Need to replace a 40 year old television antenna wall jack - help!
 

Hi,

I live in a 44 year old apartment building in Manhattan. I'm currently
doing renovations and I've removed an old, dented, paint-encrusted TV
antenna wall jack from the living room. I'd like to replace it with
its modern equivalent so I can use the building's roof antenna for
HDTV and FM radio reception.

I don't know exactly what this thing is or how to replace it properly.
Ideally I'd like to have a standard 75 ohm coax output. Any help would
be appreciated. Here's a description of the old jack:

The jack accepts 2 coax cable inputs at the back. and provides 2 screw
terminal outputs on the front. The screw terminals on the front are
presumably for the old standard 300 ohm TV wiring. Here's a
schematic:

COAX 1 COAX 2
| |
| |
resistor 1 no connection
|
|
resistor 2 no connection
| |
| |
screw terminal screw terminal
300 ohm 300 ohm

Please reply to dschwarz but do not spam me - my email domain is
verizon dot net.

Thanks,

Dan

My best advice is for you to print you own email and take it to you nearest
Radio Shack. They will put you on the right track.


--james--

Yeah, tried that. The local Radio Shack clerk stared blankly at the
old jack then led me to a rack of 75 ohm coax TV wall jacks. Right
output... wrong input. The local store has absolutely nothing like
this.

Dan


"James Nipper" wrote in message ...
My best advice is for you to print you own email and take it to you nearest
Radio Shack. They will put you on the right track.


--james--

040513 2051 - Dan posted:

Hi,

I live in a 44 year old apartment building in Manhattan. I'm currently
doing renovations and I've removed an old, dented, paint-encrusted TV
antenna wall jack from the living room. I'd like to replace it with
its modern equivalent so I can use the building's roof antenna for
HDTV and FM radio reception.

I don't know exactly what this thing is or how to replace it properly.
Ideally I'd like to have a standard 75 ohm coax output. Any help would
be appreciated. Here's a description of the old jack:

The jack accepts 2 coax cable inputs at the back. and provides 2 screw
terminal outputs on the front. The screw terminals on the front are
presumably for the old standard 300 ohm TV wiring. Here's a
schematic:

COAX 1 COAX 2
| |
| |
resistor 1 no connection
|
|
resistor 2 no connection
| |
| |
screw terminal screw terminal
300 ohm 300 ohm

Please reply to dschwarz but do not spam me - my email domain is
verizon dot net.

Thanks,

Dan

Here is the Winegard WebSite, with a selection of splitters and wall
outlets. If the system you described is part of a complete distribution
system for the apartment building, removing the wall outlet will eliminate
the signal to the outlets after it. It sounds like the outlet that you have
is a feed thru outlet that comes from an outlet either above or below --
probably above -- and then continues the signal on to the next outlet. You
could send an Email to the Winegard company and let them know what you want
to replace and then go from there. Instead of the screw terminals for the
300 ohm cable outlet, you could go with the 75 ohm coax output. Be sure you
ask for the feed thru type outlets.

http://www.winegard.com/offair/splittersoutlets.htm

If we presume that the poster who says it is part of a distribution system
is right, and I have no experience with that setup to either agree or
disagree, let me propose a simple solution, which if it doesn't work will
have not caused any real grief.

The screw terminal are 300 ohm twin lead, right? You want 75 ohm cable,
right?

Go back to the yo-yo at RS and tell him you want an Indoor/Outdoor 75W to
300W Matching Transformer
Catalog #: 15-1230

This will set you back 5.49 plus tax. The installation will be obvious. Open
the package carefully and if this is not the answer take it back for a
refund.

Charlie (who spent 3 years as a retiree peddling stuff for RS)

You've got questions, we've got answers (Please notice that NOBODY ever
said they were the right answers)


"Dan" wrote in message
om...
Yeah, tried that. The local Radio Shack clerk stared blankly at the
old jack then led me to a rack of 75 ohm coax TV wall jacks. Right
output... wrong input. The local store has absolutely nothing like
this.

Dan


"James Nipper" wrote in message
...
My best advice is for you to print you own email and take it to you
nearest
Radio Shack. They will put you on the right track.


--james--

Dan wrote:

The jack accepts 2 coax cable inputs at the back. and provides 2
screw terminal outputs on the front. The screw terminals on the
front are presumably for the old standard 300 ohm TV wiring.
Here's a schematic:

COAX 1 COAX 2
| |
| |
resistor 1 no connection -- ?????
|
|
resistor 2 no connection -- ?????
| |
| |
screw terminal screw terminal
300 ohm 300 ohm

Sorry, but I can't make much sense out of the drawing. The
resistors (where are the other ends??) and the "no connects"
are a big mystery from this end.

Any clue as to Coax 1 / Coax 2, which is the input feed and
which is the outgoing feed? If so...

You need is a simple "Directional Coupler". Probably a 14dB
version. A DC is an unbalanced 2-way splitter. Instead of
both splits being -3.5 dB down like a conventional 2-way,
one leg is very low loss ( typically 1dB) and the other is
high loss (-14, -16, -22dB etc.)

It has 3 female coax ports: IN / OUT / TAP. The distribution
cables (the 2 on the back of your current gizmo) go to the IN
and OUT, there is very little loss between them, the idea being
to pass along as much signal as possible to the next guy.

The TAP port is the "high loss" leg which will poke out through
your new wall plate, having a single hole in the middle for your
coax connection. You secure it to the plastic plate with a hex
nut.

--
TP / Network Man __________________________________
If u want the races for free,
somebody has to pay for it. ($1 Earl)