FAQ
What is the best coaxial cable for my application?
As always - there is no _the_ best cable, but always only a sensible compromise. How thick can the cable be, how do I run it outside? Do I want to take the cable with me on a plane trip, so is the weight important? Do I want to do DX on the 23cm band, so do I need a cable with extremely low attenuation?
What diameter should the coaxial cable have?
There are cables from less than 2mm up to several dozen centimetres in diameter. Thicker cables have lower attenuation and can transmit higher power. Choose the cable with the largest diameter that fits best in the environment of feasibility (size of hole in the wall), installability (flexibility of the cable), price and your requirements in terms of performance and attenuation.
My Wifi router (or Helium Miner) has such a very small connector, about 5 mm in diameter.
Is this connector available for every cable?
Is this connector available for every cable?
It is most likely an SMA connector. This connector is available for many cable types, including 10mm cables with low attenuation. However, you have to ask yourself whether it makes sense to run this from the antenna to the terminal. Often a compromise of a thick cable with common connectors (N-type) and the use of an adapter cable (pigtail) is more practicable at the device. The somewhat higher attenuation caused by this combination is then accepted.
I often read about "RP-SMA" connectors. What is that?
RP stands for "Reverse Polarity" and means nothing more than that the inner conductor has an inverted design (calyx or pin) than is usually expected.
This variation became common in the early 2000s with the growing popularity of WLAN antennas in order to somewhat limit the proliferation of very powerful antennas - and thus much too high levels for the shared frequency band. In the meantime, RP connectors are available for very many designs (RP-BNC, RP-TNC, RP-SMA, RP-N, etc.), they are mostly used in the Wifi area.
This variation became common in the early 2000s with the growing popularity of WLAN antennas in order to somewhat limit the proliferation of very powerful antennas - and thus much too high levels for the shared frequency band. In the meantime, RP connectors are available for very many designs (RP-BNC, RP-TNC, RP-SMA, RP-N, etc.), they are mostly used in the Wifi area.
