Your Computer Network, Under the Hood: What Kinds of Coaxial Cables Are There?

If you are one of those people who prefer their connection to be of the ethernet kind, then you most certainly had to extend it at some point. Because, let’s be honest, whatever default package you get is bound to become inadequate after some time, right? A lot of people choose gigabit ethernet over coax to upgrade their connection, but not a lot of people actually have any substantial knowledge about the various coax cables that exist, nor their applications.

Wiring in a house

Coaxial cables are actually a significant factor in various industries, and not all of them are good for everything! If you ever think about going all DIY on this topic, you will need to be able to tell them apart. So, we put together this little guide on the topic to give you a crash course.

RG-6 coax cables

Depending on what material their core is made from, there are CCS (copper clad steel) and BC (bare (solid) copper) RG-6 cables. They come in four distinct types: Plain, Flooded, Plenum, and Messenger, meant for different uses.

Plain, also known as “house”, is used for house wiring, whether external or indoors. However, if you have to do a direct burial or need to set up an underground conduit, then you will need the Flooded type, which has water-blocking gel infused into it.

Plenum RG-6 cables are a rather expensive option, and more geared toward experts. They feature a special outer jacket based on Teflon, which was introduced to meet the fire codes when installing coax cables in ventilation systems. The reason for this is that Plain cables (the most widespread) use plastic for their insulation, which produces poison gas when it burns.

Finally, the Messenger type was named that way because it features a “messenger wire” made of steel, which is meant to carry the tension along the cable’s length that builds in aerial drops from utility poles. For a more detailed look at RG-6 coax cables, you may want to check out this article.

Radiating coax cables

These types of cables are also known (maybe a little funnily) as “leaky cables” or “leaky feeders”. They are constructed using round tubing made of gold, copper, or silver, and they have tuned slots cut into the cable shield. The slots themselves are tuned to a specific wavelength according to the given operation that the cable will be used in, or they may be tuned to a particular radio frequency band.

These cables are used to provide leakage on purpose – a desired bi-directional effect between the receiver and transmitter. The radiating coax is most frequently used in underground transport tunnels, installed in elevator shafts, or wherever a standard antenna is not a very feasible solution.


Semi-rigid coax cables

This form of the coaxial cable uses solid copper for its outer sheath, and compared to cables which feature braided outer conductors, especially at high frequencies, its screening is far superior. One big downside to them is, just as the name hints, that they are not all that flexible, and after the initial forming, you are never supposed to bend or flex them again.

As an alternative, in those scenarios where you have to have some flexibility, the “conformable cable” has become the standard replacement for the semi-rigid. These cables can be stripped and re-formed by hand, without needing any special tools.

Rigid line coax cables

These types of lines are typically connected using one particular type of connector, known as the EIA RF, which you can learn more about at this link: Rigid line coax cables are made by two copper tubes, which rely on PTFE supports installed every other meter along their length to help keep them concentric. As their name implies, they cannot stand being bent, so when they have to make a turn, elbows are the immediate go-to solution.

Rigid lines are most commonly used in indoor applications, in order to connect high power transmitters with some other RF components, but there is another variety meant specifically for outdoors use. These outdoor rigid lines are made to be resistant to harsh weather conditions, and you can typically find them on antenna masts, for example, especially antenna splitters and broadcasting antennas.

Hard line coax cables

These types of cables use either round copper, gold, or silver, or some combination of those materials, for their shield, just like the radiating coax cable type. Aluminum shielding may be encountered on the models of lower quality; however, aluminum is very quick to oxidize, and then its effective conductivity dramatically drops. So, stay far away from those, and if you are looking to lighten the load on your budget, look into some other alternatives – never skimp on your conductors.

They are extremely widespread, being used in the broadcasting industry, and numerous other variants of radio communication services, too. When they are applied in some context where they will be exposed to the elements, these cables can feature a PVC jacket for extra protection.

These cables are well known for their significant thickness, being 13 millimeters (half an inch) at the very minimum and going up to several times that thickness. Even at rather high power, the loss they suffer is minimal, and therefore they frequently find their place in connecting a transmitter that is set up on the ground with an aerial or antenna on a tower.


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