Re: [Discuss-gnuradio] What impedance are the wires and antenna?

[Jonathan Coveney]

Thanks Eric!

2009/7/28 Eric Blossom <address@hidden>

On Tue, Jul 28, 2009 at 03:37:02PM -0400, Jonathan Coveney wrote:
> Well, maybe that's the wrong way to phrase it. I need to make or buy an FM
> antenna (I realized I accidentally grabbed the VERT900 from my lab, and they
> don't have an FM antenna).
>
> Some sites seem to imply that coax is usually 70 ohm, but it looks like here
> http://wireandcable.thermaxcdt.com/item/high-performance-coaxial-cables/mil-c-17-coaxial-and-twinaxial-cables/m17-113-rg316-id-72-?&seo=110
> That the Thermax RGS-316 may be 50 ohm? I just need to know so I don't ruin
> it...
>
> I checked ettus labs and couldn't see an answer.

Antenna:

 http://www.radioshack.com/product/index.jsp?productId=2062691

75 ohm Matching transformer (close enough):

 http://www.radioshack.com/product/index.jsp?productId=2062054

Then you need an F-to-BNC and BNC-to-SMA or something similar, unless
you're plugging it into a TVRX (which has an F-connector).


Coax is commonly either 50 ohm or 75 ohm.  Cable TV uses 75 ohm.
For this application, either will work fine.

Eric