If you have had occasion to open up a transceiver for repair or other reasons, you have seen the thin grey coax that's used to carry signals from one part of the radio to another.

What is the designation of this coax?

  • $\begingroup$ Maybe a picture? Plenty of radios have no coax at all, or perhaps even no wires, with all connections made on a PCB. Even in radios that do have internal coax, I doubt there's only one kind. $\endgroup$ Jun 22, 2016 at 3:12

2 Answers 2


There are probably a variety of such miniature coaxial cables used in various radio equipment. My Elecraft K3 uses a TMP coaxial cable which is about 1/8th inch in diameter. It is manufactured by a Japanese company but I forgot their name. I don't think there is one single designation for such cables.


This can't be generally answered. There's quite a lot of characteristics to coax cable that are relevant to its application, and hence, device designers have the choice from a great deal of different cable and connector types.

Just to give you an idea of what one would care about, and for which there's pretty much always different choices:

  • cable RF impedance ($50\,\Omega$, $75\,\Omega$, …)
  • attenuation of desired frequency per length
  • propagation speed in the dielectric (there's different dielectrics out there!)
  • mechanical aspects such as
    • bendability
    • rigidity
    • tolerance to vibration
    • weight
    • length
  • connectors (there's literally hundreds of different PCB-Coax connection options)
    • Cost
    • attenuation
    • all the mechanical aspects above
    • well-matchedness
    • reliability of electrical data
    • expected number of plugging cycles
  • thermal stability
  • tolerance to humidity
  • maximum transportable power / field strength
  • tolerance of all the above things across
    • different points of the same piece of cable
    • different cables from the same production run
    • future production runs
  • long-term availability
  • costs

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