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#207231 - 10/09/12 10:02 PM Odd Old Outlet
Webmaster Offline

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Registered: 10/07/00
Posts: 3142
Loc: NY, USA
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This outlet is in the family room of my house and was wondering if anyone knew what it is?

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#207232 - 10/10/12 05:58 AM Re: Odd Old Outlet [Re: Webmaster]
wire_twister Offline
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Registered: 07/25/07
Posts: 265
Loc: Georgia USA
Looks like it is for a 300 ohm television antenna.
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#207233 - 10/10/12 08:00 AM Re: Odd Old Outlet [Re: Webmaster]
jdevlin Offline
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Registered: 08/07/02
Posts: 402
Loc: welland ontario canada
Agree. 300ohm flat antenna cable for TV or FM radio.

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#207258 - 10/11/12 12:42 PM Re: Odd Old Outlet [Re: Webmaster]
geoff in UK Offline
Member

Registered: 12/30/02
Posts: 169
Loc: UK
I agree the faceplate looks like its for flat feeder but why two coax behind? In UK these would be 50ohm or most likely 75ohm. Can't work out the internal resistor/capacitor connections from the photo, but perhaps some kind of multi outlet signal distribution system???

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#207259 - 10/11/12 03:36 PM Re: Odd Old Outlet [Re: geoff in UK]
ghost307 Offline
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Registered: 05/09/05
Posts: 876
Loc: Chicago Illinois USA
It's probably working as a balun to match the 300 Ohm to coax or vice versa.


Edited by ghost307 (10/11/12 03:36 PM)
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#207291 - 10/13/12 10:29 PM Re: Odd Old Outlet [Re: Webmaster]
Beachboy Offline
Member

Registered: 09/02/06
Posts: 26
Loc: Wamego, Kansas USA
I've had the same type of outlet in several apartments I've lived in back in the 70's. This was before the days when cable TV was common, and the apartments usually had a master TV antenna, which was amplified, and the 75 ohm coaxial signal was run to an outlet such as these in each apartment. The balun adapted the 75 ohm signal to the balanced 300 ohms required by most TV's of the time. I'd say these were installed before TV's commonly had 75 ohm inputs (before 1980 or so). Cable TV and the need for separate runs to each customer pretty much eliminated the need for these types of outlets. The modern day equivalent is the 75 ohm jack mounted to a wall plate.

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#212418 - 01/06/14 12:32 AM Re: Odd Old Outlet [Re: Webmaster]
JoeKP Offline
Member

Registered: 03/29/08
Posts: 144
Loc: Berkley, MA
2 wires is i think in and out, but seems like for tv/radio
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#212420 - 01/06/14 06:05 AM Re: Odd Old Outlet [Re: Webmaster]
ghost307 Offline
Member

Registered: 05/09/05
Posts: 876
Loc: Chicago Illinois USA
Beachboy's right on the money.

That's a wall plate for an older style TV set.

It has a balun as part of its construction so it can take 75 Ohm in the wall and feed 300 Ohm to the user in the room.
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#212423 - 01/06/14 10:50 AM Re: Odd Old Outlet [Re: Webmaster]
WESTUPLACE Offline
Member

Registered: 03/29/04
Posts: 252
Loc: Kingwood, TX USA
Back in the late 60's and early 70's i install hundreds of these. That outlet is made by Blonder-Tongue. Jerrold also made them. They were tap style. Each had a tap rating in db as to how much signal they passed from the trunk cable. They made them in 300 Ohm screw terminals or 75 Ohm F or G jack. You would put 8 or so on a run using lower loss taps to the end. This would compensate for the cable loss. Most were rated for VHF signals only, any UHF stations were converted to VHF at the Head End. Channels were received by an antenna, UHF converted to VHF, amplified, and distributed thru splitters and then to drops to which these outlets were installed. Mostly used in apt & multi-unit housing.

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