Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [coax]

Coaxial cable, or coax, is a type of cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield.

Coaxial cable, or coax, is a type of cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield.

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Why were coax cables used for networking?

Often, if older standards become obsolete, it's because they are superseded by newer technologies. In the past networking was done using coax, instead of the twisted pair used today. Why did they use the more expensive coax? It doesn't look like the…
The Resistance
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Can I solder a RG316 coax directly to a PCB instead of using the intended SMA connectors?

I have a length of RG-316 single shield 50Ω coaxial cable carrying a 5.8 GHz signal that I need to connect to a PCB. While cheap relative to most coaxial connectors, SMA connectors are still quite expensive, take up space and are relatively heavy.…
jms
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Why are RF components and cables still so large?

With the advent of ICs in past decades, circuits have decreased in size exponentially over time. However, it appears RF components and connections, with coax SMA cable, connectors, and components, like the one below, are still hefty and large: Why…
Tosh
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Are TV coaxial cables compatible with WiFi antennas?

If I replace an old, roof-mounted TV antenna with a 2.4GHz WiFi (IEEE 802.11) antenna; can I use the existing coax? Or will I need to run all new cable?
voices
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Why do cables specify 75 Ω impedance when impedance is a two-dimensional quantity?

As I understand it, impedance has an imaginary and a real part. To be able to perform any useful calculations, one needs to know both. Cables and speakers usually only say like "8 Ω" or "75 Ω". Is that purely resistive? If so, what is so special…
Stephen Hubschrauber
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Is it possible to reject noise traveling on the outside of a coaxial transmission line?

Say I have some ordinary coax between a receiver and an antenna. That coax will have three currents in it: the desired signal an exactly equal an opposite current on the inside of the shield (really, also the desired signal) noise on the outside…
Phil Frost
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Can I use a coaxial cable as a DC power cable (without using it as a signal cable)?

On my balcony I have a satellite dish and two coaxial cables attached to it. I don't use that dish, and I want to remove it and reuse those coaxial cables to power some other device on the balcony (a kind of IoT stuff). Can I send DC power over that…
Marian Paździoch
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5V DC over Coax

I need a sanity check. My house is wired with a Coax cable that is currently completely useless to me. I want to use the coax wiring to send 5V DC power for small appliances (like Raspberry Pi's) throughout the house. I want to use this PSU:…
Milan Vrekic
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Is there ever a good reason to ground a coax cable on one side only?

In a recent amateur radio build, I deduced (most likely incorrectly) that a longish (maybe 20 cm) length of power cable carrying DC voltage to an IF board could benefit from some shielding. Careful not to introduce ground loops, I decided that…
Buck8pe
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Effects of impedance matching between 50 and 75 Ohm coaxial cables for 10 Mbit/s, Manchester-coded signals (20 MHz)

TL,DR: This is quite a bunch of text because I have included plenty of background info. However, there will finally be a good, and precise question: Should I use an impedance matching network when connecting cables of different impedance such as…
zebonaut
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Are the currents that travel on the outside of coax really "common mode"?

Consider a ladder-line transmission line. Given any currents on the two conductors, we can describe those currents as the current on each conductor individually, or: currents that flow one way on one conductor, matched by exactly equal and opposite…
Phil Frost
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Are there types of standard coaxial cable with a propagation velocity of 0.9c? What would be the application?

Reading this answer I was surprised to hear that there are "excellent" kinds of coaxial cable with a propagation speed of 0.9c; 90% the speed of light. The bargain basement number is about 2/3c, and coaxial cable with a faster propagation velocity…
uhoh
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Industry standard measure for coaxial cable stiffness?

Is there an industry standard measure for coaxial cable stiffness? By stiffness I mean the spring force experienced when bending or deforming the cable. In my search for a highly flexible lab test cable, I've been unable to find a standard…
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Coax Impedance Explanation

I have been trying for a while to understand Coaxial Cable impedances for ham radio etc. use. I only know what it is not though. Coaxial Cable does not measure the rated impedance from one end to the other Coaxial Cable does not act like a load…
skyler
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What causes common mode currents in a coaxial cable?

I have been messing around with a signal generator, an RF current probe and an open ended coax cable. From about 50 MHz onwards, I can measure a significant common mode current if I attach some wires (even short ones, about 2 cm in length) to the…
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