How does a TV splitter work?

[George Herold]

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.

 

[Bill Gill]

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

 

[John Fields]

On Mon, 31 Oct 2011 11:45:26 -0500, Bill Gill <billnews2@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

 

[Bill Gill]

On 10/31/2011 1:52 PM, John Fields wrote:

On Mon, 31 Oct 2011 11:45:26 -0500, Bill Gill<billnews2@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.

If the device is properly designed then sending a signal into
the 2 outputs (now inputs) will cause a signal at the input port
that equals (input1 - 3dB) + (input2 - 3dB). And there will be
no output from either of the 2 input ports. That of course
assumes ideal conditions which probably don't apply, but at
least the results will be in that ball park.

I can see that you have a lot more patience with Google than
I do. When I see a long list of things in the search results
that don't apply I give up pretty quick.

Thanks Again.

Bill

 

[Fred Abse]

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.


--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)

 

[George Herold]

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.

 

[George Herold]

On Oct 31, 2:52 pm, John Fields <jfie...@austininstruments.com> wrote:

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 -

Ahh, Thanks John, The two transformers are as shown in figure 4, One
for impedance matching and the other to do the splitting. (?)

George H.

 

[Bill Gill]

On 10/31/2011 3:07 PM, George Herold wrote:

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

come in contact with one of those things upon a time, but it has
been a while, and I have forgotten most of that sort of thing.

Bill

 

[Baron]

Fred Abse Inscribed thus:

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.

Agreed !

--
Best Regards:
Baron.

 

[Jasen Betts]

On 2011-11-04, George Herold <gherold@teachspin.com> wrote:

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?

no resistor.
it was cheap one, hard, brittle plastic shell, "PAL" connectors
made from pressed steel arranged with their axes in a Y formation
zinc plated steel skeleton, no pcb, just bits soldered together.

It woked sort of, but there was interferance between the output ports,
put the tv on one channel ad the stuff on the opther port would get
noise on a different channel adding that resistor would have no doubt
helped, but back then I'd not even heard of a hybrid. only knew how to
solder it back togethern after someone tripped over the antenna lead,
or jammed it against the wall etc.

--
⚂⚃ 100% natural















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