How does a TV splitter work?

No I don't mean the theory of how it works, I mean
how does it work in practice. The thing that brings
this up is that I just hooked 2 TV antennas in
parallel using a standard TV splitter. The way
a splitter works of course is that you hook a
signal source up to the input connector and it comes
out the 2 (or more) outputs a little over 3 dB
(or more) down. In this case of course I hook the
sources (the 2 antennas) to the output connectors
and get the 2 signals out together on the input
connector. The question that came to mind is;
Does this work the same way? Do the output signals
come out a little over 3 dB down? My first thought
is that they do. In fact thinking about it I suspect
that a signal applied to any port will come out the
other 2 ports a little over 3 dB down. But I don't
know that and don't have the equipment to test it.
So, does any body know?

I wouldn't trust ............

Really cheap Chinese
splitters will just be a couple of resistors,

"Real" radio splitters start at "hybrid splitters" (or hybrid combiners)
and get more fancy from there.

I'm afraid that isn't quite correct. When a signal is split half
the power available at the input is directed to each output. That
is what makes the typical 3 dB drop from input to output. Well,
actually it is a little over 3 dB, because of circuit losses. Now,
if you reverse the signal flow direction you will transmit the
2 input signals (into the output connectors) to the output (input)
connector. The max that you could get from either input would
be the same level that was at the input minus circuit losses.
If you put the same signal, same frequency and in phase, into
both inputs you would get the sum of the 2 input signals at the
output. But, my hypothesis is that in fact the 3 ports are
essentially a Y circuit. In that case any input into any port
would appear 3 dB down at the other 2 ports. It would be easy
enough to check if I had a signal generator and a power detector,
but I don't so that is why I asked here.

On Sun, 30 Oct 2011 20:47:34 -0500, Bill Gill<billnews2_at_cox.net
wrote:


I'm afraid that isn't quite correct. When a signal is split half
the power available at the input is directed to each output. That
is what makes the typical 3 dB drop from input to output. Well,
actually it is a little over 3 dB, because of circuit losses. Now,
if you reverse the signal flow direction you will transmit the
2 input signals (into the output connectors) to the output (input)
connector. The max that you could get from either input would
be the same level that was at the input minus circuit losses.
If you put the same signal, same frequency and in phase, into
both inputs you would get the sum of the 2 input signals at the
output. But, my hypothesis is that in fact the 3 ports are
essentially a Y circuit. In that case any input into any port
would appear 3 dB down at the other 2 ports. It would be easy
enough to check if I had a signal generator and a power detector,
but I don't so that is why I asked here.

Google is your friend:

http://michaelgellis.tripod.com/magict.html

Well, looking at the last diagram I would assume that my

On 10/31/2011 6:49 AM, John Fields wrote:
On Sun, 30 Oct 2011 20:47:34 -0500, Bill Gill<billnews2_at_cox.net
wrote:


I'm afraid that isn't quite correct. When a signal is split half
the power available at the input is directed to each output. That
is what makes the typical 3 dB drop from input to output. Well,
actually it is a little over 3 dB, because of circuit losses. Now,
if you reverse the signal flow direction you will transmit the
2 input signals (into the output connectors) to the output (input)
connector. The max that you could get from either input would
be the same level that was at the input minus circuit losses.
If you put the same signal, same frequency and in phase, into
both inputs you would get the sum of the 2 input signals at the
output. But, my hypothesis is that in fact the 3 ports are
essentially a Y circuit. In that case any input into any port
would appear 3 dB down at the other 2 ports. It would be easy
enough to check if I had a signal generator and a power detector,
but I don't so that is why I asked here.

Google is your friend:

http://michaelgellis.tripod.com/magict.html

Well, looking at the last diagram I would assume that my
hypothesis is correct, but at the same time it doesn't
really discuss what I have been saying.

"Bill Gill"

Well, I guess that is just one of those questions that
nobody has thought about, or at least hasn't investigated.

** Like hell.

I had just hoped
somebody here would know the relationship between the
3 ports.  I still think that a signal that enters any
of the 3 ports will be split between the other 2 ports
3 dB down.

** Like any transformer, there is a ratio between the inputs and outputs.

An ideal two way splitter creates two signals from one, each 3 dB down.

Used in reverse, you need two inputs that are identical to get the 3dB boost
that is possible.

30 years back, I used a 4 way TV splitter to combine 3 antennas operating on
VHF that were not co-phased.

This was followed by a two way splitter to get two signals.

It worked like a charm for a pair of 202MHz radio mic receivers.

...  Phil

On Oct 30, 8:10 pm, "Phil Allison"<phi...@tpg.com.au> wrote:
"Bill Gill"

Well, I guess that is just one of those questions that
nobody has thought about, or at least hasn't investigated.

** Like hell.

I had just hoped
somebody here would know the relationship between the
3 ports. I still think that a signal that enters any
of the 3 ports will be split between the other 2 ports
3 dB down.

** Like any transformer, there is a ratio between the inputs and outputs.

An ideal two way splitter creates two signals from one, each 3 dB down.

Used in reverse, you need two inputs that are identical to get the 3dB boost
that is possible.

30 years back, I used a 4 way TV splitter to combine 3 antennas operating on
VHF that were not co-phased.

This was followed by a two way splitter to get two signals.

It worked like a charm for a pair of 202MHz radio mic receivers.

... Phil

Hi Phil, I've got this cute little splitter from mini-circuits.
ZSC-2-2. I wanted to know how the thing worked. I opened it up and
tried to trace the wires. (Two transformers on toroid) with a resistor
and two caps?) But I couldn’t figure it out. Any idea how one of
these is wired together.

Here's a rather poor picture.
http://imageshack.us/photo/my-images/14/dscf0047uh.jpg/

George H.
John Fields found this link:

On 10/31/2011 9:13 AM, George Herold wrote:
On Oct 30, 8:10 pm, "Phil Allison"<phi...@tpg.com.au> wrote:
"Bill Gill"

Well, I guess that is just one of those questions that
nobody has thought about, or at least hasn't investigated.

** Like hell.

I had just hoped
somebody here would know the relationship between the
3 ports. I still think that a signal that enters any
of the 3 ports will be split between the other 2 ports
3 dB down.

** Like any transformer, there is a ratio between the inputs and outputs.

An ideal two way splitter creates two signals from one, each 3 dB down.

Used in reverse, you need two inputs that are identical to get the 3dB boost
that is possible.

30 years back, I used a 4 way TV splitter to combine 3 antennas operating on
VHF that were not co-phased.

This was followed by a two way splitter to get two signals.

It worked like a charm for a pair of 202MHz radio mic receivers.

... Phil

Hi Phil, I've got this cute little splitter from mini-circuits.
ZSC-2-2. I wanted to know how the thing worked. I opened it up and
tried to trace the wires. (Two transformers on toroid) with a resistor
and two caps?) But I couldn’t figure it out. Any idea how one of
these is wired together.

Here's a rather poor picture.
http://imageshack.us/photo/my-images/14/dscf0047uh.jpg/

George H.
John Fields found this link:
http://michaelgellis.tripod.com/magict.html

I think it will show the answer to your question.

On Mon, 31 Oct 2011 11:45:26 -0500, Bill Gill<billnews2_at_cox.net
wrote:

On 10/31/2011 9:13 AM, George Herold wrote:
On Oct 30, 8:10 pm, "Phil Allison"<phi...@tpg.com.au> wrote:
"Bill Gill"

Well, I guess that is just one of those questions that
nobody has thought about, or at least hasn't investigated.

** Like hell.

I had just hoped
somebody here would know the relationship between the
3 ports. I still think that a signal that enters any
of the 3 ports will be split between the other 2 ports
3 dB down.

** Like any transformer, there is a ratio between the inputs and outputs.

An ideal two way splitter creates two signals from one, each 3 dB down.

Used in reverse, you need two inputs that are identical to get the 3dB boost
that is possible.

30 years back, I used a 4 way TV splitter to combine 3 antennas operating on
VHF that were not co-phased.

This was followed by a two way splitter to get two signals.

It worked like a charm for a pair of 202MHz radio mic receivers.

... Phil

Hi Phil, I've got this cute little splitter from mini-circuits.
ZSC-2-2. I wanted to know how the thing worked. I opened it up and
tried to trace the wires. (Two transformers on toroid) with a resistor
and two caps?) But I couldn’t figure it out. Any idea how one of
these is wired together.

Here's a rather poor picture.
http://imageshack.us/photo/my-images/14/dscf0047uh.jpg/

George H.
John Fields found this link:
http://michaelgellis.tripod.com/magict.html

I think it will show the answer to your question.

---
Better yet:

http://www.minicircuits.com/app/AN10-006.pdf


Thanks John, that one does indeed seem to answer my question.

Basically there are two types of splitter/combiner, resistive and tuned.
In either case the idea is to combine two or more signals into one feed
line whilst maintaining impedance matching, hence the nominal 3 Db
loss.

On 10/31/2011 9:13 AM, George Herold wrote:



On Oct 30, 8:10 pm, "Phil Allison"<phi...@tpg.com.au>  wrote:
"Bill Gill"

Well, I guess that is just one of those questions that
nobody has thought about, or at least hasn't investigated.

** Like hell.

I had just hoped
somebody here would know the relationship between the
3 ports.  I still think that a signal that enters any
of the 3 ports will be split between the other 2 ports
3 dB down.

** Like any transformer, there is a ratio between the inputs and outputs.

An ideal two way splitter creates two signals from one, each 3 dB down..

Used in reverse, you need two inputs that are identical to get the 3dB boost
that is possible.

30 years back, I used a 4 way TV splitter to combine 3 antennas operating on
VHF that were not co-phased.

This was followed by a two way splitter to get two signals.

It worked like a charm for a pair of 202MHz radio mic receivers.

...  Phil

Hi Phil,  I've got this cute little splitter from mini-circuits.
ZSC-2-2.  I wanted to know how the thing worked.  I opened it up and
tried to trace the wires. (Two transformers on toroid) with a resistor
and two caps?)   But I couldn’t figure it out.   Any idea how one of
these is wired together.

Here's a rather poor picture.
http://imageshack.us/photo/my-images/14/dscf0047uh.jpg/

George H.

John Fields found this link:http://michaelgellis.tripod.com/magict.html

I think it will show the answer to your question.

Bill- Hide quoted text -

- Show quoted text -

On Mon, 31 Oct 2011 11:45:26 -0500, Bill Gill <billne...@cox.net
wrote:





On 10/31/2011 9:13 AM, George Herold wrote:
On Oct 30, 8:10 pm, "Phil Allison"<phi...@tpg.com.au>  wrote:
"Bill Gill"

Well, I guess that is just one of those questions that
nobody has thought about, or at least hasn't investigated.

** Like hell.

I had just hoped
somebody here would know the relationship between the
3 ports.  I still think that a signal that enters any
of the 3 ports will be split between the other 2 ports
3 dB down.

** Like any transformer, there is a ratio between the inputs and outputs.

An ideal two way splitter creates two signals from one, each 3 dB down.

Used in reverse, you need two inputs that are identical to get the 3dB boost
that is possible.

30 years back, I used a 4 way TV splitter to combine 3 antennas operating on
VHF that were not co-phased.

This was followed by a two way splitter to get two signals.

It worked like a charm for a pair of 202MHz radio mic receivers.

...  Phil

Hi Phil,  I've got this cute little splitter from mini-circuits.
ZSC-2-2.  I wanted to know how the thing worked.  I opened it up and
tried to trace the wires. (Two transformers on toroid) with a resistor
and two caps?)   But I couldn t figure it out.   Any idea how one of
these is wired together.

Here's a rather poor picture.
http://imageshack.us/photo/my-images/14/dscf0047uh.jpg/

George H.
John Fields found this link:
http://michaelgellis.tripod.com/magict.html

I think it will show the answer to your question.

---
Better yet:

http://www.minicircuits.com/app/AN10-006.pdf

--
JF- Hide quoted text -

- Show quoted text -

On Oct 31, 12:45 pm, Bill Gill<billne...@cox.net> wrote:
On 10/31/2011 9:13 AM, George Herold wrote:



On Oct 30, 8:10 pm, "Phil Allison"<phi...@tpg.com.au> wrote:
"Bill Gill"

Well, I guess that is just one of those questions that
nobody has thought about, or at least hasn't investigated.

** Like hell.

I had just hoped
somebody here would know the relationship between the
3 ports. I still think that a signal that enters any
of the 3 ports will be split between the other 2 ports
3 dB down.

** Like any transformer, there is a ratio between the inputs and outputs.

An ideal two way splitter creates two signals from one, each 3 dB down.

Used in reverse, you need two inputs that are identical to get the 3dB boost
that is possible.

30 years back, I used a 4 way TV splitter to combine 3 antennas operating on
VHF that were not co-phased.

This was followed by a two way splitter to get two signals.

It worked like a charm for a pair of 202MHz radio mic receivers.

... Phil

Hi Phil, I've got this cute little splitter from mini-circuits.
ZSC-2-2. I wanted to know how the thing worked. I opened it up and
tried to trace the wires. (Two transformers on toroid) with a resistor
and two caps?) But I couldn’t figure it out. Any idea how one of
these is wired together.

Here's a rather poor picture.
http://imageshack.us/photo/my-images/14/dscf0047uh.jpg/

George H.

John Fields found this link:http://michaelgellis.tripod.com/magict.html

I think it will show the answer to your question.

Bill- Hide quoted text -

- Show quoted text -

Thanks Bill, When I saw the magic T, I thought it was about one of
these gizmo's
http://en.wikipedia.org/wiki/Magic_tee

George H.
Well, I have worked with RF circuits at one time, and may even have

On Sun, 30 Oct 2011 19:19:42 +0000, Baron wrote:

Basically there are two types of splitter/combiner, resistive and
tuned. In either case the idea is to combine two or more signals into
one feed line whilst maintaining impedance matching, hence the
nominal 3 Db loss.

A resistive splitter will have a theoretical minimum 6dB loss. 3dB
from the split, and 3dB from resistive losses.

On Oct 31, 4:38 am, Jasen Betts <ja...@xnet.co.nz> wrote:
On 2011-10-30, Bill Gill <billne...@cox.net> wrote:

My main thing was that I am curious just how the splitter works.

    last one i looked inside had this:

                           .---------  out1
                           |__
                              3::
                              3::
                 .------------3::
     in          |            3::
       ----------|--__      __3::
                 |    3::  |
                 +----3::  `---------  out2
             7:10     3::
                      3::
                   ___3::
                  |
                 === 10n(?) ceramic
                  |
     ----------------------------------

   I'm not sure how to analyse that.

That looks like figure 4. in the app note that JF posted. Is there a
resistor across the outputs?