Wiring on old air antenna.

[JoJo66]

I have an old air antenna on my roof...probably 50 years old. I was wanting to connect it to my TV, but there is no coax cable attached to it, only a very thin wire about an eighth of an inch in diameter. I pulled some of the sheathing off and there are 4 wires: Red, Yellow, Green, Black. I'm sure this wire was run into the house at some time years ago, because it is hanging right next to the hole where cable enters my house. I have no idea how those 4 wires were used to connect to a TV years ago.
Is there any way to use this wire to connect to a balun or some other device so I can connect a coax cable?

 

[kanewolf]

Those wires sound like they were for a rotor mount (motorized rotation). The probably connected to a control box with a knob that allowed the antenna to be turned from inside the house. You will probably have to bring the antenna down and connect new coax to it. Then re install the antenna.

 

[King_V]

Old style antennas used wiring/connections that are referred to as 300 ohm twin-lead. Essentially a flat sort of cable with the two wires in it, within the edges.

http://farm4.staticflickr.com/3265/2672657175_10e7849d08.jpg

They either end in the U-shaped connectors that you see in the pic I've linked to, or, quite often, are cut with some of the insulation stripped and the bare copper wire exposed.

The ends, regardless of whether having the U-connectors or just the bare wire, would be wrapped around two screws on the back of the TV that were marked for the antenna, specifically UHF - and possibly VHF.

However, if your TV is newer than those ancient boxes, it'll likely have a coax connector instead. In that case, you'll need something like this 300 ohm to 75 ohm adapter:

https://showmecables-static.scdn3.secure.raxcdn.com/media/catalog/product/cache/image/e9c3970ab036de70892d86c6d221abfe/s/e/separator-combiner-1.jpg

The house I first bought around 1999-2000 (from my parents, who bought it new in 1978) had a huge antenna in the attic, and all the 300-ohm twin-lead wiring still throughout the house. I cancelled my cable TV service (my brother and I didn't watch much TV, and couldn't justify the cost), and simply used the antenna. There was a splitter to run the signal to various rooms in the house.

We got a very clear picture out of it back then. However, I don't know if the old analog signals are still broadcast anymore or not.

I'd thought they were doing away with them, and only broadcasting the digital signals now, even for the basic channels (ABC, CBS, etc), but don't quote me on that.


The wikipedia page on twin-lead (I didn't know it was officially called that before today), which goes into more detail.

https://en.wikipedia.org/wiki/Twin-lead

Given its weaknesses with exposure to metal, weather, etc., I suppose that's why my parents put the antenna inside the attic instead of outside on top of the roof.

 

[americanaudiophile]

If the antenna is that old it might be optimized for the lower channels not the upper ones that have most of the digital channels. That would greatly limit the number of channels you would be able to get.
If you are going up on the roof and have to wire the old one it makes more sense to buy an new antenna optimized for HD, point it to get he most channels, and use RG6 75 ohm coax to wire it.

 

[kanewolf]

@americanaudiophile has a good point. The HD channels are on high VHF and UHF if your antenna doesn't have a section that looks similar to this

You won't get good HD signal anyway.