echo47 said:An ordinary audio/music speaker? A conventional audio power amp on the other end? You can connect the coax directly to the speaker and amp. Cable impedance matching is not required or desirable in this situation.
Why not use ordinary speaker wire? It's cheaper and has lower resistance and lower capacitance than most coax.
By the way, a speaker may say "8 ohm", but it usually has a wildly complex impedance. For example, here is an impedance plot of a "4 ohm" hi-fi speaker:
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xxargs said:echo47 said:An And RG58 (one kind of 50 Ohm cable) itself have around 6390 Ohm and -45 degree characteric complex impedance on 20 Hz, 1013 Ohm and -44.92 degree on 800 Hz etc.
).
You lost me on that one. Coaxial cable characteristic impedance is ~not frequency dependent. A 50 ohm cable at 100 MHz is, surprise, still 50 ohm cable at 1 KHz. Impedance has to do with √(L/C), where L is inductance per length, and C is capacitance per length. Does not change with frequency.
biff44 said:[Edit missing removed quote]
You lost me on that one. Coaxial cable characteristic impedance is ~not frequency dependent. A 50 ohm cable at 100 MHz is, surprise, still 50 ohm cable at 1 KHz. Impedance has to do with √(L/C), where L is inductance per length, and C is capacitance per length. Does not change with frequency.