Both use a black UV-protected polyethylene jacket rated for −40°C to +85°C, making them suitable for the UAE and GCC climate. For buried runs, specify LMR-DB (watertight/flooded version) from Times Microwave Systems.

Does LMR-600 need different support hardware?

Yes. At 0.131 lbs/ft, LMR-600 requires stronger cable trays and more frequent support points — approximately every 18–24 inches on horizontal runs vs every 24–36 inches for LMR-400.

Shop LMR Coaxial Cable at Bravo Satcom

إذا كنت تبحث عن كابل متحد المحور عالي الجودة ، فربما تكون قد سمعت عن LMR400. إنه خيار شائع لمجموعة متنوعة من التطبيقات ، بما في ذلك شبكات Wi-Fi والشبكات الخلوية وراديو الهواة والمزيد. لكن أحد أهم الاعتبارات عند اختيار كابل متحد المحور هو الخسارة أو التوهين الذي يحدث أثناء انتقال الإشارة عبر الكابل. في هذا المنشور ، سنناقش خسارة LMR400 وما تحتاج إلى معرفته لاتخاذ قرار مستنير.

ما هو LMR400؟
LMR400 هو نوع من الكابلات المحورية التي تحتوي على موصل مركزي نحاسي صلب ، وعزل من البولي إيثيلين الرغوي ، وتدريع مزدوج يتكون من رقائق الألومنيوم المستعبدة وجديلة نحاسية معلبة. يبلغ قطر الكابل 0.405 بوصة (10.3 مم) ومقاومة 50 أوم ، وهي المعاوقة القياسية لمعظم تطبيقات التردد اللاسلكي. تم تصميم LMR400 للتطبيقات منخفضة الخسارة وله توهين اسمي يبلغ 6.6 ديسيبل لكل 100 قدم (30 مترا) عند 900 ميجاهرتز.

خسارة LMR400: ما مقدار التوهين الذي يحدث؟
كما ذكرنا سابقا ، تعد الخسارة أحد أهم الاعتبارات عند اختيار كابل متحد المحور. إنها كمية الإشارة المفقودة أثناء انتقالها عبر الكابل بسبب عوامل مختلفة مثل المقاومة وخسائر العزل الكهربائي والإشعاع. في حالة LMR400 ، تكون الخسارة منخفضة نسبيا مقارنة بالأنواع الأخرى من الكابلات المحورية. فيما يلي جدول مقارنة لفقدان LMR400 عند ترددات مختلفة:

كما ترى ، يزداد التوهين مع زيادة التردد. ويرجع ذلك إلى تأثير الجلد ، والذي يتسبب في انتقال الإشارة بشكل أساسي على سطح الموصل بترددات أعلى ، مما يزيد من المقاومة وبالتالي الخسارة.

العوامل المؤثرة على خسارة LMR400
يعتمد توهين LMR400 على عدة عوامل ، بما في ذلك طول الكابل وتردد الإشارة ودرجة الحرارة وطريقة التثبيت. على سبيل المثال ، إذا كان الكبل ملتويا أو مثنيا بشكل حاد للغاية ، فقد يتسبب ذلك في خسارة إضافية بسبب زيادة المقاومة. وبالمثل ، إذا تم تركيب الكبل في منطقة ذات درجات حرارة عالية ، فقد يتسبب ذلك في انهيار العزل ، مما يزيد من الخسارة.

استنتاج
LMR400 هو كابل متحد المحور شائع لمجموعة متنوعة من التطبيقات نظرا لفقدانه المنخفض وأدائه العالي ومتانته. عند اختيار كبل متحد المحور ، من المهم مراعاة التوهين أو الخسارة التي تحدث أثناء انتقال الإشارة عبر الكابل. يعد فقدان LMR400 منخفضا نسبيا مقارنة بالأنواع الأخرى من الكابلات المحورية ، مما يجعله خيارا رائعا لتطبيقات المسافات الطويلة وعالية التردد. ومع ذلك ، من المهم أيضا مراعاة العوامل التي يمكن أن تؤثر على الخسارة ، مثل طول الكابل وتردده ودرجة حرارته وطريقة التثبيت ، لضمان الأداء الأمثل.

نأمل أن يكون هذا المنشور قد ساعدك على فهم خسارة LMR400 وما تحتاج إلى معرفته لاتخاذ قرار مستنير. إذا كان لديك أي أسئلة أو تعليقات ، فلا تتردد في تركها أدناه.