How to choose a coaxial cable manufacturer: conductor, shield, listing

Search for a coaxial cable manufacturer and the first page mixes two different industries. One builds 50 Ω RF and microwave cable for radios, wireless gear, and test benches. The other builds 75 Ω video and broadband cable, RG6, RG59, and RG11, for CATV, CCTV, satellite, and antenna runs. Both say “coax,” and buying from the wrong one is the first mistake. The second is subtler: two reels of RG6 can look identical and differ in the metal at the center, the amount of braid around it, and whether the fire listing printed on the jacket is real. Here is how to pick the right kind of maker, and how to check what you are actually getting.

Two kinds of coax maker

BLUF: decide the impedance first. If the cable carries video, broadband, satellite, or CCTV signal, you need a 75 Ω maker. If it feeds a transmitter, an antenna on a radio, or a piece of test equipment, you need a 50 Ω maker.

Kestner is a 75 Ω maker. If your job is 50 Ω RF or microwave, a specialist RF house is the right counterparty, and we will tell you so rather than quote it.

The center conductor: where the cost is cut

BLUF: ask what metal is at the center, and make sure it matches the job. This is the one spec that changes both price and performance, and it is invisible once the cable is in the jacket.

Three conductors show up in 75 Ω coax:

• Copper-clad steel (CCS). A steel core with a copper skin. It is the normal conductor in CATV drop cable, and the ANSI/SCTE 74 drop-cable spec allows it, because at broadband frequencies the signal travels in the outer copper layer (skin effect) and the steel adds pull strength. It is cheaper than solid copper and fine for RF.
• Solid bare copper. The right choice when the coax also carries DC power or low-frequency signal: satellite runs that power the LNB on the dish, multiswitch feeds, and long analog CCTV runs. Steel has far higher DC resistance than copper, so on those runs CCS drops voltage and signal.
• Copper-clad aluminum (CCA) sold as copper. This is the fraud, the same one that shows up in cheap Ethernet cable. It is lighter, cheaper, and more brittle, and it fails the resistance a copper spec implies.

The check takes seconds. Strip an inch and hold a magnet to the center conductor: it sticks to copper-clad steel and does not stick to solid copper. Scrape the conductor with a blade: silver-white metal under a thin copper skin is aluminum. Do both on a sample from the actual lot, not the sample that came with the quote.

Shield, dielectric, and impedance

BLUF: “high shielding” means nothing on a quote. Ask for the layer count and the braid coverage in percent, and ask how impedance is held along the length.

• Shield layers. Standard RG6 is dual shield: one foil and one braid. Tri-shield adds a second foil. Quad-shield is foil, braid, foil, braid. More layers reject more noise, which matters in electrically busy buildings and near motors or RF sources, but they make the cable larger and stiffer and need matching connectors.
• Braid coverage. Stated as a percentage of the core the braid covers. Ask for the number on the spec sheet, and check that the braid metal (aluminum, tinned copper, or bare copper) matches what you were quoted.
• Dielectric. Gas-injected foam polyethylene is standard on modern RG6. What matters is that it is concentric and consistent, because the dielectric sets the impedance. An off-center core shows up as reflections on a sweep test, not on a continuity check.

Jacket and fire listing

BLUF: inside a building, the jacket needs a real fire listing for the space it runs through. Ask for the listing, then verify it yourself.

Coax for CATV and antenna distribution is covered by NEC Article 820, with its own ratings: CATVP for plenum spaces, CATVR for risers, and CATV for general use. Communications-cable ratings can substitute, so a CMP, CMR, or CM listing is also acceptable in the matching space. The CATV cable standard behind the listing is UL 1655. Outdoors, look for a UV-resistant PE jacket. For burial, ask for a flooded (gel-filled) direct-burial construction. For aerial drops, ask for an integrated messenger wire.

A print legend that says “UL” is not the same as a listing. The legend should name the rating and carry a listing reference you can check against UL Product iQ. If the supplier cannot give you a listing you can look up, the jacket is a claim, not a rating.

Bulk spool or connectorized

BLUF: decide early whether you are buying cable or finished drops, because it changes the supplier’s process, the MOQ, and what you have to inspect.

Bulk on the spool is priced by the foot and the reel length (500 ft and 1,000 ft boxes and reels are common), with MOQ driven by the jacket color, print legend, and conductor spec. Custom print legends and private-label boxes are a normal request at volume.

Connectorized drops add a termination process to the quote. Specify the connector (F, BNC, or RCA), whether it is compression, crimp, or twist-on, the length and tolerance, and the test. Compression F connectors matched to the exact cable (RG6 dual vs quad shield take different sizes) are the usual standard for professional installs. A drop that is terminated on the line should come with a continuity and short test on every piece.

What to demand before the PO

So, how do you choose

Start with the impedance: 75 Ω for video, broadband, satellite, and CCTV; 50 Ω for RF transmit, wireless, and test. Then judge a 75 Ω maker on what is inside the jacket: the center conductor matched to the job, braid coverage stated in percent, consistent impedance, a fire listing you can verify, and an origin record per lot. The same discipline applies to Ethernet cable, where the shortcut is also hidden inside the jacket. If you want 75 Ω coax built to that spec, bulk or connectorized, send us the spec and the run and we will quote it with the conductor, shield, and listing written down, and the coax options to match.