50Ω VS 75Ω

[stecle]

I am going to be putting up a tower at my cottage in about a month from now. I will be installing an onmidirectional WIFI antenna and a discone scanner antenna. I know that the impedance of these antennas is 50Ω. My dilema is that I have several hundred feet of RG-11 left over from a MDU install, which of course is 75Ω, that I would like to use.

The research that I have done shows that the difference between these cables would be negligible on receive. This would be ok on the discone but the WIFI antenna both transmits and receives.

I would appreciate any feedback.

Thanks

Steve

[Smith, P.]

"The research that I have done shows that the difference between these cables would be negligible on receive." - if you mean attenuation, then it will be not enough.
It will bring much more issues as reflections and you'll lost a lot of signal.

There is a method of matching impedance, but it will cost you for two of them - on each side of RG-11 chunk.

[jpmarto]

Here's one link that might help. Although at these frequencies the matching sections would be mighty short and we're talking minimum 4 extra connectors. I'm guessing the height of the antenna would trump the (close to 2:1) SWR, but the length of the coax run would trump any overall gain.

Could you possibly use a USB wireless NIC up on the tower and connect it to your home system with a usb to cat5 cable setup?


Using CATV Hardline for ham radio antennas

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[stecle]

Thanks for the great info guys! I think I will bite the bullet and buy the 50 ohm. Anyone want to buy a few hundred feet of RG-11?

[ke4est]

I would but the shipping would kill me

[Comptech]

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If you are only recieving the difference would not mean anything. On transmit it would be different.I run all my comm recievers on solid copper quad RG6. My Icom75 on a 400 foot end fed wire can here around the world on SOLID cooper quad and my BCT15 on a scantenna two can pick up UFH from over a hundred miles away. I would worry about the quality of your 75 ohm cable than the impedance. Again though, if you want to transmit it is a differnt story.