How does a TV splitter work?

[Bill Gill]

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?

Bill

 

On Oct 30, 6:45 am, Bill Gill <billne...@cox.net> wrote:

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?

Bill

If the antennas are facing the same direction and are the same model
you have created a 'stack' and will achieve +3dB and more directivity.
If the antennas are in different directions you'll get 'random' phase
cancellations. They are not actually random but can get so complex it
appears to be. If you're trying to combine different directions you
might look into 'jointennas' which are frequency selective diplexers.
They're pricey but may help reduce the interference giving you one
feed with all channels active and no rotator.

http://www.warrenelectronics.com/antennas/Jointennas.htm

Also available from Amazon

G˛

 

[Rich Grise]

stratus46@yahoo.com wrote:
....

If the antennas are in different directions you'll get 'random' phase
cancellations. They are not actually random but can get so complex it
appears to be.

I think you might mean, "chaotic."

Cheers!
Rich

 

[Rich Grise]

Bill Gill wrote:

No I don't mean the theory of how it works, I mean
how does it work in practice. The thing that brings

To use it in practice, you need to know what you're working with.

http://www.google.com/search?q=how+does+an+antenna+splitter+work%3F

Hope This Helps!
Rich

 

[Bill Gill]

On 10/30/2011 12:03 PM, stratus46@yahoo.com wrote:

On Oct 30, 6:45 am, Bill Gill<billne...@cox.net> wrote:
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?

Bill

If the antennas are facing the same direction and are the same model
you have created a 'stack' and will achieve +3dB and more directivity.
If the antennas are in different directions you'll get 'random' phase
cancellations. They are not actually random but can get so complex it
appears to be. If you're trying to combine different directions you
might look into 'jointennas' which are frequency selective diplexers.
They're pricey but may help reduce the interference giving you one
feed with all channels active and no rotator.

http://www.warrenelectronics.com/antennas/Jointennas.htm

Also available from Amazon

G˛
That really isn't a problem. The 2 antennas are at right

angles to each other, and the yagi is fairly high gain. So
it doesn't receive the signals from the side at all well.
That is why I put in the second UHF antenna (a coat hanger
antenna made to the plans readily available on the web).
The result is that I get the same good reception on the
major channels (ABC, CBS, NBC, and Fox) that I was getting
on the main antenna, which is pointed at all those transmitters
plus much better reception on all the UHF channels which are
scattered all around the area.

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

Bill

 

[Baron]

Bill Gill Inscribed thus:

On 10/30/2011 12:03 PM, stratus46@yahoo.com wrote:
On Oct 30, 6:45 am, Bill Gill<billne...@cox.net> wrote:
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?

Bill

If the antennas are facing the same direction and are the same model
you have created a 'stack' and will achieve +3dB and more
directivity. If the antennas are in different directions you'll get
'random' phase cancellations. They are not actually random but can
get so complex it appears to be. If you're trying to combine
different directions you might look into 'jointennas' which are
frequency selective diplexers. They're pricey but may help reduce the
interference giving you one feed with all channels active and no
rotator.

http://www.warrenelectronics.com/antennas/Jointennas.htm

Also available from Amazon

G²
That really isn't a problem. The 2 antennas are at right
angles to each other, and the yagi is fairly high gain. So
it doesn't receive the signals from the side at all well.
That is why I put in the second UHF antenna (a coat hanger
antenna made to the plans readily available on the web).
The result is that I get the same good reception on the
major channels (ABC, CBS, NBC, and Fox) that I was getting
on the main antenna, which is pointed at all those transmitters
plus much better reception on all the UHF channels which are
scattered all around the area.

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

Bill

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.

Resistive splitter/combiners are generally not frequency sensitive
whilst tuned ones are. A simple tuned splitter/combiner could be made
out of three lengths of co-ax cable or 300 ohm ribbon.

Whilst mechanically simple, calculating the parameters for the lengths
of co-ax or ribbon needed for a tuned splitter/combiner, is not !

Doesn't Wikipedia cover this ? I'll have to take a look...

--
Best Regards:
Baron.

 

[Baron]

Baron Inscribed thus:

Bill Gill Inscribed thus:

On 10/30/2011 12:03 PM, stratus46@yahoo.com wrote:
On Oct 30, 6:45 am, Bill Gill<billne...@cox.net> wrote:
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?

Bill

If the antennas are facing the same direction and are the same model
you have created a 'stack' and will achieve +3dB and more
directivity. If the antennas are in different directions you'll get
'random' phase cancellations. They are not actually random but can
get so complex it appears to be. If you're trying to combine
different directions you might look into 'jointennas' which are
frequency selective diplexers. They're pricey but may help reduce
the interference giving you one feed with all channels active and no
rotator.

http://www.warrenelectronics.com/antennas/Jointennas.htm

Also available from Amazon

G²
That really isn't a problem. The 2 antennas are at right
angles to each other, and the yagi is fairly high gain. So
it doesn't receive the signals from the side at all well.
That is why I put in the second UHF antenna (a coat hanger
antenna made to the plans readily available on the web).
The result is that I get the same good reception on the
major channels (ABC, CBS, NBC, and Fox) that I was getting
on the main antenna, which is pointed at all those transmitters
plus much better reception on all the UHF channels which are
scattered all around the area.

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

Bill

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.

Resistive splitter/combiners are generally not frequency sensitive
whilst tuned ones are. A simple tuned splitter/combiner could be made
out of three lengths of co-ax cable or 300 ohm ribbon.

Whilst mechanically simple, calculating the parameters for the lengths
of co-ax or ribbon needed for a tuned splitter/combiner, is not !

Doesn't Wikipedia cover this ? I'll have to take a look...

Seems its called a "Diplexer" on Wikipedia.

--
Best Regards:
Baron.

 

[Phil Allison]

"Baron"

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


Basically there are two types of splitter/combiner, resistive and tuned.

** Absolute nonsense.

Passive spitters all use tiny transformers that are wide band.



..... Phil

 

[Sjouke Burry]

"Phil Allison" <phil_a@tpg.com.au> wrote in news:9h60r0F6n9U1
@mid.individual.net:

"Baron"


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


Basically there are two types of splitter/combiner, resistive and
tuned.


** Absolute nonsense.

Passive spitters all use tiny transformers that are wide band.



.... Phil



** Absolute nonsense.

I have looked inside al of them I came across,
and found two types, the first(cheapest ones) had
the centres brutally soldered together, ignoring
mismatch.
Second type: from the feedline two 75 ohms resistors
to the two outputs, thus keeping impedance at the correct
level, accepting a bit of attenuation.
The type you mention, would be the best solution, but I have
yet to come across one of them, they are expensive, and
for wideband use, lke ~60 tv channels, unusable.

 

[Bill Gill]

On 10/30/2011 8:45 AM, Bill Gill wrote:

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?

Bill

Well, I guess that is just one of those questions that
nobody has thought about, or at least hasn't investigated.
I tried Rich's list at Google and didn't find anything
that answered my question. There may be an answer in
there someplace, but it is way down. 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.

By the way, a diplexer is not a splitter. It works
to combine signals at different frequencies for
transmission on a single cable.

Thanks,
Bill

 

[Phil Allison]

"Sjouke Burry"
"Phil Allison"

"Baron"


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


Basically there are two types of splitter/combiner, resistive and
tuned.


** Absolute nonsense.

Passive spitters all use tiny transformers that are wide band.


I have looked inside al of them I came across,
and found two types, the first(cheapest ones) had
the centres brutally soldered together, ignoring
mismatch.

** You must live in a real backwater.

Second type: from the feedline two 75 ohms resistors
to the two outputs, thus keeping impedance at the correct
level, accepting a bit of attenuation.

** Never seen one of them for forty years.

The type you mention, would be the best solution, but I have
yet to come across one of them,

** You must live under a rock.

they are expensive,

** ROTFL !!

They sell for a couple of dollars.

for wideband use, lke ~60 tv channels, unusable.

** ROTFLMAO !!!

Typical spec is from 50Mhz to 760Mhz.

Piss off fool.



.... Phil

 

[Phil Allison]

"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

 

[Bill Gill]

On 10/30/2011 7:10 PM, Phil Allison 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

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.

Bill

 

[Phil Allison]

"Bill Gill"
Phil Allison wrote:

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.



I'm afraid that isn't quite correct.

** Oh really ??????

Do you come here to ask others for info or just to be a smug prick yourself
??

No answer needed.

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.

** Same as what I wrote.


Well,

actually it is a little over 3 dB, because of circuit losses.

** Did you see the word "ideal " ??????

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.

** That is what I wrote.

But, my hypothesis is that in fact the 3 ports are
essentially a Y circuit.

** Nope.

That is a bonkers idea.

Piss off.


.... Phil

 

[Tim Wescott]

On Sun, 30 Oct 2011 08:45:39 -0500, Bill Gill wrote:

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 a TV splitter to be much more than a center-tapped 2:1
impedance transformer (if that). If so, then pumping power into one port
will give you a lot of leakage out another. Really cheap Chinese
splitters will just be a couple of resistors, or in extreme cases, a
black plastic block with nothing inside.

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

--
www.wescottdesign.com

 

[Michael A. Terrell]

Bill Gill wrote:

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?

Good splitter/combiners are directional couplers, to provide
isolation between the ports. Without isolation, you will feed part of
each antenna to the other and re-radiate it. It was one of the
parameters we tested from every vendor that wanted to sell us CATV
hardware. A 'Return Loss Bridge' is easy to build. It is used with a
TV Field Strength Meter' and a fixed signal source at the desired
frequency. You also need a 1% 75 Ohm terminator for the unused port for
the tests.


--
You can't have a sense of humor, if you have no sense.

 

[Phil Allison]

"Tim Wescott is a Cunt "

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

** But who the fuck are YOU ????????

Some bulshitting, pile of dung with NO idea.

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

** Got any proof sunshine ????

Bullshitters like you have no need of such irritations.

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

** The " hybrid " type is practically universal.

Shame to piss on that party in your pants you are having.

Asshole.




... Phil

 

[John Fields]

On Sun, 30 Oct 2011 20:47:34 -0500, Bill Gill <billnews2@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

--
JF

 

[Bill Gill]

On 10/31/2011 6:49 AM, John Fields wrote:

On Sun, 30 Oct 2011 20:47:34 -0500, Bill Gill<billnews2@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.

Thanks,
Bill

 

[John Fields]

On Mon, 31 Oct 2011 08:30:56 -0500, Bill Gill <billnews2@cox.net>
wrote:

On 10/31/2011 6:49 AM, John Fields wrote:
On Sun, 30 Oct 2011 20:47:34 -0500, Bill Gill<billnews2@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.

---
Then go to:

http://www.linear.com/designtools/software/

Download and install LTspice IV, build a splitter, and test it to find
out if what you've been saying is true.


--
JF