The truth about professional COAX

Why professional COAX is not "just cable work"

To a layperson, a professional coaxial cable looks like a thick, stiff cable with a metal connector. In reality, it is a precision instrument. The inner conductor, the dielectric, the corrugated or braided outer shield and the PE jacket together form a transmission line that no longer keeps its impedance pure when handled incorrectly. At that point, reflections occur. Reflections lead to a higher VSWR, and a higher VSWR means power loss, heat in the transmitter and, eventually, damage to the final stage of your radio or amplifier. What starts as an invisible dent in a cable ends as an outage that costs you thousands of euros.

The five mistakes we constantly see in rushed work

1. The bending radius is exceeded

Every coaxial cable has a manufacturer-specified minimum bending radius, and it is often wider than an installer intuitively assumes. Whoever "pushes the cable around a corner" by hand invisibly kinks the dielectric. The cable still works — until it doesn't.

2. The pulling tension is ignored

Every type of feeder cable has a maximum pulling force. With a winch or just by "pulling hard", you exceed it effortlessly. The result: the inner conductor stretches, the impedance changes locally, and the problem sits in an unreachable spot in the mast or cable tray.

3. The connector is prepared incorrectly

Stripping a connector requires the right preparation tool, a correctly adjusted stripper, and a clean, flat cut that matches that specific cable type. One millimetre too deep, and the conductor is damaged. One millimetre too shallow, and the contact is unreliable. Neither shows up in a visual inspection.

4. The connector is not torqued to spec

Every connector — N-type, 7/16 DIN, 4.3-10 or other — has a specific tightening torque prescribed by the manufacturer. Whoever tightens it "firmly by hand" ends up with micro-movement in the contact after six months of weather exposure. That produces PIM (passive intermodulation), and in a mobile network PIM is the silent killer of data speeds.

5. The weatherproofing is finished sloppily

Cold shrink, mastic tape or self-adhesive rubber: each type of weatherproofing has its own procedure. Sloppy wrapping lets water run in along the connector, and water in the cable means corrosion of the inner conductor. From that point on, the cable is lost — and often the connectors at both ends with it.

6. Torsion in the cable is ignored

When pulling or mounting coaxial cable, the cable is sometimes unknowingly twisted around its own axis. That torsion stays locked in the dielectric and the jacket — the cable looks perfect, but the inner conductor is under permanent rotational stress. With temperature fluctuations or mechanical load (wind, vibrations), that tension slowly works itself loose, causing the impedance to shift locally and the connector to make micro-movements. The result is the same as with a bad connector: rising VSWR, PIM and eventually loss of contact — but the causal link is much harder to trace.

What it really costs when things go wrong

A badly pulled coaxial cable rarely costs you just the material. The bill adds up through:

Re-entry into the mast or onto the roof, with renewed climbing work and safety inspection.
Downtime of the system connected to that feeder.
Consequential damage to radios, amplifiers or antennas due to poor VSWR.
Loss of warranty on equipment connected to an out-of-spec installation.
Audits and certificates that need to be redone.

The cheapest quote on your desk is almost never the cheapest installation in your network.

Why Mercuron does not outsource this job

A contractor who pulls coax cheaply today is unreachable tomorrow when the fault surfaces. We have seen it too often to live with it any longer. That is why Mercuron carries out professional coax installation entirely in-house:

Our own technicians with certified training on connector types (N, 7/16 DIN, 4.3-10) and the common feeder cables from CommScope, RFS and Eupen.

Calibrated tools for stripping, flaring and torque tightening. No "I reckon it's fine" work.

Sweep and DTF measurement after every installation. Every cable we deliver comes with a measurement report.
One responsible party, from cable reel to connector to weatherproofing. No finger-pointing between subcontractors.

Warranty on the entire run, not just on the material.