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How Much Signal Loss Does 10 Meters of RG58 Have? (With Loss Table)
A ham installs a 10 m RG58 run to a VHF antenna and wonders why the SWR meter looks fine but the signal is weak. Another engineer runs the same cable from a 2.4 GHz radio to a roof antenna and loses most of the power before it reaches the antenna. … More
Posted on 10/13/2026
RF Link Budget Basics: A Worked Example From Radio to Antenna
An RF link budget adds radio power and antenna gains, then subtracts cable and propagation losses to estimate power at the receiver. A useful link budget example also compares that result with receiver sensitivity for the actual modulation, bandwid… More
Posted on 10/13/2026
Can You Use 75 Ohm Cable in a 50 Ohm System? What Actually Happens
Someone has 2 m of RG6 left over from a satellite install and a 50 ohm spectrum analyzer on the bench. Will the 75 ohm cable damage anything, or ruin the measurement? The answer is usually no for a short run at low frequency, but the numbers are wo… More
Posted on 10/13/2026
Coax Bend Radius Rules: How Tight Is Too Tight?
An engineer routes an RG316 jumper around a heat sink inside a compact radio. The cable makes a hard 90 degree turn only 8 mm from the SMA connector. Day one, the VSWR is 1.35:1. After thermal cycling it creeps to 1.9:1, and the return loss notch m… More
Posted on 10/13/2026
SMA vs RP-SMA: How to Tell Them Apart (and Why It Matters)
An antenna screws onto a router, but the link barely works. The shell fits; the center contacts do not. SMA and RP-SMA use similar threaded bodies, so thread engagement alone is not proof of a valid RF connection.SMA and RP-SMA differ in the center… More
Posted on 10/13/2026
Waterproofing RF Connections: IP67 Connectors, Tapes and Boots
A rooftop 4G antenna works well all summer. After the first monsoon the signal drops 10 dB, and when someone finally opens the connector, there is a teaspoon of water in the N-type plug and a green crust on the center pin. The cable was fine. The t… More
Posted on 10/13/2026
Why Is Coaxial Cable 50 Ohms? The Physics and the History
Open any RF lab and almost every cable, connector and instrument is 50 ohm. Cable TV is 75 ohm, twisted pair Ethernet is 100 ohm, and nobody asks why. So why did RF engineering settle on 50 ohm? The popular story says it was an accident of history.… More
Posted on 10/13/2026
Phase-Matched Cable Assemblies: What They Are and When You Need Them
Two cables of the same type, both cut to 500.0 mm, are connected to the two inputs of a phase detector. The reading says 14 degrees of phase difference at 10 GHz. The cables are the same length, so the question is how. The answer is that physical … More
Posted on 10/13/2026
How to Calculate Cable Length in Wavelengths (and Why Phase Matters)
Cable length in wavelengths equals physical length divided by the wavelength inside the cable: N = Lf / (c x VF). Multiply N by 360 to obtain electrical length in degrees, using the cable velocity factor VF rather than free-space wavelength.Two 300… More
Posted on 10/13/2026
How Many Mating Cycles Can an SMA Connector Survive?
A production test fixture mates and unmates the same SMA cable 200 times a day. After three weeks, return loss at 12 GHz drifts and nobody can find a damaged part. The connector did not break. It wore out, and the datasheet number for mating cycles… More
Posted on 10/13/2026