Can I use 50 ohm cable with 75 ohm antenna (without any adapter)?

I found on the internet that 75 ohm cable can be a problem with 50 ohm antenna, but does vice versa make the same problem? Or the combination of the 50 ohm cable with the 75 ohm antenna is more tolerant?

  • \$\begingroup\$ It can cause problems either way. \$\endgroup\$
    – Andy aka
    Oct 10 at 12:54
  • \$\begingroup\$ For reference you can read this article. \$\endgroup\$
    – Syed
    Oct 10 at 13:09
  • \$\begingroup\$ Biggest problem for the unwary is that the connector pin sizes may be different, and one way round (don't ask me which!), the larger pin can damage the smaller socket, turning a minor problem into a major repair job. \$\endgroup\$ Oct 10 at 13:12
  • 1
    \$\begingroup\$ With a strong signal environment, you'll probably get away with it. With bad luck on cable lengths, or weak signals, using the correct cable for the antenna and equipment could be the difference between it working well and not at all. \$\endgroup\$
    – Neil_UK
    Oct 10 at 15:48

If I did my math right, a 50 ohm/75 ohm mismatch equates to a loss of less than 0.2 dB. This amount of loss is inconsequential in all but the most sensitive or demanding applications.

  • \$\begingroup\$ It's not really loss that matters, it's ISI. TV can be fairly sensitive to that. \$\endgroup\$
    – hobbs
    Oct 11 at 4:06
  • \$\begingroup\$ I'll have to think about that. Does ISI really apply to a modulated base-band signal, which is what an over the air (OTA) TV signal is? \$\endgroup\$
    – SteveSh
    Oct 11 at 10:20

With both antenna and TV tuner input impedance being 75 Ω, the ideal choice of coaxial cable impedance would be 75 Ω.

However, with a strong local station, a 50 Ω cable with matching connectors would hardly make any difference to the received signal.


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