For the Cable Guys: Coax cable Splitter Q.

[Michael Stoic]

Coaxial cable 2-way splitter: Should there be continuity between the two leads (between the center electrode and the outer sheathing with the threaded connectors)?

I have three of these splitters, two are brand new (Ideal 1GHz 2-Way Cable TV Splitter; coax connection; one in, two out) and one is used, unknown brand. Tested with a Triplett 2030-A tester. All 3 show continuity, at negligibly small resistance, between the two leads.

I've tested the splitters with the cables attached and without cables attached (only a copper pin to connect to the supposedly shielded center). In all cases continuity exists between both leads.

I also tested the coaxial cables, with the crimped ends. All test normal, i.e. - continuity throughout each lead, at both ends, but not between the leads. This isolates the splitters, but am I interpreting things correctly?

My natural instinct is that there should be continuity at both ends of each connection, but _not between_ them. But then, what do I know. So, for any cable guys, out there: do I have three bad splitters, three good spliters? What am I missing?

[Jeff Prevett]

I'm 99% sure that these splitters are either bad or you are accidentally shorting the shielding when making the tests. The outer shield is that, a shield which should be connected to ground. If there is continuity between the lead and the shield, you would be shorting out the signal to ground.

Jeff

[Greg]

You are looking at the windings of impedance matching transformers. TYou can't trust a DC meter, at 100 meghertz they look like 75 ohms, just like the cable.

[Longtime Lurker]

It's only a short at DC, which is what your meter is measuring. These devices are essentially transformers, and at RF, the inductance of the windings provides the proper impedance matching. (Assuming all the ports are properly terminated.)

In short, the OP's measurements are exactly what would be expected. At DC, there should be continuity between all four terminals of a two way splitter. (It, Out2, Out2, shield/case.) It looks something like this:

(------ Out 1 In ---) ( ) (---+-- Shield ) | ) (------ Out 2 Shield -+-) ( | | (---+-- Shield \--Case-+

(Note, it may not be clear, but the shield side of each winding is connected to the case, and as such, they are all tied together.)

To the OP: Do you have a specific problem with your equipment, or are you just measuring for fun?

[Tony Hwang]

Hi, You are looking at transformer coupled stuff. No continuity with meter. Toroidal core and windings. RF energy is split/transfered by tiny tranformer. Tony

[Tony Hwang]

Yup, that's why coax is called unbalanced line. Tony

[Michael Stoic]

I measured for the sake of double cheching the assembly before it is inside the wall.

MS