RF Cable Assembly Specification Checklist for Procurement Engineers

Application and Basic Specifications to Confirm

Before the detailed RF cable assembly specification checklist begins, procurement engineers need to describe the application in a way that a supplier can quote and review. The inquiry should make clear what the cable connects, such as an antenna port, RF module, communication board, test instrument, cabinet interface, vehicle unit, or outdoor enclosure. It also needs to show where the cable will sit inside the product, such as inside a device housing, on a panel port, between two modules, near an antenna, inside a rack, or along a fixed cable route.

The basic specification should also include the project source. A repeat order may only need the existing part number, approved drawing, connector ends, cable length, and packing requirement checked again. A new RF cable procurement request usually needs more details, including the equipment port, target cable route, available space, whether the cable is a single coaxial cable assembly or part of a cable harness, and whether the buyer needs a standard RF cable assembly or a custom RF cable assembly. These application details create the starting point for the next specification items, without mixing them with the later checks for frequency, impedance, connector structure, cable type, environment, and test data.

Frequency Range and Impedance

Enter the working frequency and system impedance as fixed items in the RF cable specification. A 2.4 GHz antenna jumper, a 5G communication module cable, a test instrument lead, and a TV signal coaxial cable assembly may use different impedance and connector versions. Many communication, antenna, and RF test links use 50 Ω RF cable assemblies. Video, broadcast, and some television signal links often use 75 Ω coaxial cable assemblies.

SMA, BNC, N Type, and TNC can appear in different impedance or frequency versions. For reference, SMA is often specified up to DC to 18 GHz, N Type is often specified up to DC to 11 GHz or DC to 18 GHz depending on the series, and standard BNC RF versions are commonly selected around the lower gigahertz range.

Connector Details in the Specification

The connector field in an RF cable assembly specification needs more than “SMA cable” or “BNC cable.” It needs the connector type on both ends, the impedance version, gender, body style, and mounting method. For example, SMA is normally a 50 Ω threaded connector used up to DC to 18 GHz, while BNC can be supplied in 50 Ω or 75 Ω versions and is commonly selected around the lower gigahertz range. TNC adds a threaded coupling and is often specified up to DC to 11 GHz, with extended designs reaching DC to 18 GHz. FAKRA is usually a 50 Ω coded connector for automotive and module based RF links, with many versions working up to 6 GHz.

For a clean RF cable procurement request, write the connector ends in the same order every time: interface, gender, orientation, mounting style, and special version. A useful line can read “SMA male straight to SMA female bulkhead,” “BNC male right angle to TNC male straight,” “N Type male to SMA male,” or “FAKRA code Z straight to FAKRA code Z right angle.” If the cable passes through a panel, add the panel mounting style and available panel thickness. If space is tight, mark straight or right angle at the connector end. If the device uses reverse polarity, snap on coupling, bayonet coupling, or a threaded RF connector adaptor, write that in the same connector line rather than leaving it for later confirmation.

If you need a structured way to confirm connector type, impedance, gender, cable size, and working environment, please refer to our article How to Choose the Right RF Connector.

Cable Type, Loss, and Routing Space

Cable type is one of the first items to write into the RF cable assembly specification. A short internal coaxial jumper cable may use RG 316 or a small micro coaxial cable such as 1.13 mm or 1.37 mm when the route is close to a board or module. Larger cables change the layout quickly. RG 58 is about 0.195 inch in outer diameter, while LMR 400 is about 0.405 inch. That size difference affects connector size, bend space, panel clearance, and how easily the cable can be routed inside an enclosure.

Loss level can be handled in the same line. For a short cabinet link, small diameter and flexible routing may matter more than a very low attenuation cable. For a longer antenna feed, outdoor run, or high frequency path, the RFQ should name the low loss coaxial cable type and the insertion loss target at the working frequency. If the route is fixed, semi rigid or conformable cable can keep a formed shape. If the cable needs to bend around a module, panel, or housing wall, flexible coaxial cable is usually easier to assemble. A clear custom coaxial cable assembly request can list cable type, outer diameter, bend radius, shielding, jacket material, and low attenuation requirement before the sample is made.

If you need help comparing low loss coaxial cable options for longer routes or higher frequency links, please refer to our article How to Choose a Low Loss Coaxial Cable.

Environmental and Mechanical Requirements

For an indoor cabinet jumper, the request may only need cable routing space, bend direction, and strain relief. For an outdoor RF cable assembly or a panel mounted antenna cable, the same line may need IP67 or IP68 sealing, operating temperature range, UV exposure, moisture, salt spray, oil contact, and corrosion risk. IP67 SMA bulkhead assemblies are commonly built as 50 Ω RG 316 cable assemblies and can be specified up to DC to 3 GHz, while compact IP67 micro coaxial versions may reach DC to 6 GHz depending on the connector and cable set.

Mechanical details also belong in this part of the RF cable assembly checklist. A vibration resistant RF cable may need a locking interface, heat shrink, boot, overmold, armor, or fixed cable clamp near the connector. A bulkhead RF connector needs panel thickness and nut position. A right angle connector works better when the cable exits close to a wall, module, or enclosure edge. If the cable route pulls on the connector during assembly, the RFQ can mention strain relief and cable fixing method before the sample is built.

Electrical Performance Before Sample Approval

Sample approval should include the electrical limits that match the project level. For a short internal coaxial jumper, basic continuity, impedance, insertion loss, and VSWR may be enough. For a high frequency test lead, antenna feeder, cellular link, or phase stable cable assembly, the sample file needs clearer limits for VSWR, return loss, insertion loss, phase stability, shielding effectiveness, and power handling. Precision microwave cable assemblies can use impedance control as tight as 50 ± 1 Ω, while some high performance coaxial cable assemblies are specified for frequencies up to 110 GHz.

The RF cable test report also needs to match the working frequency of the assembly. A VSWR value or insertion loss value at the wrong frequency does not tell much about the finished cable in the target system. For cellular base station, antenna, high power, or distributed antenna projects, low PIM data may also belong in the sample review. A practical sample approval file can show the measured frequency range, VSWR or return loss, insertion loss, impedance, connector configuration, and cable length, so the procurement team can compare the sample with the approved RF cable specification before moving to bulk orders.

Length, Tolerance, and Drawing Control

Length needs a defined measuring method on the RF cable assembly drawing. A 300 mm cable can mean finished assembly length, cable cut length, or distance between connector reference points. Straight connectors are usually easier to measure, while right angle connectors need a clear centerline or cable exit reference. Standard RF cable assemblies may be listed in fixed lengths such as 6 inches, 12 inches, 24 inches, 1 meter, 2 meters, or longer sizes. Custom RF cable assembly orders need the finished length and cable length tolerance written on the same drawing, especially when the cable passes through a panel, rack space, or compact device housing.

Drawing control also covers parts that are easy to overlook during RF cable procurement. The drawing can show connector orientation, right angle direction, stripping length, heat shrink length, boot position, label text, batch code, cable harness number, and packing label. Short assemblies need extra attention when one end is right angle, because a small change in connector clocking can move the cable exit to the wrong side of the module or panel.

Final RFQ Checklist Before Ordering

RFQ Item	What to Confirm
Application	Antenna link, RF module, cabinet jumper, test cable, outdoor enclosure, vehicle unit, or OEM cable harness
Frequency Range	Working frequency and highest operating frequency
Impedance	50 ohm or 75 ohm system impedance
Connector Ends	Connector type, gender, straight or right angle, mounting style, polarity
Cable Type	RG cable, micro coaxial cable, low loss coaxial cable, semi rigid cable, or conformable cable
Length and Tolerance	Finished length, measuring method, and cable length tolerance
Routing Space	Bend direction, available space, cable exit direction, and panel clearance
Environment	Temperature range, waterproof or sealed requirement, vibration, UV, moisture, oil, or corrosion risk
Drawing Details	Drawing number, revision, right angle orientation, stripping length, heat shrink, label, and packing requirement
Test Requirement	VSWR, return loss, insertion loss, continuity, impedance, phase stability, or low PIM if needed
Compliance	RoHS, REACH, material confirmation, or export documentation
Order Details	Quantity, lead time, sample approval record, and repeat production reference

FAQ