TV antenna adaptor

[T.T.]

My new VHF antenna has an adaptor with two short insulated wires at one end
and a screw-on attachment for the co-ax at the other end. The two wires are
meant to be connected to the arms of the antenna, using the wingnuts on the
antenna, and the co-ax is connected to the other end of the adaptor by a
screw-on device that grips the shielding of the co-ax with a threaded
cylinder and screws to the adaptor with a threaded hex-nut.

My question, before I caper around on the roof like a twenty-year-old, is
this: The resistance between the two wires, even without the co-ax or the
co-ax connector being connected, is zero. Unmeasurable. This cannot be
right? Can it?

 

[T.T.]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:3ucckrF100mckU1@individual.net...

"T.T."
My new VHF antenna has an adaptor with two short insulated wires at one
end and a screw-on attachment for the co-ax at the other end. The two
wires are meant to be connected to the arms of the antenna, using the
wingnuts on the antenna, and the co-ax is connected to the other end of
the adaptor by a screw-on device that grips the shielding of the co-ax
with a threaded cylinder and screws to the adaptor with a threaded
hex-nut.

My question, before I caper around on the roof like a twenty-year-old,
is this: The resistance between the two wires, even without the co-ax or
the co-ax connector being connected, is zero. Unmeasurable. This cannot
be right? Can it?


** Yes it is right.

The tiny windings of small RF baluns have negligible DC resistance .

One needs pretty fancy RF test gear to measure the actual impedance in the
VHF or UHF bands.



........ Phil

Thanks for that. I was checking to make sure that I had not shorted the

shield to the conductor, and confused myself no end..
Up onto the roof.

 

[Mark Harriss]

T.T. wrote:

Thanks for that. I was checking to make sure that I had not shorted the
shield to the conductor, and confused myself no end..
Up onto the roof.

Don't forget to get the polarisation correct.

 

[Phil Allison]

"Mark Harriss"

T.T. wrote:

Thanks for that. I was checking to make sure that I had not shorted the
shield to the conductor, and confused myself no end..
Up onto the roof.
Don't forget to get the polarisation correct.

** Yeah - or else you will have to wear polarising glasses when you
watch the telly.




............. Phil

 

[Mark Harriss]

Phil Allison wrote:

"Mark Harriss"

T.T. wrote:

Thanks for that. I was checking to make sure that I had not shorted the
shield to the conductor, and confused myself no end..
Up onto the roof.

Don't forget to get the polarisation correct.




** Yeah - or else you will have to wear polarising glasses when you
watch the telly.




............ Phil

Yeah you can get 3D with two antennas at different
polarisations and those coloured glasses.

 

[Jasen Betts]

On 2005-11-20, T.T. <tonyt92@yahoo.com> wrote:

My new VHF antenna has an adaptor with two short insulated wires at one end
and a screw-on attachment for the co-ax at the other end. The two wires are
meant to be connected to the arms of the antenna, using the wingnuts on the
antenna, and the co-ax is connected to the other end of the adaptor by a
screw-on device that grips the shielding of the co-ax with a threaded
cylinder and screws to the adaptor with a threaded hex-nut.

sounds like an "F" conneector.

My question, before I caper around on the roof like a twenty-year-old, is
this: The resistance between the two wires, even without the co-ax or the
co-ax connector being connected, is zero. Unmeasurable. This cannot be
right? Can it?

It's right. the transformer inside the unit is designed for VHF and has very
little wire in it. as a result it has negligable DC resistance.

Bye.
Jasen